How to protect brass from oxidation

How copper corrosion occurs in water, alkali, and acid. Protection measures

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

Corrosion of copper in the soil is mainly caused by the influence of acids contained in the soil. Compared with the effects of water, oxygen in the soil oxidizes metal elements much less. The most dangerous microorganisms in the soil are, or rather, their secretions. They are often capable of releasing hydrogen sulfide, which destroys metal. Thus, copper lying in the soil for a long time can completely decompose.

In humid air the process does not proceed rapidly. It takes a long time. In a dry climate, destructive effects may not be observed at all. This is explained by the fact that in humid air there is a high concentration of carbon dioxide, sulfides, chlorides, which cause corrosion and are destructive to the protective film.

Prolonged exposure to humid air can cause the formation of a patina layer. This is the name given to green deposits on copper. It consists of salt oxides, which are initially dark brown in color, and then the surface begins to turn green.

The peculiarity of patina is that it cannot be dissolved in water and is not affected by high air humidity. It has neutral properties to copper itself, which allows it to protect the surface from the harmful effects of the environment.

In addition, modern methods of creating artificial patina make it possible to use it in objects of art and during restoration.

Look at your personal experience in combating corrosion with the help of inhibitors.

Source: https://oxmetall.ru/metalli/med/kak-protekaet-korroziya-medi

Does brass oxidize? — Metals, equipment, instructions

Anyone who searches for and sells non-ferrous metal sometimes has doubts about the type of scrap and, accordingly, its true value upon delivery.

Copper is a non-ferrous metal, and brass is an alloy that is typically 70% copper, so it often resembles it.

A mistake can be quite costly. For copper at collection points they give 285-300 rubles, for brass - about 150 . There are many ways to find out what kind of metal we see - copper or brass, and we will tell you how to distinguish them from each other in this article.

What is copper and brass

Copper is a non-ferrous metal. Its color is reddish-pink, it is pliable when working, soft and malleable. It has high thermal and electrical conductivity, so copper is often used to produce:

• parts of electrical appliances;
• cables;
• radiators.

Copper is not hardened because it becomes hard even after cold forging. It tends to become covered with patina - a green coating that occurs when the ambient humidity is high.

https://www.youtube.com/watch?v=s2-0hGlxXgw

To increase strength, improve a number of other indicators and reduce the cost of the material, impurities are added and an alloy is obtained.

One such alloy is brass .

In the classic version it contains a third of zinc.

Brass is golden yellow, stronger and harder. It does not oxidize so intensively , and is not so plastic.

Sometimes, depending on the purpose of the alloy, they add:

• tin;
• silicon;
• lead;
• manganese.

Similarities and differences

Brass alloy consists mostly of copper, so it is natural that they are similar not only visually, but also in some properties. The more copper in the alloy, the more similar their colors will be. This is where the exact coincidences end.

Visually, less than 80% copper are easily distinguished . They are slightly similar to gold, as they have a pronounced yellow tint. The more zinc, the lighter the shade.

Because of this, brass is even used to counterfeit or imitate gold . Copper has a main shade of reddish, which often has a pink tint.

With a strong decrease in temperature, brass does not lose its relatively limited ductility and does not become brittle . Conducts electricity and heat worse.

They differ in such a way as hardness .

Copper is softer and more ductile , while brass, on the contrary, is hard and it is difficult to give it any shape without annealing.

The shavings are also different: for brass they are needle- shaped , for copper they are twisted into a spiral .

Let's look at the properties that brass and copper have and whether they have any differences:

Copper	Brass
Plastic, soft	Solid
Reddish-brown-pink tint	Golden tone
Lower sound on impact	Alt
Heavy	Easier
The shavings are twisted into a spiral	Needle shavings

Most often you can distinguish by:

• mind;
• weight;
• degree of hardness

without the use of any tools or equipment.

But there are situations when, for accuracy, it is necessary to use :

• reagents,
• tools,
• devices.

Before assessing the scrap that you are going to take to the collection point, you need to clean it of dirt, otherwise you won’t be able to accurately determine it by eye.

Both metals, although to varying degrees, can develop a patina .

Therefore, do not forget to clean the scrap well.

If an object has been in the open air or in water for a long time, the patina layer is difficult to remove.

Sometimes it will be justified to purchase a special cleaning product .

It is advisable to inspect the scrap under a powerful white light.

This implies that one can view either under the sun on a fine day or under a bright fluorescent lamp . Incandescent lamp is not suitable.

Pure copper will have a reddish-brown tint, sometimes with a pink tint. Keep in mind that brass can be red or orange. This type is commonly used for decorations and water pipes.

If the material has an orange, yellow or golden tint, you can be almost sure that it is brass.

Source: https://spb-metalloobrabotka.com/okislyaetsya-li-latun/

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WATCH THE VIDEO ON THE TOPIC: Polishing brass in St. Petersburg. Protection of brass from oxidation. all-audio.pro

Varnish for brass to prevent it from darkening

Skip to content. You have JavaScript disabled. Some functions may not work. Please enable JavaScript to access all features. Posted September 13 - Anyone know how to weatherproof it? A solution of celluloid in acetone and other solvents. Used to protect printed circuit boards. Not sure it will withstand weathering. Better than any regular waterproof varnish, starting with nitro.

You just need to properly degrease the surface and apply several layers so that it does not peel off and there are no cracks in the future.

Otherwise, everything will become covered with spots and mesh. Or maybe it can be laminated into film? Posted September 14 - HTML mode enabled. The visual editor is not available while HTML is enabled. You may lose some formatting when you turn off HTML mode and return to visual.

System for IP communities. Protection of brass Author Danev, September 13 Posted September 13 — Dear colleagues, Please share your experience. The editorial team had the conceit of making the “KYA” façade sign out of polished brass. Possibly tombaka.

So in some places it gradually darkens from the splashes of water, and our women do not like this. Or to nothing? Sent on September 13 - it is gradually darkening in places due to splashes of water.

There is an ancient method that has been tested for centuries. A watchman is appointed, who every morning walks over the brass with a piece of felt boots. It works radically!

Posted September 13 - Exactly. Asidol, GOI paste and a piece of an overcoat - “our” method! Don’t you now have an anchor on the pedestal in front of the entrance? Otherwise you need to sharpen it. Also regularly. Sent on September 13 - Give free rein to you, my darlings - we'll send the entire editorial staff to the pit. Apparently, Frum will have to do it like an old mechanic. Sent on September 13 - What about acrylic auto varnish?

Posted September 13 - Old anglers use passivation. For a sign, I don’t know, it’s a bit large. The recipe is this: Clean, polish, degrease. For 1 - 2 seconds, lower 1 part nitric acid and 1 part sulfuric acid into the solution. Immediately transfer chrompic into a saturated solution of potassium dichromate.

Keep for 10 - 15 minutes. Rinse and dry. The film is resistant and not afraid of moisture. Holds even in sea water. Well, or felt boots Posted on September 13 - Tsapon-lak. All varnishes on polished brass are highly visible. The appearance of the product is greatly inferior. In addition, they are short-lived. They become cloudy from ultraviolet radiation. They crack due to temperature changes. By the way, a solution of celluloid in acetone with a plasticizer is called dope or enamel. Tsapon is more complex in composition. Overall this is a quality varnish.

Posted September 14 - You're right. The composition written on the bottle with zapon-varnish is organic solvents, acrylic copolymer. Designed for protective and decorative coatings of products made of ferrous and non-ferrous metals. For external and internal works. Nothing is said about UV resistance. All that remains is the felt boot. Number of users reading this topic: 0 0 users, 0 guests, 0 hidden users.

Help System for IP communities. Login Need an account? Register now! I forgot my password. Remember me This is not recommended for public computers.

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Antiquax Copper and Brass Polish

Source: https://all-audio.pro/c23/obsuzhdeniya/zashita-latuni-ot-potemneniya.php

How to protect brass from oxidation

Brass is a beautiful metal that attracts attention, but only if it is properly cared for. If you like brass products, it is important to care for them properly. Cleaning brass involves certain rules, if you break them you can say goodbye to your favorite item.

Brass Cleaning Options

Quite often, cleaning brass at home involves creating an acidic environment, because it is the oxides that create unpleasant darkening on the surface. The most popular remedy in this case is oxalic acid, although some believe that any product with a chemical composition that contains acid is available for use.

If you find a detergent containing oxalic acid in your bins, then cleaning the brass item will be easy.

It is enough to lubricate the product with a thick layer and leave for a short period of time. Do not be alarmed that a dark coating will appear during the washing process. To remove it, a brush and running water are enough.

After the product has been washed, cover it with a layer of soda, leaving it for a while, then rinse again under running water. Rub the item with a soft cloth until a characteristic shine appears.

If the pollution is “ingrained”, then it is better to prepare your own oxalic acid solution for work. For ten liters of water, 200 grams of acid are used. The contaminated product is placed in the acid solution. Do not forget about the possible darkening, which you should not be afraid of. Thanks to such a concentrated mixture, you can count on deep cleaning of the metal even from old stains. After the “bath”, send the product for washing, and then rub it properly.

Another chemical liquid ideal for working with brass is acetone. He is able to return it to its original appearance, and working with it is not difficult. It is enough to moisten a cotton swab in acetone and wipe the product until all stains are removed. This method of working is also relevant for copper products.

Folk recipes

Not everyone likes the idea of ​​cleaning products with chemicals, so you have to turn to folk recipes.

Toothpaste

When using toothpaste, first wash the product with soapy water, which will slightly soften old stains. Next, toothpaste is applied to problem areas, which are subsequently scrubbed off. You can use either a regular napkin or a toothbrush, which will allow you to work in hard-to-reach places.

Vinegar

The vinegar mixture will require flour and water. For a glass of any flour, use a glass of water and a glass of table vinegar (9 percent solution). The resulting mixture is rubbed tightly onto the product, after which the mixture must be given time to dry.

Usually this time period is enough for a stain of even high density to be dissolved with vinegar; the flour, in turn, will act as an absorbent agent. It will be enough to walk over the surface with a soft cloth.

If not all stains are removed the first time, repeat the procedure.

Lemon juice with salt

To polish using citrus juice and salt, you will need the juice of half a lemon, to which table salt is added little by little. The amount may vary, so it is important for you to bring the mixture to a paste. The resulting product is applied to the object, and the treatment is carried out with gentle movements in a circle. The remaining product is washed off with water, after which the product is dried with a dry soft cloth.

Soap solution

Soaking in a soap solution can be considered not only as an independent method of work, but also as a preparatory step, which is recommended for any of the above methods. If the stains are fresh, then one soap solution will be enough.

To work, warm water is poured into a basin, and shavings of laundry soap and any dishwashing detergent are dissolved in it. After preliminary foaming, the products are laid for several minutes until the liquid cools down.

After this, the water is drained, and the objects are treated with a soft bristle brush under running water.

Table vinegar

If the brass is covered with individual stains, then hot table vinegar will do the job. The pure product must be heated to a tolerable state. Next, soak a cotton pad in hot vinegar and use it to wipe off individual stains on the surface. If you choose this method, you will need a well-ventilated area to work, as the smell will be quite strong.

How to Protect Brass

In order not to think about emergency methods of cleaning brass items, it is enough to prevent the formation of stains. To do this, wipe the products with a clean cloth, onto which a small amount of olive oil is first applied. It is important to emphasize the word “small”. A thick layer of oil can ruin the polish, which can cause imprints.

To work, just lightly dip a clean, soft cloth in olive oil and transfer it to the surface of the product. Using another clean rag, spread the oil over the surface, which will act as a protective layer. This simple solution will prevent oxidation or minimize it.

Polishing

Polishing brass should be done after each cleaning of the product. You can use special polishes, rubbing them into the surface and then polishing with a soft cloth to the desired shine. Varnishing will also help. This procedure is important to maintain shine and provide reliable protection. It is important to apply the varnish layer evenly. To do this, you can choose a brush or cotton pads. After the varnishing process, it is mandatory to wipe the brass with any cloth.

Source: https://respect-kovka.com/kak-zaschitit-latun-ot-okisleniya/

About the oxidation of brass

Source: https://rus.roomsdecorating.com/about-brass-oxidation_24429

How to clean brass from oxides - Metalworker's Guide

How to clean brass from oxides - Metalworker's Guide

How to clean brass from oxides - Metalworker's Guide

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

How to clean metal from oxidation

How to clean metal from oxidation

How to clean metal from oxidation

How to clean copper? The relevance of this issue is explained by the fact that products made from this metal have been used by humanity for many centuries. For a long time, the value of this metal was so high that it was equal to gold.

The development of technology has led to the fact that it was possible to significantly reduce the cost of copper production. This made it possible to make not only jewelry from this metal, but also dishes and interior items.

The high popularity of this metal and alloys based on it is explained not only by its decorative effect, but also by its unique characteristics - high ductility, thermal conductivity, corrosion resistance, etc.

No one wants to use oxidized copper cookware.

Why copper products need to be cleaned regularly

How to protect copper from oxidation? — Machine tools, welding, metalworking

How to protect copper from oxidation? — Machine tools, welding, metalworking

How to protect copper from oxidation? — Machine tools, welding, metalworking

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

How copper corrosion occurs in water, alkali, and acid. Protection measures

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Does brass oxidize? — Metals, equipment, instructions

Anyone who searches for and sells non-ferrous metal sometimes has doubts about the type of scrap and, accordingly, its true value upon delivery.

Copper is a non-ferrous metal, and brass is an alloy that is typically 70% copper, so it often resembles it.

A mistake can be quite costly. For copper at collection points they give 285-300 rubles, for brass - about 150 . There are many ways to find out what kind of metal we see - copper or brass, and we will tell you how to distinguish them from each other in this article.

What is copper and brass

Search data for your request:

Moderators: shapanur, lomaster. Confidentiality Rules. Time: 0. Popular weapon. To finally, once and for all, part with the drive made of fucking aluminum, with which the fucking Ketais replaced noble brass. The cone end of the storage tank is covered with gray oxide that is difficult to remove; the pump pipe in the storage area is also oxidized

Search data for your request:

Schemes, reference books, datasheets: Discussions, articles, manuals:

Wait for the search to complete in all databases.
Upon completion, a link will appear to access the found materials.

How to protect brass from oxidation

Brass is a beautiful metal that attracts attention, but only if it is properly cared for. If you like brass products, it is important to care for them properly. Cleaning brass involves certain rules, if you break them you can say goodbye to your favorite item.

Brass Cleaning Options

About the oxidation of brass

Source: https://rus.roomsdecorating.com/about-brass-oxidation_24429

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

Cleaning brass at home is almost as easy as cleaning copper or bronze, but there are exceptions to this alloy.

In the step-by-step instructions with photos below, using a brass figurine as an example, we will explain how to properly clean the alloy yourself and what preliminary measures should be taken to avoid damaging the surface of the product.

1. First of all, it is necessary to determine the material from which the figurine is made. This is especially true if you do not remember whether it is brass or another metal. Externally, brass resembles gold, the alloy shines and has a not too rich yellow color. If you apply even the smallest magnet to the surface of the figurine, it will not stick. If the product is made of brass, then you should also understand that you can only clean and restore a figurine made of brass with a protective varnish layer. In another case, it is best not to waste time and effort, but to immediately take the product to a specialist.
2. Having decided on the alloy, you can now proceed directly to cleaning. We fill a basin with warm water and add dishwashing detergent to the liquid or rub a small piece of soap. We wipe the surface of the brass product with a flannel cloth, paying special attention to darkening.
3. We carefully wipe the brass figurine dry and proceed to the next stage of restoring the alloy. To do this, we cover the workspace with old newspapers. Armed with a brush, carefully remove the old varnish coating using a special liquid.
4. Once the protective varnish layer has been removed, the brass must be thoroughly polished. For this purpose it is also best to use a specially designed product.
5. We put on cotton gloves so as not to stain the polished brass, and at this stage we coat the product with a new layer of varnish to protect the alloy. The layer should be thin and uniform. Be sure to wait until the product is completely dry.
6. At the final stage, rub the surface of the brass, cleaned to a shine, with a microfiber cloth.

Such simple steps will allow you to restore a brass product if it is not too damaged. Incorrect or untimely care will result in the surface of a brass product, for example, a samovar, becoming covered with unpleasant oxide. In this case, you will have to resort to more serious cleaning of the alloy.

Household chemicals

How to clean metal from oxidation

How to clean copper? The relevance of this issue is explained by the fact that products made from this metal have been used by humanity for many centuries. For a long time, the value of this metal was so high that it was equal to gold.

The development of technology has led to the fact that it was possible to significantly reduce the cost of copper production. This made it possible to make not only jewelry from this metal, but also dishes and interior items.

The high popularity of this metal and alloys based on it is explained not only by its decorative effect, but also by its unique characteristics - high ductility, thermal conductivity, corrosion resistance, etc.

No one wants to use oxidized copper cookware.

Why copper products need to be cleaned regularly

Regular cleaning of copper utensils and other items made from this metal is necessary because during use they quickly darken or become covered with a green coating - an oxide film.

Those products made of copper and its alloys that are often heated during operation or used outdoors are the most actively oxidized.

Dishes made of copper, with active use, quickly lose their original shine and become dull; their surface may become black.

Copper jewelry behaves somewhat differently: it may first fade and lose its shine, and then return to its original appearance. Some people believe that the appearance of copper jewelry (for example, a bracelet) is influenced by the well-being of the person who constantly wears it.

However, this is most likely due to the fact that in the external environment with which such a product is constantly in contact, humidity, pressure and temperature are constantly changing.

Meanwhile, many adherents of alternative medicine recommend wearing copper bracelets for people experiencing problems with the cardiovascular system.

A rare samovar preserved from our great-grandfathers evokes something homely and dear

Copper utensils, which our distant ancestors began to use, are still held in high esteem by many housewives today.

This popularity is explained by the fact that in copper cookware, which is characterized by high thermal conductivity, all cooked products are heated evenly and in full, and such heating occurs in a short period of time.

Meanwhile, with constant use, dishes made of this metal quickly lose their visual appeal: they become covered with a coating of oxide, become dull, darken and lose their original shine.

If you do not clean it, it will release toxic substances, and therefore cannot be used for cooking.

If it is not possible to clean such dishes using all known means, it is better not to use them for their intended purpose, so as not to harm your health.

You should also keep in mind that dishes with black or green oxide spots on the surface look unpresentable, so they will not decorate your kitchen.

Effective cleaning methods

How to protect copper from oxidation? — Machine tools, welding, metalworking

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

How copper corrosion occurs in water, alkali, and acid. Protection measures

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

Corrosion of copper in the soil is mainly caused by the influence of acids contained in the soil. Compared with the effects of water, oxygen in the soil oxidizes metal elements much less. The most dangerous microorganisms in the soil are, or rather, their secretions. They are often capable of releasing hydrogen sulfide, which destroys metal. Thus, copper lying in the soil for a long time can completely decompose.

In humid air the process does not proceed rapidly. It takes a long time. In a dry climate, destructive effects may not be observed at all. This is explained by the fact that in humid air there is a high concentration of carbon dioxide, sulfides, chlorides, which cause corrosion and are destructive to the protective film.

Prolonged exposure to humid air can cause the formation of a patina layer. This is the name given to green deposits on copper. It consists of salt oxides, which are initially dark brown in color, and then the surface begins to turn green.

The peculiarity of patina is that it cannot be dissolved in water and is not affected by high air humidity. It has neutral properties to copper itself, which allows it to protect the surface from the harmful effects of the environment.

In addition, modern methods of creating artificial patina make it possible to use it in objects of art and during restoration.

Look at your personal experience in combating corrosion with the help of inhibitors.

Source: https://oxmetall.ru/metalli/med/kak-protekaet-korroziya-medi

Does brass oxidize? — Metals, equipment, instructions

Anyone who searches for and sells non-ferrous metal sometimes has doubts about the type of scrap and, accordingly, its true value upon delivery.

Copper is a non-ferrous metal, and brass is an alloy that is typically 70% copper, so it often resembles it.

A mistake can be quite costly. For copper at collection points they give 285-300 rubles, for brass - about 150 . There are many ways to find out what kind of metal we see - copper or brass, and we will tell you how to distinguish them from each other in this article.

What is copper and brass

Copper is a non-ferrous metal. Its color is reddish-pink, it is pliable when working, soft and malleable. It has high thermal and electrical conductivity, so copper is often used to produce:

• parts of electrical appliances;
• cables;
• radiators.

Copper is not hardened because it becomes hard even after cold forging. It tends to become covered with patina - a green coating that occurs when the ambient humidity is high.

https://www.youtube.com/watch?v=s2-0hGlxXgw

To increase strength, improve a number of other indicators and reduce the cost of the material, impurities are added and an alloy is obtained.

One such alloy is brass .

In the classic version it contains a third of zinc.

Brass is golden yellow, stronger and harder. It does not oxidize so intensively , and is not so plastic.

Sometimes, depending on the purpose of the alloy, they add:

• tin;
• silicon;
• lead;
• manganese.

Similarities and differences

Brass alloy consists mostly of copper, so it is natural that they are similar not only visually, but also in some properties. The more copper in the alloy, the more similar their colors will be. This is where the exact coincidences end.

Visually, less than 80% copper are easily distinguished . They are slightly similar to gold, as they have a pronounced yellow tint. The more zinc, the lighter the shade.

Because of this, brass is even used to counterfeit or imitate gold . Copper has a main shade of reddish, which often has a pink tint.

With a strong decrease in temperature, brass does not lose its relatively limited ductility and does not become brittle . Conducts electricity and heat worse.

They differ in such a way as hardness .

Copper is softer and more ductile , while brass, on the contrary, is hard and it is difficult to give it any shape without annealing.

The shavings are also different: for brass they are needle- shaped , for copper they are twisted into a spiral .

Let's look at the properties that brass and copper have and whether they have any differences:

Copper	Brass
Plastic, soft	Solid
Reddish-brown-pink tint	Golden tone
Lower sound on impact	Alt
Heavy	Easier
The shavings are twisted into a spiral	Needle shavings

Most often you can distinguish by:

• mind;
• weight;
• degree of hardness

without the use of any tools or equipment.

But there are situations when, for accuracy, it is necessary to use :

• reagents,
• tools,
• devices.

Before assessing the scrap that you are going to take to the collection point, you need to clean it of dirt, otherwise you won’t be able to accurately determine it by eye.

Both metals, although to varying degrees, can develop a patina .

Therefore, do not forget to clean the scrap well.

If an object has been in the open air or in water for a long time, the patina layer is difficult to remove.

Sometimes it will be justified to purchase a special cleaning product .

It is advisable to inspect the scrap under a powerful white light.

This implies that one can view either under the sun on a fine day or under a bright fluorescent lamp . Incandescent lamp is not suitable.

Pure copper will have a reddish-brown tint, sometimes with a pink tint. Keep in mind that brass can be red or orange. This type is commonly used for decorations and water pipes.

If the material has an orange, yellow or golden tint, you can be almost sure that it is brass.

Source: https://spb-metalloobrabotka.com/okislyaetsya-li-latun/

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WATCH THE VIDEO ON THE TOPIC: Polishing brass in St. Petersburg. Protection of brass from oxidation. all-audio.pro

Varnish for brass to prevent it from darkening

Skip to content. You have JavaScript disabled. Some functions may not work. Please enable JavaScript to access all features. Posted September 13 - Anyone know how to weatherproof it? A solution of celluloid in acetone and other solvents. Used to protect printed circuit boards. Not sure it will withstand weathering. Better than any regular waterproof varnish, starting with nitro.

You just need to properly degrease the surface and apply several layers so that it does not peel off and there are no cracks in the future.

Otherwise, everything will become covered with spots and mesh. Or maybe it can be laminated into film? Posted September 14 - HTML mode enabled. The visual editor is not available while HTML is enabled. You may lose some formatting when you turn off HTML mode and return to visual.

System for IP communities. Protection of brass Author Danev, September 13 Posted September 13 — Dear colleagues, Please share your experience. The editorial team had the conceit of making the “KYA” façade sign out of polished brass. Possibly tombaka.

So in some places it gradually darkens from the splashes of water, and our women do not like this. Or to nothing? Sent on September 13 - it is gradually darkening in places due to splashes of water.

There is an ancient method that has been tested for centuries. A watchman is appointed, who every morning walks over the brass with a piece of felt boots. It works radically!

Posted September 13 - Exactly. Asidol, GOI paste and a piece of an overcoat - “our” method! Don’t you now have an anchor on the pedestal in front of the entrance? Otherwise you need to sharpen it. Also regularly. Sent on September 13 - Give free rein to you, my darlings - we'll send the entire editorial staff to the pit. Apparently, Frum will have to do it like an old mechanic. Sent on September 13 - What about acrylic auto varnish?

Posted September 13 - Old anglers use passivation. For a sign, I don’t know, it’s a bit large. The recipe is this: Clean, polish, degrease. For 1 - 2 seconds, lower 1 part nitric acid and 1 part sulfuric acid into the solution. Immediately transfer chrompic into a saturated solution of potassium dichromate.

Keep for 10 - 15 minutes. Rinse and dry. The film is resistant and not afraid of moisture. Holds even in sea water. Well, or felt boots Posted on September 13 - Tsapon-lak. All varnishes on polished brass are highly visible. The appearance of the product is greatly inferior. In addition, they are short-lived. They become cloudy from ultraviolet radiation. They crack due to temperature changes. By the way, a solution of celluloid in acetone with a plasticizer is called dope or enamel. Tsapon is more complex in composition. Overall this is a quality varnish.

Posted September 14 - You're right. The composition written on the bottle with zapon-varnish is organic solvents, acrylic copolymer. Designed for protective and decorative coatings of products made of ferrous and non-ferrous metals. For external and internal works. Nothing is said about UV resistance. All that remains is the felt boot. Number of users reading this topic: 0 0 users, 0 guests, 0 hidden users.

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Antiquax Copper and Brass Polish

Source: https://all-audio.pro/c23/obsuzhdeniya/zashita-latuni-ot-potemneniya.php

How to protect brass from oxidation

Brass is a beautiful metal that attracts attention, but only if it is properly cared for. If you like brass products, it is important to care for them properly. Cleaning brass involves certain rules, if you break them you can say goodbye to your favorite item.

Brass Cleaning Options

Quite often, cleaning brass at home involves creating an acidic environment, because it is the oxides that create unpleasant darkening on the surface. The most popular remedy in this case is oxalic acid, although some believe that any product with a chemical composition that contains acid is available for use.

If you find a detergent containing oxalic acid in your bins, then cleaning the brass item will be easy.

It is enough to lubricate the product with a thick layer and leave for a short period of time. Do not be alarmed that a dark coating will appear during the washing process. To remove it, a brush and running water are enough.

After the product has been washed, cover it with a layer of soda, leaving it for a while, then rinse again under running water. Rub the item with a soft cloth until a characteristic shine appears.

If the pollution is “ingrained”, then it is better to prepare your own oxalic acid solution for work. For ten liters of water, 200 grams of acid are used. The contaminated product is placed in the acid solution. Do not forget about the possible darkening, which you should not be afraid of. Thanks to such a concentrated mixture, you can count on deep cleaning of the metal even from old stains. After the “bath”, send the product for washing, and then rub it properly.

Another chemical liquid ideal for working with brass is acetone. He is able to return it to its original appearance, and working with it is not difficult. It is enough to moisten a cotton swab in acetone and wipe the product until all stains are removed. This method of working is also relevant for copper products.

Folk recipes

Not everyone likes the idea of ​​cleaning products with chemicals, so you have to turn to folk recipes.

Toothpaste

When using toothpaste, first wash the product with soapy water, which will slightly soften old stains. Next, toothpaste is applied to problem areas, which are subsequently scrubbed off. You can use either a regular napkin or a toothbrush, which will allow you to work in hard-to-reach places.

Vinegar

The vinegar mixture will require flour and water. For a glass of any flour, use a glass of water and a glass of table vinegar (9 percent solution). The resulting mixture is rubbed tightly onto the product, after which the mixture must be given time to dry.

Usually this time period is enough for a stain of even high density to be dissolved with vinegar; the flour, in turn, will act as an absorbent agent. It will be enough to walk over the surface with a soft cloth.

If not all stains are removed the first time, repeat the procedure.

Lemon juice with salt

To polish using citrus juice and salt, you will need the juice of half a lemon, to which table salt is added little by little. The amount may vary, so it is important for you to bring the mixture to a paste. The resulting product is applied to the object, and the treatment is carried out with gentle movements in a circle. The remaining product is washed off with water, after which the product is dried with a dry soft cloth.

Soap solution

Soaking in a soap solution can be considered not only as an independent method of work, but also as a preparatory step, which is recommended for any of the above methods. If the stains are fresh, then one soap solution will be enough.

To work, warm water is poured into a basin, and shavings of laundry soap and any dishwashing detergent are dissolved in it. After preliminary foaming, the products are laid for several minutes until the liquid cools down.

After this, the water is drained, and the objects are treated with a soft bristle brush under running water.

Table vinegar

If the brass is covered with individual stains, then hot table vinegar will do the job. The pure product must be heated to a tolerable state. Next, soak a cotton pad in hot vinegar and use it to wipe off individual stains on the surface. If you choose this method, you will need a well-ventilated area to work, as the smell will be quite strong.

How to Protect Brass

In order not to think about emergency methods of cleaning brass items, it is enough to prevent the formation of stains. To do this, wipe the products with a clean cloth, onto which a small amount of olive oil is first applied. It is important to emphasize the word “small”. A thick layer of oil can ruin the polish, which can cause imprints.

To work, just lightly dip a clean, soft cloth in olive oil and transfer it to the surface of the product. Using another clean rag, spread the oil over the surface, which will act as a protective layer. This simple solution will prevent oxidation or minimize it.

Polishing

Polishing brass should be done after each cleaning of the product. You can use special polishes, rubbing them into the surface and then polishing with a soft cloth to the desired shine. Varnishing will also help. This procedure is important to maintain shine and provide reliable protection. It is important to apply the varnish layer evenly. To do this, you can choose a brush or cotton pads. After the varnishing process, it is mandatory to wipe the brass with any cloth.

Source: https://respect-kovka.com/kak-zaschitit-latun-ot-okisleniya/

About the oxidation of brass

Source: https://rus.roomsdecorating.com/about-brass-oxidation_24429

How to clean brass from oxides - Metalworker's Guide

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

Cleaning brass at home

Cleaning brass at home is almost as easy as cleaning copper or bronze, but there are exceptions to this alloy.

In the step-by-step instructions with photos below, using a brass figurine as an example, we will explain how to properly clean the alloy yourself and what preliminary measures should be taken to avoid damaging the surface of the product.

1. First of all, it is necessary to determine the material from which the figurine is made. This is especially true if you do not remember whether it is brass or another metal. Externally, brass resembles gold, the alloy shines and has a not too rich yellow color. If you apply even the smallest magnet to the surface of the figurine, it will not stick. If the product is made of brass, then you should also understand that you can only clean and restore a figurine made of brass with a protective varnish layer. In another case, it is best not to waste time and effort, but to immediately take the product to a specialist.
2. Having decided on the alloy, you can now proceed directly to cleaning. We fill a basin with warm water and add dishwashing detergent to the liquid or rub a small piece of soap. We wipe the surface of the brass product with a flannel cloth, paying special attention to darkening.
3. We carefully wipe the brass figurine dry and proceed to the next stage of restoring the alloy. To do this, we cover the workspace with old newspapers. Armed with a brush, carefully remove the old varnish coating using a special liquid.
4. Once the protective varnish layer has been removed, the brass must be thoroughly polished. For this purpose it is also best to use a specially designed product.
5. We put on cotton gloves so as not to stain the polished brass, and at this stage we coat the product with a new layer of varnish to protect the alloy. The layer should be thin and uniform. Be sure to wait until the product is completely dry.
6. At the final stage, rub the surface of the brass, cleaned to a shine, with a microfiber cloth.

Such simple steps will allow you to restore a brass product if it is not too damaged. Incorrect or untimely care will result in the surface of a brass product, for example, a samovar, becoming covered with unpleasant oxide. In this case, you will have to resort to more serious cleaning of the alloy.

Household chemicals

Household chemicals

On sale you can find household chemicals that are intended exclusively for cleaning brass products. The most common means of cleaning this alloy include:

• household chemicals that contain oxalic acid: just apply the purchased product to the degreased surface of the brass product, and then wait until the acid causes the alloy to become covered with a dark foam (it is easy to wash off the blackened layer under running water);
• Acetone can help remove oxide from the surface of brass; to do this, simply rub a swab dipped in liquid onto the contaminated surface of the brass product;
• toothpaste or powder will also work well to remove serious stains, although these substances are abrasives, they are quite safe to use on brass;
• sandpaper is the most extreme option; if the entire brass product is covered with a thick layer of plaque and oxide, you should act very carefully so as not to damage the alloy that is not affected by corrosion.

Remember! When working with oxalic acid and other aggressive household chemicals, be sure to follow safety precautions by wearing gloves and a respirator. Ventilate the area where you cleaned the brass for several hours.

You can learn how to restore brass at home using a creamy metal surface cleaner by watching the video below.

Folk remedies

Folk remedies

There are a lot of folk remedies for cleaning brass; for convenience, we have collected them in the table below.

Means	Mode of application
Lemon juice	Lemon juice effectively and safely cleans the surface of a brass product from oxide, and also restores the shine of the metal. For greater efficiency, you need to squeeze lemon juice into a small bowl, and then pour table salt into the liquid until the mixture has the consistency of sour cream. We use the prepared product and a soft sponge to clean brass. We process the surface in a circular motion until the layer of dirt begins to collapse. Afterwards, you only need to rinse the cutlery or any other brass items under running water.
Buttermilk	Few people know, but you can clean brass well from darkening using regular buttermilk. Pour about a liter of liquid into a basin, add two tablespoons of fine table salt, using a soft sponge, clean the brass and return the shine to the alloy. After the procedure, the product will need to be rinsed in warm water and wiped dry with a clean towel.
Wheat flour	To clean brass from oxide and darkening at home, it is enough to mix clean water and table vinegar in equal proportions. Wheat flour must be added to the resulting solution to form a paste-like mass. Carefully coat the entire surface of the brass product with the prepared dough, and then wait until the mixture is completely dry. The acid will react with the contamination, and the dough will absorb all the secretions. Afterwards, it will be enough to thoroughly rinse the brass under running water and wipe the surface dry with a towel.
Table vinegar	In case of serious contamination, you can try using the following detergent. Choose a container that you don’t mind spoiling. Pour vinegar into the selected pan and bring the liquid to a boil. Immerse the brass product in boiling vinegar or wipe the oxidized surface with the solution. If the metal has recently been corroded, this product will be very effective.
Baking soda and laundry soap	Last in the table, but not the most effective, is a cleaning product made from baking soda and laundry soap. We'll actually be using the boiling method, which is ideal for copper. Since brass is an alloy of copper, the method will also be effective in this case. We fill a large saucepan with water, rub half of the laundry soap into it and add a few tablespoons of baking soda. Bring the liquid to a boil. We lower the brass into the boiling solution for a while until the contamination is cleared. After this, be sure to replace the varnish coating.

You can also use ketchup, yogurt or white vinegar to clean brass at home. Such products are not very effective, but they will help you quickly deal with minor stains. When cleaning, do not use too much physical force to scrub away dirt. In this way, you can wipe off not only a layer of dirt, but also a layer of original paint on a brass product.

Preventative care

Preventative care

To avoid having to wonder how to clean brass from stains and restore the shine of the product, it is enough to perform preventative cleaning of the alloy. The following tips will help you keep your brass in tip-top condition at all times:

• Dry clean brass products regularly, do not allow dust to accumulate in places that are inaccessible for thorough cleaning;
• brass and other alloys do not withstand ultraviolet radiation very well, so samovars and kitchen utensils made from this alloy are best stored in chests of drawers and drawers;
• do not allow increased humidity in the room where brass is stored;
• store jewelry made of copper, brass and bronze separately from each other in special boxes or cases, which are lined with soft fabric on the inside;
• polish brass products with special products: this way the metal will always remain light and shiny.

Caring for products made from various alloys is quite simple, but many people neglect even regular dry cleaning, so they have to look for ways to clean oxide and dark spots.

Even if you don't know it, there may be quite a few brass items in your apartment.

These include candlesticks, metal chandelier inserts, picture frames, antique samovars, teapots and pots, cutlery, vases and pots, taps and decorative figurines. It is very important to take care of brass products so that they are always clean.

  Brass melting temperature

The presented material contains all the necessary information on how and with what you can clean and restore brass at home quickly, simply and effectively. After cleaning, all that remains is to maintain cleanliness and properly store brass products.

Similar materials

Similar materials

Storing blanketsDry cleaning clothesHow to wash pomegranate?

Source: https://ssk2121.com/chem-chistit-latun-ot-okislov/

How to clean metal from oxidation

How to clean metal from oxidation

How to clean copper? The relevance of this issue is explained by the fact that products made from this metal have been used by humanity for many centuries. For a long time, the value of this metal was so high that it was equal to gold.

The development of technology has led to the fact that it was possible to significantly reduce the cost of copper production. This made it possible to make not only jewelry from this metal, but also dishes and interior items.

The high popularity of this metal and alloys based on it is explained not only by its decorative effect, but also by its unique characteristics - high ductility, thermal conductivity, corrosion resistance, etc.

No one wants to use oxidized copper cookware.

Why copper products need to be cleaned regularly

Why copper products need to be cleaned regularly

Regular cleaning of copper utensils and other items made from this metal is necessary because during use they quickly darken or become covered with a green coating - an oxide film.

Those products made of copper and its alloys that are often heated during operation or used outdoors are the most actively oxidized.

Dishes made of copper, with active use, quickly lose their original shine and become dull; their surface may become black.

Copper jewelry behaves somewhat differently: it may first fade and lose its shine, and then return to its original appearance. Some people believe that the appearance of copper jewelry (for example, a bracelet) is influenced by the well-being of the person who constantly wears it.

However, this is most likely due to the fact that in the external environment with which such a product is constantly in contact, humidity, pressure and temperature are constantly changing.

Meanwhile, many adherents of alternative medicine recommend wearing copper bracelets for people experiencing problems with the cardiovascular system.

A rare samovar preserved from our great-grandfathers evokes something homely and dear

Copper utensils, which our distant ancestors began to use, are still held in high esteem by many housewives today.

This popularity is explained by the fact that in copper cookware, which is characterized by high thermal conductivity, all cooked products are heated evenly and in full, and such heating occurs in a short period of time.

Meanwhile, with constant use, dishes made of this metal quickly lose their visual appeal: they become covered with a coating of oxide, become dull, darken and lose their original shine.

If you do not clean it, it will release toxic substances, and therefore cannot be used for cooking.

If it is not possible to clean such dishes using all known means, it is better not to use them for their intended purpose, so as not to harm your health.

You should also keep in mind that dishes with black or green oxide spots on the surface look unpresentable, so they will not decorate your kitchen.

Effective cleaning methods

Effective cleaning methods

There are many proven methods that allow you to clean copper products even at home. Let's get acquainted with the most effective of them.

Method No. 1

One of the most accessible home remedies for cleaning objects made of copper is regular tomato ketchup. In order to clean copper with this product, it is simply applied to the surface to be treated and left on it for 1-2 minutes. After this exposure, the ketchup is washed off with a stream of warm water. As a result of this procedure, the copper product will return to its original shine and brightness of color.

Ketchup as a cleaning agent

Method No. 2

You can clean copper items, if they are not very dirty, at home using regular dishwashing gel. To do this, use a soft sponge on which detergent is applied. Wash it off under running warm water.

For slightly tarnished copper items, try washing them as normal dishes.

Method No. 3

This cleaning method is used if it is necessary to clean a large copper product that cannot be placed in any container. The surface of such an object is wiped with half a lemon. To enhance the effect of lemon juice on copper, you can clean it with a brush with bristles that have sufficient elasticity.

Method No. 4

A product called “vinegar paste” helps give copper its former shine. It is prepared as follows. In a special container, mix wheat flour and vinegar in equal proportions, bringing the resulting mass to a homogeneous state. Then the dough is applied to a copper object and left until completely dry. The crust formed after the mixture has dried is carefully removed, and the copper surface is polished to a shine with a piece of soft cloth.

Method No. 5

Vinegar, salt and heat together will help clean tough stains.

There is a radical and effective method of cleaning products made of copper, which is used if their surface is heavily soiled and it was not possible to clean them with other means.

• Vinegar is poured into a specially prepared stainless steel container, which is mixed with a small amount of table salt.
• Place the item to be cleaned into the resulting solution and place the container on the fire.
• After the cleaning solution has reached a boil, turn off the heat under the container and leave it on the stove until it cools completely.
• After the solution has cooled, the product to be cleaned is removed, washed under running warm water and its surface wiped dry.

If you clean copper using any of the above methods, strictly adhere to safety rules, carry out all work wearing protective gloves, and be sure to wear a respirator when working with acetic acid.

Cleaning Copper Coins

Cleaning Copper Coins

Coins made of copper are no longer issued in our time, and many such products in the hands of the population are of antique value. That is why the question of how to effectively and at the same time carefully clean such coins is quite relevant.

You can restore the former attractiveness of copper coins using several methods. The choice of each of them depends on the nature and degree of contamination. So, depending on what color the plaque has formed on the surface of the old copper coin, you can clean it using one of the methods listed below.

• If there is a yellowish coating on the surface of the coin (this indicates that it has been in contact with a lead product), then it should be cleaned with a 9% vinegar solution.
• Clearly green plaque is cleaned with a 10% citric acid solution.
• Coins made from copper may also have a reddish coating. Such a coin is cleaned by dipping it in a 5% ammonia solution or ammonium carbonate.

Calculate the use of chemicals depending on the degree of contamination

Old coins made from copper may have a layer of patina, which gives them a more noble and aged appearance. If there is no such plaque, you can create it yourself, even at home. To do this, use a solution consisting of a liter of distilled water, 50 grams of copper sulfate and 5 grams of potassium permanganate.

The resulting solution is heated over low heat, without bringing it to a boil, and then coins are placed in it, which must be covered with a layer of patina. They are periodically turned over, and when the color of their surface acquires the desired shade, they are removed.

Source: https://steelfactoryrus.com/kak-ochistit-metall-ot-okisleniya/

How to protect copper from oxidation? — Machine tools, welding, metalworking

How to protect copper from oxidation? — Machine tools, welding, metalworking

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

How copper corrosion occurs in water, alkali, and acid. Protection measures

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

Corrosion of copper in the soil is mainly caused by the influence of acids contained in the soil. Compared with the effects of water, oxygen in the soil oxidizes metal elements much less. The most dangerous microorganisms in the soil are, or rather, their secretions. They are often capable of releasing hydrogen sulfide, which destroys metal. Thus, copper lying in the soil for a long time can completely decompose.

In humid air the process does not proceed rapidly. It takes a long time. In a dry climate, destructive effects may not be observed at all. This is explained by the fact that in humid air there is a high concentration of carbon dioxide, sulfides, chlorides, which cause corrosion and are destructive to the protective film.

Prolonged exposure to humid air can cause the formation of a patina layer. This is the name given to green deposits on copper. It consists of salt oxides, which are initially dark brown in color, and then the surface begins to turn green.

The peculiarity of patina is that it cannot be dissolved in water and is not affected by high air humidity. It has neutral properties to copper itself, which allows it to protect the surface from the harmful effects of the environment.

In addition, modern methods of creating artificial patina make it possible to use it in objects of art and during restoration.

Look at your personal experience in combating corrosion with the help of inhibitors.

Source: https://oxmetall.ru/metalli/med/kak-protekaet-korroziya-medi

Does brass oxidize? — Metals, equipment, instructions

Anyone who searches for and sells non-ferrous metal sometimes has doubts about the type of scrap and, accordingly, its true value upon delivery.

Copper is a non-ferrous metal, and brass is an alloy that is typically 70% copper, so it often resembles it.

A mistake can be quite costly. For copper at collection points they give 285-300 rubles, for brass - about 150 . There are many ways to find out what kind of metal we see - copper or brass, and we will tell you how to distinguish them from each other in this article.

What is copper and brass

Copper is a non-ferrous metal. Its color is reddish-pink, it is pliable when working, soft and malleable. It has high thermal and electrical conductivity, so copper is often used to produce:

• parts of electrical appliances;
• cables;
• radiators.

Copper is not hardened because it becomes hard even after cold forging. It tends to become covered with patina - a green coating that occurs when the ambient humidity is high.

https://www.youtube.com/watch?v=s2-0hGlxXgw

To increase strength, improve a number of other indicators and reduce the cost of the material, impurities are added and an alloy is obtained.

One such alloy is brass .

In the classic version it contains a third of zinc.

Brass is golden yellow, stronger and harder. It does not oxidize so intensively , and is not so plastic.

Sometimes, depending on the purpose of the alloy, they add:

• tin;
• silicon;
• lead;
• manganese.

Similarities and differences

Brass alloy consists mostly of copper, so it is natural that they are similar not only visually, but also in some properties. The more copper in the alloy, the more similar their colors will be. This is where the exact coincidences end.

Visually, less than 80% copper are easily distinguished . They are slightly similar to gold, as they have a pronounced yellow tint. The more zinc, the lighter the shade.

Because of this, brass is even used to counterfeit or imitate gold . Copper has a main shade of reddish, which often has a pink tint.

With a strong decrease in temperature, brass does not lose its relatively limited ductility and does not become brittle . Conducts electricity and heat worse.

They differ in such a way as hardness .

Copper is softer and more ductile , while brass, on the contrary, is hard and it is difficult to give it any shape without annealing.

The shavings are also different: for brass they are needle- shaped , for copper they are twisted into a spiral .

Let's look at the properties that brass and copper have and whether they have any differences:

Copper	Brass
Plastic, soft	Solid
Reddish-brown-pink tint	Golden tone
Lower sound on impact	Alt
Heavy	Easier
The shavings are twisted into a spiral	Needle shavings

Most often you can distinguish by:

• mind;
• weight;
• degree of hardness

without the use of any tools or equipment.

But there are situations when, for accuracy, it is necessary to use :

• reagents,
• tools,
• devices.

Before assessing the scrap that you are going to take to the collection point, you need to clean it of dirt, otherwise you won’t be able to accurately determine it by eye.

Both metals, although to varying degrees, can develop a patina .

Therefore, do not forget to clean the scrap well.

If an object has been in the open air or in water for a long time, the patina layer is difficult to remove.

Sometimes it will be justified to purchase a special cleaning product .

It is advisable to inspect the scrap under a powerful white light.

This implies that one can view either under the sun on a fine day or under a bright fluorescent lamp . Incandescent lamp is not suitable.

Pure copper will have a reddish-brown tint, sometimes with a pink tint. Keep in mind that brass can be red or orange. This type is commonly used for decorations and water pipes.

If the material has an orange, yellow or golden tint, you can be almost sure that it is brass.

Source: https://spb-metalloobrabotka.com/okislyaetsya-li-latun/

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WATCH THE VIDEO ON THE TOPIC: Polishing brass in St. Petersburg. Protection of brass from oxidation. all-audio.pro

Varnish for brass to prevent it from darkening

Skip to content. You have JavaScript disabled. Some functions may not work. Please enable JavaScript to access all features. Posted September 13 - Anyone know how to weatherproof it? A solution of celluloid in acetone and other solvents. Used to protect printed circuit boards. Not sure it will withstand weathering. Better than any regular waterproof varnish, starting with nitro.

You just need to properly degrease the surface and apply several layers so that it does not peel off and there are no cracks in the future.

Otherwise, everything will become covered with spots and mesh. Or maybe it can be laminated into film? Posted September 14 - HTML mode enabled. The visual editor is not available while HTML is enabled. You may lose some formatting when you turn off HTML mode and return to visual.

System for IP communities. Protection of brass Author Danev, September 13 Posted September 13 — Dear colleagues, Please share your experience. The editorial team had the conceit of making the “KYA” façade sign out of polished brass. Possibly tombaka.

So in some places it gradually darkens from the splashes of water, and our women do not like this. Or to nothing? Sent on September 13 - it is gradually darkening in places due to splashes of water.

There is an ancient method that has been tested for centuries. A watchman is appointed, who every morning walks over the brass with a piece of felt boots. It works radically!

Posted September 13 - Exactly. Asidol, GOI paste and a piece of an overcoat - “our” method! Don’t you now have an anchor on the pedestal in front of the entrance? Otherwise you need to sharpen it. Also regularly. Sent on September 13 - Give free rein to you, my darlings - we'll send the entire editorial staff to the pit. Apparently, Frum will have to do it like an old mechanic. Sent on September 13 - What about acrylic auto varnish?

Posted September 13 - Old anglers use passivation. For a sign, I don’t know, it’s a bit large. The recipe is this: Clean, polish, degrease. For 1 - 2 seconds, lower 1 part nitric acid and 1 part sulfuric acid into the solution. Immediately transfer chrompic into a saturated solution of potassium dichromate.

Keep for 10 - 15 minutes. Rinse and dry. The film is resistant and not afraid of moisture. Holds even in sea water. Well, or felt boots Posted on September 13 - Tsapon-lak. All varnishes on polished brass are highly visible. The appearance of the product is greatly inferior. In addition, they are short-lived. They become cloudy from ultraviolet radiation. They crack due to temperature changes. By the way, a solution of celluloid in acetone with a plasticizer is called dope or enamel. Tsapon is more complex in composition. Overall this is a quality varnish.

Posted September 14 - You're right. The composition written on the bottle with zapon-varnish is organic solvents, acrylic copolymer. Designed for protective and decorative coatings of products made of ferrous and non-ferrous metals. For external and internal works. Nothing is said about UV resistance. All that remains is the felt boot. Number of users reading this topic: 0 0 users, 0 guests, 0 hidden users.

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Antiquax Copper and Brass Polish

Source: https://all-audio.pro/c23/obsuzhdeniya/zashita-latuni-ot-potemneniya.php

How to protect brass from oxidation

Brass is a beautiful metal that attracts attention, but only if it is properly cared for. If you like brass products, it is important to care for them properly. Cleaning brass involves certain rules, if you break them you can say goodbye to your favorite item.

Brass Cleaning Options

Quite often, cleaning brass at home involves creating an acidic environment, because it is the oxides that create unpleasant darkening on the surface. The most popular remedy in this case is oxalic acid, although some believe that any product with a chemical composition that contains acid is available for use.

If you find a detergent containing oxalic acid in your bins, then cleaning the brass item will be easy.

It is enough to lubricate the product with a thick layer and leave for a short period of time. Do not be alarmed that a dark coating will appear during the washing process. To remove it, a brush and running water are enough.

After the product has been washed, cover it with a layer of soda, leaving it for a while, then rinse again under running water. Rub the item with a soft cloth until a characteristic shine appears.

If the pollution is “ingrained”, then it is better to prepare your own oxalic acid solution for work. For ten liters of water, 200 grams of acid are used. The contaminated product is placed in the acid solution. Do not forget about the possible darkening, which you should not be afraid of. Thanks to such a concentrated mixture, you can count on deep cleaning of the metal even from old stains. After the “bath”, send the product for washing, and then rub it properly.

Another chemical liquid ideal for working with brass is acetone. He is able to return it to its original appearance, and working with it is not difficult. It is enough to moisten a cotton swab in acetone and wipe the product until all stains are removed. This method of working is also relevant for copper products.

Folk recipes

Not everyone likes the idea of ​​cleaning products with chemicals, so you have to turn to folk recipes.

Toothpaste

When using toothpaste, first wash the product with soapy water, which will slightly soften old stains. Next, toothpaste is applied to problem areas, which are subsequently scrubbed off. You can use either a regular napkin or a toothbrush, which will allow you to work in hard-to-reach places.

Vinegar

The vinegar mixture will require flour and water. For a glass of any flour, use a glass of water and a glass of table vinegar (9 percent solution). The resulting mixture is rubbed tightly onto the product, after which the mixture must be given time to dry.

Usually this time period is enough for a stain of even high density to be dissolved with vinegar; the flour, in turn, will act as an absorbent agent. It will be enough to walk over the surface with a soft cloth.

If not all stains are removed the first time, repeat the procedure.

Lemon juice with salt

To polish using citrus juice and salt, you will need the juice of half a lemon, to which table salt is added little by little. The amount may vary, so it is important for you to bring the mixture to a paste. The resulting product is applied to the object, and the treatment is carried out with gentle movements in a circle. The remaining product is washed off with water, after which the product is dried with a dry soft cloth.

Soap solution

Soaking in a soap solution can be considered not only as an independent method of work, but also as a preparatory step, which is recommended for any of the above methods. If the stains are fresh, then one soap solution will be enough.

To work, warm water is poured into a basin, and shavings of laundry soap and any dishwashing detergent are dissolved in it. After preliminary foaming, the products are laid for several minutes until the liquid cools down.

After this, the water is drained, and the objects are treated with a soft bristle brush under running water.

Table vinegar

If the brass is covered with individual stains, then hot table vinegar will do the job. The pure product must be heated to a tolerable state. Next, soak a cotton pad in hot vinegar and use it to wipe off individual stains on the surface. If you choose this method, you will need a well-ventilated area to work, as the smell will be quite strong.

How to Protect Brass

In order not to think about emergency methods of cleaning brass items, it is enough to prevent the formation of stains. To do this, wipe the products with a clean cloth, onto which a small amount of olive oil is first applied. It is important to emphasize the word “small”. A thick layer of oil can ruin the polish, which can cause imprints.

To work, just lightly dip a clean, soft cloth in olive oil and transfer it to the surface of the product. Using another clean rag, spread the oil over the surface, which will act as a protective layer. This simple solution will prevent oxidation or minimize it.

Polishing

Polishing brass should be done after each cleaning of the product. You can use special polishes, rubbing them into the surface and then polishing with a soft cloth to the desired shine. Varnishing will also help. This procedure is important to maintain shine and provide reliable protection. It is important to apply the varnish layer evenly. To do this, you can choose a brush or cotton pads. After the varnishing process, it is mandatory to wipe the brass with any cloth.

Source: https://respect-kovka.com/kak-zaschitit-latun-ot-okisleniya/

About the oxidation of brass

Source: https://rus.roomsdecorating.com/about-brass-oxidation_24429

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

Cleaning brass at home is almost as easy as cleaning copper or bronze, but there are exceptions to this alloy.

In the step-by-step instructions with photos below, using a brass figurine as an example, we will explain how to properly clean the alloy yourself and what preliminary measures should be taken to avoid damaging the surface of the product.

1. First of all, it is necessary to determine the material from which the figurine is made. This is especially true if you do not remember whether it is brass or another metal. Externally, brass resembles gold, the alloy shines and has a not too rich yellow color. If you apply even the smallest magnet to the surface of the figurine, it will not stick. If the product is made of brass, then you should also understand that you can only clean and restore a figurine made of brass with a protective varnish layer. In another case, it is best not to waste time and effort, but to immediately take the product to a specialist.
2. Having decided on the alloy, you can now proceed directly to cleaning. We fill a basin with warm water and add dishwashing detergent to the liquid or rub a small piece of soap. We wipe the surface of the brass product with a flannel cloth, paying special attention to darkening.
3. We carefully wipe the brass figurine dry and proceed to the next stage of restoring the alloy. To do this, we cover the workspace with old newspapers. Armed with a brush, carefully remove the old varnish coating using a special liquid.
4. Once the protective varnish layer has been removed, the brass must be thoroughly polished. For this purpose it is also best to use a specially designed product.
5. We put on cotton gloves so as not to stain the polished brass, and at this stage we coat the product with a new layer of varnish to protect the alloy. The layer should be thin and uniform. Be sure to wait until the product is completely dry.
6. At the final stage, rub the surface of the brass, cleaned to a shine, with a microfiber cloth.

Such simple steps will allow you to restore a brass product if it is not too damaged. Incorrect or untimely care will result in the surface of a brass product, for example, a samovar, becoming covered with unpleasant oxide. In this case, you will have to resort to more serious cleaning of the alloy.

Household chemicals

On sale you can find household chemicals that are intended exclusively for cleaning brass products. The most common means of cleaning this alloy include:

• household chemicals that contain oxalic acid: just apply the purchased product to the degreased surface of the brass product, and then wait until the acid causes the alloy to become covered with a dark foam (it is easy to wash off the blackened layer under running water);
• Acetone can help remove oxide from the surface of brass; to do this, simply rub a swab dipped in liquid onto the contaminated surface of the brass product;
• toothpaste or powder will also work well to remove serious stains, although these substances are abrasives, they are quite safe to use on brass;
• sandpaper is the most extreme option; if the entire brass product is covered with a thick layer of plaque and oxide, you should act very carefully so as not to damage the alloy that is not affected by corrosion.

Remember! When working with oxalic acid and other aggressive household chemicals, be sure to follow safety precautions by wearing gloves and a respirator. Ventilate the area where you cleaned the brass for several hours.

You can learn how to restore brass at home using a creamy metal surface cleaner by watching the video below.

Folk remedies

There are a lot of folk remedies for cleaning brass; for convenience, we have collected them in the table below.

Means	Mode of application
Lemon juice	Lemon juice effectively and safely cleans the surface of a brass product from oxide, and also restores the shine of the metal. For greater efficiency, you need to squeeze lemon juice into a small bowl, and then pour table salt into the liquid until the mixture has the consistency of sour cream. We use the prepared product and a soft sponge to clean brass. We process the surface in a circular motion until the layer of dirt begins to collapse. Afterwards, you only need to rinse the cutlery or any other brass items under running water.
Buttermilk	Few people know, but you can clean brass well from darkening using regular buttermilk. Pour about a liter of liquid into a basin, add two tablespoons of fine table salt, using a soft sponge, clean the brass and return the shine to the alloy. After the procedure, the product will need to be rinsed in warm water and wiped dry with a clean towel.
Wheat flour	To clean brass from oxide and darkening at home, it is enough to mix clean water and table vinegar in equal proportions. Wheat flour must be added to the resulting solution to form a paste-like mass. Carefully coat the entire surface of the brass product with the prepared dough, and then wait until the mixture is completely dry. The acid will react with the contamination, and the dough will absorb all the secretions. Afterwards, it will be enough to thoroughly rinse the brass under running water and wipe the surface dry with a towel.
Table vinegar	In case of serious contamination, you can try using the following detergent. Choose a container that you don’t mind spoiling. Pour vinegar into the selected pan and bring the liquid to a boil. Immerse the brass product in boiling vinegar or wipe the oxidized surface with the solution. If the metal has recently been corroded, this product will be very effective.
Baking soda and laundry soap	Last in the table, but not the most effective, is a cleaning product made from baking soda and laundry soap. We'll actually be using the boiling method, which is ideal for copper. Since brass is an alloy of copper, the method will also be effective in this case. We fill a large saucepan with water, rub half of the laundry soap into it and add a few tablespoons of baking soda. Bring the liquid to a boil. We lower the brass into the boiling solution for a while until the contamination is cleared. After this, be sure to replace the varnish coating.

You can also use ketchup, yogurt or white vinegar to clean brass at home. Such products are not very effective, but they will help you quickly deal with minor stains. When cleaning, do not use too much physical force to scrub away dirt. In this way, you can wipe off not only a layer of dirt, but also a layer of original paint on a brass product.

Preventative care

To avoid having to wonder how to clean brass from stains and restore the shine of the product, it is enough to perform preventative cleaning of the alloy. The following tips will help you keep your brass in tip-top condition at all times:

• Dry clean brass products regularly, do not allow dust to accumulate in places that are inaccessible for thorough cleaning;
• brass and other alloys do not withstand ultraviolet radiation very well, so samovars and kitchen utensils made from this alloy are best stored in chests of drawers and drawers;
• do not allow increased humidity in the room where brass is stored;
• store jewelry made of copper, brass and bronze separately from each other in special boxes or cases, which are lined with soft fabric on the inside;
• polish brass products with special products: this way the metal will always remain light and shiny.

Caring for products made from various alloys is quite simple, but many people neglect even regular dry cleaning, so they have to look for ways to clean oxide and dark spots.

Even if you don't know it, there may be quite a few brass items in your apartment.

These include candlesticks, metal chandelier inserts, picture frames, antique samovars, teapots and pots, cutlery, vases and pots, taps and decorative figurines. It is very important to take care of brass products so that they are always clean.

  Brass melting temperature

The presented material contains all the necessary information on how and with what you can clean and restore brass at home quickly, simply and effectively. After cleaning, all that remains is to maintain cleanliness and properly store brass products.

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Source: https://ssk2121.com/chem-chistit-latun-ot-okislov/

How to clean metal from oxidation

How to clean copper? The relevance of this issue is explained by the fact that products made from this metal have been used by humanity for many centuries. For a long time, the value of this metal was so high that it was equal to gold.

The development of technology has led to the fact that it was possible to significantly reduce the cost of copper production. This made it possible to make not only jewelry from this metal, but also dishes and interior items.

The high popularity of this metal and alloys based on it is explained not only by its decorative effect, but also by its unique characteristics - high ductility, thermal conductivity, corrosion resistance, etc.

No one wants to use oxidized copper cookware.

Why copper products need to be cleaned regularly

Regular cleaning of copper utensils and other items made from this metal is necessary because during use they quickly darken or become covered with a green coating - an oxide film.

Those products made of copper and its alloys that are often heated during operation or used outdoors are the most actively oxidized.

Dishes made of copper, with active use, quickly lose their original shine and become dull; their surface may become black.

Copper jewelry behaves somewhat differently: it may first fade and lose its shine, and then return to its original appearance. Some people believe that the appearance of copper jewelry (for example, a bracelet) is influenced by the well-being of the person who constantly wears it.

However, this is most likely due to the fact that in the external environment with which such a product is constantly in contact, humidity, pressure and temperature are constantly changing.

Meanwhile, many adherents of alternative medicine recommend wearing copper bracelets for people experiencing problems with the cardiovascular system.

A rare samovar preserved from our great-grandfathers evokes something homely and dear

Copper utensils, which our distant ancestors began to use, are still held in high esteem by many housewives today.

This popularity is explained by the fact that in copper cookware, which is characterized by high thermal conductivity, all cooked products are heated evenly and in full, and such heating occurs in a short period of time.

Meanwhile, with constant use, dishes made of this metal quickly lose their visual appeal: they become covered with a coating of oxide, become dull, darken and lose their original shine.

If you do not clean it, it will release toxic substances, and therefore cannot be used for cooking.

If it is not possible to clean such dishes using all known means, it is better not to use them for their intended purpose, so as not to harm your health.

You should also keep in mind that dishes with black or green oxide spots on the surface look unpresentable, so they will not decorate your kitchen.

Effective cleaning methods

There are many proven methods that allow you to clean copper products even at home. Let's get acquainted with the most effective of them.

Method No. 1

One of the most accessible home remedies for cleaning objects made of copper is regular tomato ketchup. In order to clean copper with this product, it is simply applied to the surface to be treated and left on it for 1-2 minutes. After this exposure, the ketchup is washed off with a stream of warm water. As a result of this procedure, the copper product will return to its original shine and brightness of color.

Ketchup as a cleaning agent

Method No. 2

You can clean copper items, if they are not very dirty, at home using regular dishwashing gel. To do this, use a soft sponge on which detergent is applied. Wash it off under running warm water.

For slightly tarnished copper items, try washing them as normal dishes.

Method No. 3

This cleaning method is used if it is necessary to clean a large copper product that cannot be placed in any container. The surface of such an object is wiped with half a lemon. To enhance the effect of lemon juice on copper, you can clean it with a brush with bristles that have sufficient elasticity.

Method No. 4

A product called “vinegar paste” helps give copper its former shine. It is prepared as follows. In a special container, mix wheat flour and vinegar in equal proportions, bringing the resulting mass to a homogeneous state. Then the dough is applied to a copper object and left until completely dry. The crust formed after the mixture has dried is carefully removed, and the copper surface is polished to a shine with a piece of soft cloth.

Method No. 5

Vinegar, salt and heat together will help clean tough stains.

There is a radical and effective method of cleaning products made of copper, which is used if their surface is heavily soiled and it was not possible to clean them with other means.

• Vinegar is poured into a specially prepared stainless steel container, which is mixed with a small amount of table salt.
• Place the item to be cleaned into the resulting solution and place the container on the fire.
• After the cleaning solution has reached a boil, turn off the heat under the container and leave it on the stove until it cools completely.
• After the solution has cooled, the product to be cleaned is removed, washed under running warm water and its surface wiped dry.

If you clean copper using any of the above methods, strictly adhere to safety rules, carry out all work wearing protective gloves, and be sure to wear a respirator when working with acetic acid.

Cleaning Copper Coins

Coins made of copper are no longer issued in our time, and many such products in the hands of the population are of antique value. That is why the question of how to effectively and at the same time carefully clean such coins is quite relevant.

You can restore the former attractiveness of copper coins using several methods. The choice of each of them depends on the nature and degree of contamination. So, depending on what color the plaque has formed on the surface of the old copper coin, you can clean it using one of the methods listed below.

• If there is a yellowish coating on the surface of the coin (this indicates that it has been in contact with a lead product), then it should be cleaned with a 9% vinegar solution.
• Clearly green plaque is cleaned with a 10% citric acid solution.
• Coins made from copper may also have a reddish coating. Such a coin is cleaned by dipping it in a 5% ammonia solution or ammonium carbonate.

Calculate the use of chemicals depending on the degree of contamination

Old coins made from copper may have a layer of patina, which gives them a more noble and aged appearance. If there is no such plaque, you can create it yourself, even at home. To do this, use a solution consisting of a liter of distilled water, 50 grams of copper sulfate and 5 grams of potassium permanganate.

The resulting solution is heated over low heat, without bringing it to a boil, and then coins are placed in it, which must be covered with a layer of patina. They are periodically turned over, and when the color of their surface acquires the desired shade, they are removed.

Source: https://steelfactoryrus.com/kak-ochistit-metall-ot-okisleniya/

How to protect copper from oxidation? — Machine tools, welding, metalworking

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

How copper corrosion occurs in water, alkali, and acid. Protection measures

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

Corrosion of copper in the soil is mainly caused by the influence of acids contained in the soil. Compared with the effects of water, oxygen in the soil oxidizes metal elements much less. The most dangerous microorganisms in the soil are, or rather, their secretions. They are often capable of releasing hydrogen sulfide, which destroys metal. Thus, copper lying in the soil for a long time can completely decompose.

In humid air the process does not proceed rapidly. It takes a long time. In a dry climate, destructive effects may not be observed at all. This is explained by the fact that in humid air there is a high concentration of carbon dioxide, sulfides, chlorides, which cause corrosion and are destructive to the protective film.

Prolonged exposure to humid air can cause the formation of a patina layer. This is the name given to green deposits on copper. It consists of salt oxides, which are initially dark brown in color, and then the surface begins to turn green.

The peculiarity of patina is that it cannot be dissolved in water and is not affected by high air humidity. It has neutral properties to copper itself, which allows it to protect the surface from the harmful effects of the environment.

In addition, modern methods of creating artificial patina make it possible to use it in objects of art and during restoration.

Look at your personal experience in combating corrosion with the help of inhibitors.

Source: https://oxmetall.ru/metalli/med/kak-protekaet-korroziya-medi

Does brass oxidize? — Metals, equipment, instructions

Anyone who searches for and sells non-ferrous metal sometimes has doubts about the type of scrap and, accordingly, its true value upon delivery.

Copper is a non-ferrous metal, and brass is an alloy that is typically 70% copper, so it often resembles it.

A mistake can be quite costly. For copper at collection points they give 285-300 rubles, for brass - about 150 . There are many ways to find out what kind of metal we see - copper or brass, and we will tell you how to distinguish them from each other in this article.

What is copper and brass

Copper is a non-ferrous metal. Its color is reddish-pink, it is pliable when working, soft and malleable. It has high thermal and electrical conductivity, so copper is often used to produce:

• parts of electrical appliances;
• cables;
• radiators.

Copper is not hardened because it becomes hard even after cold forging. It tends to become covered with patina - a green coating that occurs when the ambient humidity is high.

https://www.youtube.com/watch?v=s2-0hGlxXgw

To increase strength, improve a number of other indicators and reduce the cost of the material, impurities are added and an alloy is obtained.

One such alloy is brass .

In the classic version it contains a third of zinc.

Brass is golden yellow, stronger and harder. It does not oxidize so intensively , and is not so plastic.

Sometimes, depending on the purpose of the alloy, they add:

• tin;
• silicon;
• lead;
• manganese.

Similarities and differences

Brass alloy consists mostly of copper, so it is natural that they are similar not only visually, but also in some properties. The more copper in the alloy, the more similar their colors will be. This is where the exact coincidences end.

Visually, less than 80% copper are easily distinguished . They are slightly similar to gold, as they have a pronounced yellow tint. The more zinc, the lighter the shade.

Because of this, brass is even used to counterfeit or imitate gold . Copper has a main shade of reddish, which often has a pink tint.

With a strong decrease in temperature, brass does not lose its relatively limited ductility and does not become brittle . Conducts electricity and heat worse.

They differ in such a way as hardness .

Copper is softer and more ductile , while brass, on the contrary, is hard and it is difficult to give it any shape without annealing.

The shavings are also different: for brass they are needle- shaped , for copper they are twisted into a spiral .

Let's look at the properties that brass and copper have and whether they have any differences:

Copper	Brass
Plastic, soft	Solid
Reddish-brown-pink tint	Golden tone
Lower sound on impact	Alt
Heavy	Easier
The shavings are twisted into a spiral	Needle shavings

Most often you can distinguish by:

• mind;
• weight;
• degree of hardness

without the use of any tools or equipment.

But there are situations when, for accuracy, it is necessary to use :

• reagents,
• tools,
• devices.

Before assessing the scrap that you are going to take to the collection point, you need to clean it of dirt, otherwise you won’t be able to accurately determine it by eye.

Both metals, although to varying degrees, can develop a patina .

Therefore, do not forget to clean the scrap well.

If an object has been in the open air or in water for a long time, the patina layer is difficult to remove.

Sometimes it will be justified to purchase a special cleaning product .

It is advisable to inspect the scrap under a powerful white light.

This implies that one can view either under the sun on a fine day or under a bright fluorescent lamp . Incandescent lamp is not suitable.

Pure copper will have a reddish-brown tint, sometimes with a pink tint. Keep in mind that brass can be red or orange. This type is commonly used for decorations and water pipes.

If the material has an orange, yellow or golden tint, you can be almost sure that it is brass.

Source: https://spb-metalloobrabotka.com/okislyaetsya-li-latun/

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WATCH THE VIDEO ON THE TOPIC: Polishing brass in St. Petersburg. Protection of brass from oxidation. all-audio.pro

Varnish for brass to prevent it from darkening

Skip to content. You have JavaScript disabled. Some functions may not work. Please enable JavaScript to access all features. Posted September 13 - Anyone know how to weatherproof it? A solution of celluloid in acetone and other solvents. Used to protect printed circuit boards. Not sure it will withstand weathering. Better than any regular waterproof varnish, starting with nitro.

You just need to properly degrease the surface and apply several layers so that it does not peel off and there are no cracks in the future.

Otherwise, everything will become covered with spots and mesh. Or maybe it can be laminated into film? Posted September 14 - HTML mode enabled. The visual editor is not available while HTML is enabled. You may lose some formatting when you turn off HTML mode and return to visual.

System for IP communities. Protection of brass Author Danev, September 13 Posted September 13 — Dear colleagues, Please share your experience. The editorial team had the conceit of making the “KYA” façade sign out of polished brass. Possibly tombaka.

So in some places it gradually darkens from the splashes of water, and our women do not like this. Or to nothing? Sent on September 13 - it is gradually darkening in places due to splashes of water.

There is an ancient method that has been tested for centuries. A watchman is appointed, who every morning walks over the brass with a piece of felt boots. It works radically!

Posted September 13 - Exactly. Asidol, GOI paste and a piece of an overcoat - “our” method! Don’t you now have an anchor on the pedestal in front of the entrance? Otherwise you need to sharpen it. Also regularly. Sent on September 13 - Give free rein to you, my darlings - we'll send the entire editorial staff to the pit. Apparently, Frum will have to do it like an old mechanic. Sent on September 13 - What about acrylic auto varnish?

Posted September 13 - Old anglers use passivation. For a sign, I don’t know, it’s a bit large. The recipe is this: Clean, polish, degrease. For 1 - 2 seconds, lower 1 part nitric acid and 1 part sulfuric acid into the solution. Immediately transfer chrompic into a saturated solution of potassium dichromate.

Keep for 10 - 15 minutes. Rinse and dry. The film is resistant and not afraid of moisture. Holds even in sea water. Well, or felt boots Posted on September 13 - Tsapon-lak. All varnishes on polished brass are highly visible. The appearance of the product is greatly inferior. In addition, they are short-lived. They become cloudy from ultraviolet radiation. They crack due to temperature changes. By the way, a solution of celluloid in acetone with a plasticizer is called dope or enamel. Tsapon is more complex in composition. Overall this is a quality varnish.

Posted September 14 - You're right. The composition written on the bottle with zapon-varnish is organic solvents, acrylic copolymer. Designed for protective and decorative coatings of products made of ferrous and non-ferrous metals. For external and internal works. Nothing is said about UV resistance. All that remains is the felt boot. Number of users reading this topic: 0 0 users, 0 guests, 0 hidden users.

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Antiquax Copper and Brass Polish

Source: https://all-audio.pro/c23/obsuzhdeniya/zashita-latuni-ot-potemneniya.php

How to protect brass from oxidation

Brass is a beautiful metal that attracts attention, but only if it is properly cared for. If you like brass products, it is important to care for them properly. Cleaning brass involves certain rules, if you break them you can say goodbye to your favorite item.

Brass Cleaning Options

Quite often, cleaning brass at home involves creating an acidic environment, because it is the oxides that create unpleasant darkening on the surface. The most popular remedy in this case is oxalic acid, although some believe that any product with a chemical composition that contains acid is available for use.

If you find a detergent containing oxalic acid in your bins, then cleaning the brass item will be easy.

It is enough to lubricate the product with a thick layer and leave for a short period of time. Do not be alarmed that a dark coating will appear during the washing process. To remove it, a brush and running water are enough.

After the product has been washed, cover it with a layer of soda, leaving it for a while, then rinse again under running water. Rub the item with a soft cloth until a characteristic shine appears.

If the pollution is “ingrained”, then it is better to prepare your own oxalic acid solution for work. For ten liters of water, 200 grams of acid are used. The contaminated product is placed in the acid solution. Do not forget about the possible darkening, which you should not be afraid of. Thanks to such a concentrated mixture, you can count on deep cleaning of the metal even from old stains. After the “bath”, send the product for washing, and then rub it properly.

Another chemical liquid ideal for working with brass is acetone. He is able to return it to its original appearance, and working with it is not difficult. It is enough to moisten a cotton swab in acetone and wipe the product until all stains are removed. This method of working is also relevant for copper products.

Folk recipes

Not everyone likes the idea of ​​cleaning products with chemicals, so you have to turn to folk recipes.

Toothpaste

When using toothpaste, first wash the product with soapy water, which will slightly soften old stains. Next, toothpaste is applied to problem areas, which are subsequently scrubbed off. You can use either a regular napkin or a toothbrush, which will allow you to work in hard-to-reach places.

Vinegar

The vinegar mixture will require flour and water. For a glass of any flour, use a glass of water and a glass of table vinegar (9 percent solution). The resulting mixture is rubbed tightly onto the product, after which the mixture must be given time to dry.

Usually this time period is enough for a stain of even high density to be dissolved with vinegar; the flour, in turn, will act as an absorbent agent. It will be enough to walk over the surface with a soft cloth.

If not all stains are removed the first time, repeat the procedure.

Lemon juice with salt

To polish using citrus juice and salt, you will need the juice of half a lemon, to which table salt is added little by little. The amount may vary, so it is important for you to bring the mixture to a paste. The resulting product is applied to the object, and the treatment is carried out with gentle movements in a circle. The remaining product is washed off with water, after which the product is dried with a dry soft cloth.

Soap solution

Soaking in a soap solution can be considered not only as an independent method of work, but also as a preparatory step, which is recommended for any of the above methods. If the stains are fresh, then one soap solution will be enough.

To work, warm water is poured into a basin, and shavings of laundry soap and any dishwashing detergent are dissolved in it. After preliminary foaming, the products are laid for several minutes until the liquid cools down.

After this, the water is drained, and the objects are treated with a soft bristle brush under running water.

Table vinegar

If the brass is covered with individual stains, then hot table vinegar will do the job. The pure product must be heated to a tolerable state. Next, soak a cotton pad in hot vinegar and use it to wipe off individual stains on the surface. If you choose this method, you will need a well-ventilated area to work, as the smell will be quite strong.

How to Protect Brass

In order not to think about emergency methods of cleaning brass items, it is enough to prevent the formation of stains. To do this, wipe the products with a clean cloth, onto which a small amount of olive oil is first applied. It is important to emphasize the word “small”. A thick layer of oil can ruin the polish, which can cause imprints.

To work, just lightly dip a clean, soft cloth in olive oil and transfer it to the surface of the product. Using another clean rag, spread the oil over the surface, which will act as a protective layer. This simple solution will prevent oxidation or minimize it.

Polishing

Polishing brass should be done after each cleaning of the product. You can use special polishes, rubbing them into the surface and then polishing with a soft cloth to the desired shine. Varnishing will also help. This procedure is important to maintain shine and provide reliable protection. It is important to apply the varnish layer evenly. To do this, you can choose a brush or cotton pads. After the varnishing process, it is mandatory to wipe the brass with any cloth.

Source: https://respect-kovka.com/kak-zaschitit-latun-ot-okisleniya/

About the oxidation of brass

Source: https://rus.roomsdecorating.com/about-brass-oxidation_24429

How to clean brass from oxides - Metalworker's Guide

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

Cleaning brass at home

Cleaning brass at home is almost as easy as cleaning copper or bronze, but there are exceptions to this alloy.

In the step-by-step instructions with photos below, using a brass figurine as an example, we will explain how to properly clean the alloy yourself and what preliminary measures should be taken to avoid damaging the surface of the product.

1. First of all, it is necessary to determine the material from which the figurine is made. This is especially true if you do not remember whether it is brass or another metal. Externally, brass resembles gold, the alloy shines and has a not too rich yellow color. If you apply even the smallest magnet to the surface of the figurine, it will not stick. If the product is made of brass, then you should also understand that you can only clean and restore a figurine made of brass with a protective varnish layer. In another case, it is best not to waste time and effort, but to immediately take the product to a specialist.
2. Having decided on the alloy, you can now proceed directly to cleaning. We fill a basin with warm water and add dishwashing detergent to the liquid or rub a small piece of soap. We wipe the surface of the brass product with a flannel cloth, paying special attention to darkening.
3. We carefully wipe the brass figurine dry and proceed to the next stage of restoring the alloy. To do this, we cover the workspace with old newspapers. Armed with a brush, carefully remove the old varnish coating using a special liquid.
4. Once the protective varnish layer has been removed, the brass must be thoroughly polished. For this purpose it is also best to use a specially designed product.
5. We put on cotton gloves so as not to stain the polished brass, and at this stage we coat the product with a new layer of varnish to protect the alloy. The layer should be thin and uniform. Be sure to wait until the product is completely dry.
6. At the final stage, rub the surface of the brass, cleaned to a shine, with a microfiber cloth.

Such simple steps will allow you to restore a brass product if it is not too damaged. Incorrect or untimely care will result in the surface of a brass product, for example, a samovar, becoming covered with unpleasant oxide. In this case, you will have to resort to more serious cleaning of the alloy.

Household chemicals

Household chemicals

On sale you can find household chemicals that are intended exclusively for cleaning brass products. The most common means of cleaning this alloy include:

• household chemicals that contain oxalic acid: just apply the purchased product to the degreased surface of the brass product, and then wait until the acid causes the alloy to become covered with a dark foam (it is easy to wash off the blackened layer under running water);
• Acetone can help remove oxide from the surface of brass; to do this, simply rub a swab dipped in liquid onto the contaminated surface of the brass product;
• toothpaste or powder will also work well to remove serious stains, although these substances are abrasives, they are quite safe to use on brass;
• sandpaper is the most extreme option; if the entire brass product is covered with a thick layer of plaque and oxide, you should act very carefully so as not to damage the alloy that is not affected by corrosion.

Remember! When working with oxalic acid and other aggressive household chemicals, be sure to follow safety precautions by wearing gloves and a respirator. Ventilate the area where you cleaned the brass for several hours.

You can learn how to restore brass at home using a creamy metal surface cleaner by watching the video below.

Folk remedies

Folk remedies

There are a lot of folk remedies for cleaning brass; for convenience, we have collected them in the table below.

Means	Mode of application
Lemon juice	Lemon juice effectively and safely cleans the surface of a brass product from oxide, and also restores the shine of the metal. For greater efficiency, you need to squeeze lemon juice into a small bowl, and then pour table salt into the liquid until the mixture has the consistency of sour cream. We use the prepared product and a soft sponge to clean brass. We process the surface in a circular motion until the layer of dirt begins to collapse. Afterwards, you only need to rinse the cutlery or any other brass items under running water.
Buttermilk	Few people know, but you can clean brass well from darkening using regular buttermilk. Pour about a liter of liquid into a basin, add two tablespoons of fine table salt, using a soft sponge, clean the brass and return the shine to the alloy. After the procedure, the product will need to be rinsed in warm water and wiped dry with a clean towel.
Wheat flour	To clean brass from oxide and darkening at home, it is enough to mix clean water and table vinegar in equal proportions. Wheat flour must be added to the resulting solution to form a paste-like mass. Carefully coat the entire surface of the brass product with the prepared dough, and then wait until the mixture is completely dry. The acid will react with the contamination, and the dough will absorb all the secretions. Afterwards, it will be enough to thoroughly rinse the brass under running water and wipe the surface dry with a towel.
Table vinegar	In case of serious contamination, you can try using the following detergent. Choose a container that you don’t mind spoiling. Pour vinegar into the selected pan and bring the liquid to a boil. Immerse the brass product in boiling vinegar or wipe the oxidized surface with the solution. If the metal has recently been corroded, this product will be very effective.
Baking soda and laundry soap	Last in the table, but not the most effective, is a cleaning product made from baking soda and laundry soap. We'll actually be using the boiling method, which is ideal for copper. Since brass is an alloy of copper, the method will also be effective in this case. We fill a large saucepan with water, rub half of the laundry soap into it and add a few tablespoons of baking soda. Bring the liquid to a boil. We lower the brass into the boiling solution for a while until the contamination is cleared. After this, be sure to replace the varnish coating.

You can also use ketchup, yogurt or white vinegar to clean brass at home. Such products are not very effective, but they will help you quickly deal with minor stains. When cleaning, do not use too much physical force to scrub away dirt. In this way, you can wipe off not only a layer of dirt, but also a layer of original paint on a brass product.

Preventative care

Preventative care

To avoid having to wonder how to clean brass from stains and restore the shine of the product, it is enough to perform preventative cleaning of the alloy. The following tips will help you keep your brass in tip-top condition at all times:

• Dry clean brass products regularly, do not allow dust to accumulate in places that are inaccessible for thorough cleaning;
• brass and other alloys do not withstand ultraviolet radiation very well, so samovars and kitchen utensils made from this alloy are best stored in chests of drawers and drawers;
• do not allow increased humidity in the room where brass is stored;
• store jewelry made of copper, brass and bronze separately from each other in special boxes or cases, which are lined with soft fabric on the inside;
• polish brass products with special products: this way the metal will always remain light and shiny.

Caring for products made from various alloys is quite simple, but many people neglect even regular dry cleaning, so they have to look for ways to clean oxide and dark spots.

Even if you don't know it, there may be quite a few brass items in your apartment.

These include candlesticks, metal chandelier inserts, picture frames, antique samovars, teapots and pots, cutlery, vases and pots, taps and decorative figurines. It is very important to take care of brass products so that they are always clean.

  Brass melting temperature

The presented material contains all the necessary information on how and with what you can clean and restore brass at home quickly, simply and effectively. After cleaning, all that remains is to maintain cleanliness and properly store brass products.

Similar materials

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Storing blanketsDry cleaning clothesHow to wash pomegranate?

Source: https://ssk2121.com/chem-chistit-latun-ot-okislov/

How to clean metal from oxidation

How to clean metal from oxidation

How to clean copper? The relevance of this issue is explained by the fact that products made from this metal have been used by humanity for many centuries. For a long time, the value of this metal was so high that it was equal to gold.

The development of technology has led to the fact that it was possible to significantly reduce the cost of copper production. This made it possible to make not only jewelry from this metal, but also dishes and interior items.

The high popularity of this metal and alloys based on it is explained not only by its decorative effect, but also by its unique characteristics - high ductility, thermal conductivity, corrosion resistance, etc.

No one wants to use oxidized copper cookware.

Why copper products need to be cleaned regularly

Why copper products need to be cleaned regularly

Regular cleaning of copper utensils and other items made from this metal is necessary because during use they quickly darken or become covered with a green coating - an oxide film.

Those products made of copper and its alloys that are often heated during operation or used outdoors are the most actively oxidized.

Dishes made of copper, with active use, quickly lose their original shine and become dull; their surface may become black.

Copper jewelry behaves somewhat differently: it may first fade and lose its shine, and then return to its original appearance. Some people believe that the appearance of copper jewelry (for example, a bracelet) is influenced by the well-being of the person who constantly wears it.

However, this is most likely due to the fact that in the external environment with which such a product is constantly in contact, humidity, pressure and temperature are constantly changing.

Meanwhile, many adherents of alternative medicine recommend wearing copper bracelets for people experiencing problems with the cardiovascular system.

A rare samovar preserved from our great-grandfathers evokes something homely and dear

Copper utensils, which our distant ancestors began to use, are still held in high esteem by many housewives today.

This popularity is explained by the fact that in copper cookware, which is characterized by high thermal conductivity, all cooked products are heated evenly and in full, and such heating occurs in a short period of time.

Meanwhile, with constant use, dishes made of this metal quickly lose their visual appeal: they become covered with a coating of oxide, become dull, darken and lose their original shine.

If you do not clean it, it will release toxic substances, and therefore cannot be used for cooking.

If it is not possible to clean such dishes using all known means, it is better not to use them for their intended purpose, so as not to harm your health.

You should also keep in mind that dishes with black or green oxide spots on the surface look unpresentable, so they will not decorate your kitchen.

Effective cleaning methods

Effective cleaning methods

There are many proven methods that allow you to clean copper products even at home. Let's get acquainted with the most effective of them.

Method No. 1

One of the most accessible home remedies for cleaning objects made of copper is regular tomato ketchup. In order to clean copper with this product, it is simply applied to the surface to be treated and left on it for 1-2 minutes. After this exposure, the ketchup is washed off with a stream of warm water. As a result of this procedure, the copper product will return to its original shine and brightness of color.

Ketchup as a cleaning agent

Method No. 2

You can clean copper items, if they are not very dirty, at home using regular dishwashing gel. To do this, use a soft sponge on which detergent is applied. Wash it off under running warm water.

For slightly tarnished copper items, try washing them as normal dishes.

Method No. 3

This cleaning method is used if it is necessary to clean a large copper product that cannot be placed in any container. The surface of such an object is wiped with half a lemon. To enhance the effect of lemon juice on copper, you can clean it with a brush with bristles that have sufficient elasticity.

Method No. 4

A product called “vinegar paste” helps give copper its former shine. It is prepared as follows. In a special container, mix wheat flour and vinegar in equal proportions, bringing the resulting mass to a homogeneous state. Then the dough is applied to a copper object and left until completely dry. The crust formed after the mixture has dried is carefully removed, and the copper surface is polished to a shine with a piece of soft cloth.

Method No. 5

Vinegar, salt and heat together will help clean tough stains.

There is a radical and effective method of cleaning products made of copper, which is used if their surface is heavily soiled and it was not possible to clean them with other means.

• Vinegar is poured into a specially prepared stainless steel container, which is mixed with a small amount of table salt.
• Place the item to be cleaned into the resulting solution and place the container on the fire.
• After the cleaning solution has reached a boil, turn off the heat under the container and leave it on the stove until it cools completely.
• After the solution has cooled, the product to be cleaned is removed, washed under running warm water and its surface wiped dry.

If you clean copper using any of the above methods, strictly adhere to safety rules, carry out all work wearing protective gloves, and be sure to wear a respirator when working with acetic acid.

Cleaning Copper Coins

Cleaning Copper Coins

Coins made of copper are no longer issued in our time, and many such products in the hands of the population are of antique value. That is why the question of how to effectively and at the same time carefully clean such coins is quite relevant.

You can restore the former attractiveness of copper coins using several methods. The choice of each of them depends on the nature and degree of contamination. So, depending on what color the plaque has formed on the surface of the old copper coin, you can clean it using one of the methods listed below.

• If there is a yellowish coating on the surface of the coin (this indicates that it has been in contact with a lead product), then it should be cleaned with a 9% vinegar solution.
• Clearly green plaque is cleaned with a 10% citric acid solution.
• Coins made from copper may also have a reddish coating. Such a coin is cleaned by dipping it in a 5% ammonia solution or ammonium carbonate.

Calculate the use of chemicals depending on the degree of contamination

Old coins made from copper may have a layer of patina, which gives them a more noble and aged appearance. If there is no such plaque, you can create it yourself, even at home. To do this, use a solution consisting of a liter of distilled water, 50 grams of copper sulfate and 5 grams of potassium permanganate.

The resulting solution is heated over low heat, without bringing it to a boil, and then coins are placed in it, which must be covered with a layer of patina. They are periodically turned over, and when the color of their surface acquires the desired shade, they are removed.

Source: https://steelfactoryrus.com/kak-ochistit-metall-ot-okisleniya/

How to protect copper from oxidation? — Machine tools, welding, metalworking

How to protect copper from oxidation? — Machine tools, welding, metalworking

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

How copper corrosion occurs in water, alkali, and acid. Protection measures

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

Corrosion of copper in the soil is mainly caused by the influence of acids contained in the soil. Compared with the effects of water, oxygen in the soil oxidizes metal elements much less. The most dangerous microorganisms in the soil are, or rather, their secretions. They are often capable of releasing hydrogen sulfide, which destroys metal. Thus, copper lying in the soil for a long time can completely decompose.

In humid air the process does not proceed rapidly. It takes a long time. In a dry climate, destructive effects may not be observed at all. This is explained by the fact that in humid air there is a high concentration of carbon dioxide, sulfides, chlorides, which cause corrosion and are destructive to the protective film.

Prolonged exposure to humid air can cause the formation of a patina layer. This is the name given to green deposits on copper. It consists of salt oxides, which are initially dark brown in color, and then the surface begins to turn green.

The peculiarity of patina is that it cannot be dissolved in water and is not affected by high air humidity. It has neutral properties to copper itself, which allows it to protect the surface from the harmful effects of the environment.

In addition, modern methods of creating artificial patina make it possible to use it in objects of art and during restoration.

Look at your personal experience in combating corrosion with the help of inhibitors.

Source: https://oxmetall.ru/metalli/med/kak-protekaet-korroziya-medi

Does brass oxidize? — Metals, equipment, instructions

Anyone who searches for and sells non-ferrous metal sometimes has doubts about the type of scrap and, accordingly, its true value upon delivery.

Copper is a non-ferrous metal, and brass is an alloy that is typically 70% copper, so it often resembles it.

A mistake can be quite costly. For copper at collection points they give 285-300 rubles, for brass - about 150 . There are many ways to find out what kind of metal we see - copper or brass, and we will tell you how to distinguish them from each other in this article.

What is copper and brass

Copper is a non-ferrous metal. Its color is reddish-pink, it is pliable when working, soft and malleable. It has high thermal and electrical conductivity, so copper is often used to produce:

• parts of electrical appliances;
• cables;
• radiators.

Copper is not hardened because it becomes hard even after cold forging. It tends to become covered with patina - a green coating that occurs when the ambient humidity is high.

https://www.youtube.com/watch?v=s2-0hGlxXgw

To increase strength, improve a number of other indicators and reduce the cost of the material, impurities are added and an alloy is obtained.

One such alloy is brass .

In the classic version it contains a third of zinc.

Brass is golden yellow, stronger and harder. It does not oxidize so intensively , and is not so plastic.

Sometimes, depending on the purpose of the alloy, they add:

• tin;
• silicon;
• lead;
• manganese.

Similarities and differences

Brass alloy consists mostly of copper, so it is natural that they are similar not only visually, but also in some properties. The more copper in the alloy, the more similar their colors will be. This is where the exact coincidences end.

Visually, less than 80% copper are easily distinguished . They are slightly similar to gold, as they have a pronounced yellow tint. The more zinc, the lighter the shade.

Because of this, brass is even used to counterfeit or imitate gold . Copper has a main shade of reddish, which often has a pink tint.

With a strong decrease in temperature, brass does not lose its relatively limited ductility and does not become brittle . Conducts electricity and heat worse.

They differ in such a way as hardness .

Copper is softer and more ductile , while brass, on the contrary, is hard and it is difficult to give it any shape without annealing.

The shavings are also different: for brass they are needle- shaped , for copper they are twisted into a spiral .

Let's look at the properties that brass and copper have and whether they have any differences:

Copper	Brass
Plastic, soft	Solid
Reddish-brown-pink tint	Golden tone
Lower sound on impact	Alt
Heavy	Easier
The shavings are twisted into a spiral	Needle shavings

Most often you can distinguish by:

• mind;
• weight;
• degree of hardness

without the use of any tools or equipment.

But there are situations when, for accuracy, it is necessary to use :

• reagents,
• tools,
• devices.

Before assessing the scrap that you are going to take to the collection point, you need to clean it of dirt, otherwise you won’t be able to accurately determine it by eye.

Both metals, although to varying degrees, can develop a patina .

Therefore, do not forget to clean the scrap well.

If an object has been in the open air or in water for a long time, the patina layer is difficult to remove.

Sometimes it will be justified to purchase a special cleaning product .

It is advisable to inspect the scrap under a powerful white light.

This implies that one can view either under the sun on a fine day or under a bright fluorescent lamp . Incandescent lamp is not suitable.

Pure copper will have a reddish-brown tint, sometimes with a pink tint. Keep in mind that brass can be red or orange. This type is commonly used for decorations and water pipes.

If the material has an orange, yellow or golden tint, you can be almost sure that it is brass.

Source: https://spb-metalloobrabotka.com/okislyaetsya-li-latun/

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WATCH THE VIDEO ON THE TOPIC: Polishing brass in St. Petersburg. Protection of brass from oxidation. all-audio.pro

Varnish for brass to prevent it from darkening

Skip to content. You have JavaScript disabled. Some functions may not work. Please enable JavaScript to access all features. Posted September 13 - Anyone know how to weatherproof it? A solution of celluloid in acetone and other solvents. Used to protect printed circuit boards. Not sure it will withstand weathering. Better than any regular waterproof varnish, starting with nitro.

You just need to properly degrease the surface and apply several layers so that it does not peel off and there are no cracks in the future.

Otherwise, everything will become covered with spots and mesh. Or maybe it can be laminated into film? Posted September 14 - HTML mode enabled. The visual editor is not available while HTML is enabled. You may lose some formatting when you turn off HTML mode and return to visual.

System for IP communities. Protection of brass Author Danev, September 13 Posted September 13 — Dear colleagues, Please share your experience. The editorial team had the conceit of making the “KYA” façade sign out of polished brass. Possibly tombaka.

So in some places it gradually darkens from the splashes of water, and our women do not like this. Or to nothing? Sent on September 13 - it is gradually darkening in places due to splashes of water.

There is an ancient method that has been tested for centuries. A watchman is appointed, who every morning walks over the brass with a piece of felt boots. It works radically!

Posted September 13 - Exactly. Asidol, GOI paste and a piece of an overcoat - “our” method! Don’t you now have an anchor on the pedestal in front of the entrance? Otherwise you need to sharpen it. Also regularly. Sent on September 13 - Give free rein to you, my darlings - we'll send the entire editorial staff to the pit. Apparently, Frum will have to do it like an old mechanic. Sent on September 13 - What about acrylic auto varnish?

Posted September 13 - Old anglers use passivation. For a sign, I don’t know, it’s a bit large. The recipe is this: Clean, polish, degrease. For 1 - 2 seconds, lower 1 part nitric acid and 1 part sulfuric acid into the solution. Immediately transfer chrompic into a saturated solution of potassium dichromate.

Keep for 10 - 15 minutes. Rinse and dry. The film is resistant and not afraid of moisture. Holds even in sea water. Well, or felt boots Posted on September 13 - Tsapon-lak. All varnishes on polished brass are highly visible. The appearance of the product is greatly inferior. In addition, they are short-lived. They become cloudy from ultraviolet radiation. They crack due to temperature changes. By the way, a solution of celluloid in acetone with a plasticizer is called dope or enamel. Tsapon is more complex in composition. Overall this is a quality varnish.

Posted September 14 - You're right. The composition written on the bottle with zapon-varnish is organic solvents, acrylic copolymer. Designed for protective and decorative coatings of products made of ferrous and non-ferrous metals. For external and internal works. Nothing is said about UV resistance. All that remains is the felt boot. Number of users reading this topic: 0 0 users, 0 guests, 0 hidden users.

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Antiquax Copper and Brass Polish

Source: https://all-audio.pro/c23/obsuzhdeniya/zashita-latuni-ot-potemneniya.php

How to protect brass from oxidation

Brass is a beautiful metal that attracts attention, but only if it is properly cared for. If you like brass products, it is important to care for them properly. Cleaning brass involves certain rules, if you break them you can say goodbye to your favorite item.

Brass Cleaning Options

Quite often, cleaning brass at home involves creating an acidic environment, because it is the oxides that create unpleasant darkening on the surface. The most popular remedy in this case is oxalic acid, although some believe that any product with a chemical composition that contains acid is available for use.

If you find a detergent containing oxalic acid in your bins, then cleaning the brass item will be easy.

It is enough to lubricate the product with a thick layer and leave for a short period of time. Do not be alarmed that a dark coating will appear during the washing process. To remove it, a brush and running water are enough.

After the product has been washed, cover it with a layer of soda, leaving it for a while, then rinse again under running water. Rub the item with a soft cloth until a characteristic shine appears.

If the pollution is “ingrained”, then it is better to prepare your own oxalic acid solution for work. For ten liters of water, 200 grams of acid are used. The contaminated product is placed in the acid solution. Do not forget about the possible darkening, which you should not be afraid of. Thanks to such a concentrated mixture, you can count on deep cleaning of the metal even from old stains. After the “bath”, send the product for washing, and then rub it properly.

Another chemical liquid ideal for working with brass is acetone. He is able to return it to its original appearance, and working with it is not difficult. It is enough to moisten a cotton swab in acetone and wipe the product until all stains are removed. This method of working is also relevant for copper products.

Folk recipes

Not everyone likes the idea of ​​cleaning products with chemicals, so you have to turn to folk recipes.

Toothpaste

When using toothpaste, first wash the product with soapy water, which will slightly soften old stains. Next, toothpaste is applied to problem areas, which are subsequently scrubbed off. You can use either a regular napkin or a toothbrush, which will allow you to work in hard-to-reach places.

Vinegar

The vinegar mixture will require flour and water. For a glass of any flour, use a glass of water and a glass of table vinegar (9 percent solution). The resulting mixture is rubbed tightly onto the product, after which the mixture must be given time to dry.

Usually this time period is enough for a stain of even high density to be dissolved with vinegar; the flour, in turn, will act as an absorbent agent. It will be enough to walk over the surface with a soft cloth.

If not all stains are removed the first time, repeat the procedure.

Lemon juice with salt

To polish using citrus juice and salt, you will need the juice of half a lemon, to which table salt is added little by little. The amount may vary, so it is important for you to bring the mixture to a paste. The resulting product is applied to the object, and the treatment is carried out with gentle movements in a circle. The remaining product is washed off with water, after which the product is dried with a dry soft cloth.

Soap solution

Soaking in a soap solution can be considered not only as an independent method of work, but also as a preparatory step, which is recommended for any of the above methods. If the stains are fresh, then one soap solution will be enough.

To work, warm water is poured into a basin, and shavings of laundry soap and any dishwashing detergent are dissolved in it. After preliminary foaming, the products are laid for several minutes until the liquid cools down.

After this, the water is drained, and the objects are treated with a soft bristle brush under running water.

Table vinegar

If the brass is covered with individual stains, then hot table vinegar will do the job. The pure product must be heated to a tolerable state. Next, soak a cotton pad in hot vinegar and use it to wipe off individual stains on the surface. If you choose this method, you will need a well-ventilated area to work, as the smell will be quite strong.

How to Protect Brass

In order not to think about emergency methods of cleaning brass items, it is enough to prevent the formation of stains. To do this, wipe the products with a clean cloth, onto which a small amount of olive oil is first applied. It is important to emphasize the word “small”. A thick layer of oil can ruin the polish, which can cause imprints.

To work, just lightly dip a clean, soft cloth in olive oil and transfer it to the surface of the product. Using another clean rag, spread the oil over the surface, which will act as a protective layer. This simple solution will prevent oxidation or minimize it.

Polishing

Polishing brass should be done after each cleaning of the product. You can use special polishes, rubbing them into the surface and then polishing with a soft cloth to the desired shine. Varnishing will also help. This procedure is important to maintain shine and provide reliable protection. It is important to apply the varnish layer evenly. To do this, you can choose a brush or cotton pads. After the varnishing process, it is mandatory to wipe the brass with any cloth.

Source: https://respect-kovka.com/kak-zaschitit-latun-ot-okisleniya/

About the oxidation of brass

Source: https://rus.roomsdecorating.com/about-brass-oxidation_24429

How to clean brass from oxides - Metalworker's Guide

« How to clean brass? “- this is the question asked by housewives who have among their kitchen utensils forks and spoons made of this alloy, and maybe even an antique samovar. Brass looks very bright, attractive and aesthetically pleasing, but only if the alloy is clean and polished. Not everyone knows how to properly care for brass, or how to clean such metal if necessary.

In this article we will look in detail at what means can safely and effectively restore darkened brass, how to clean the alloy from various contaminants, and how to properly care for brass products so that they do not corrode.

Cleaning brass at home

Cleaning brass at home is almost as easy as cleaning copper or bronze, but there are exceptions to this alloy.

In the step-by-step instructions with photos below, using a brass figurine as an example, we will explain how to properly clean the alloy yourself and what preliminary measures should be taken to avoid damaging the surface of the product.

1. First of all, it is necessary to determine the material from which the figurine is made. This is especially true if you do not remember whether it is brass or another metal. Externally, brass resembles gold, the alloy shines and has a not too rich yellow color. If you apply even the smallest magnet to the surface of the figurine, it will not stick. If the product is made of brass, then you should also understand that you can only clean and restore a figurine made of brass with a protective varnish layer. In another case, it is best not to waste time and effort, but to immediately take the product to a specialist.
2. Having decided on the alloy, you can now proceed directly to cleaning. We fill a basin with warm water and add dishwashing detergent to the liquid or rub a small piece of soap. We wipe the surface of the brass product with a flannel cloth, paying special attention to darkening.
3. We carefully wipe the brass figurine dry and proceed to the next stage of restoring the alloy. To do this, we cover the workspace with old newspapers. Armed with a brush, carefully remove the old varnish coating using a special liquid.
4. Once the protective varnish layer has been removed, the brass must be thoroughly polished. For this purpose it is also best to use a specially designed product.
5. We put on cotton gloves so as not to stain the polished brass, and at this stage we coat the product with a new layer of varnish to protect the alloy. The layer should be thin and uniform. Be sure to wait until the product is completely dry.
6. At the final stage, rub the surface of the brass, cleaned to a shine, with a microfiber cloth.

Such simple steps will allow you to restore a brass product if it is not too damaged. Incorrect or untimely care will result in the surface of a brass product, for example, a samovar, becoming covered with unpleasant oxide. In this case, you will have to resort to more serious cleaning of the alloy.

Household chemicals

On sale you can find household chemicals that are intended exclusively for cleaning brass products. The most common means of cleaning this alloy include:

• household chemicals that contain oxalic acid: just apply the purchased product to the degreased surface of the brass product, and then wait until the acid causes the alloy to become covered with a dark foam (it is easy to wash off the blackened layer under running water);
• Acetone can help remove oxide from the surface of brass; to do this, simply rub a swab dipped in liquid onto the contaminated surface of the brass product;
• toothpaste or powder will also work well to remove serious stains, although these substances are abrasives, they are quite safe to use on brass;
• sandpaper is the most extreme option; if the entire brass product is covered with a thick layer of plaque and oxide, you should act very carefully so as not to damage the alloy that is not affected by corrosion.

Remember! When working with oxalic acid and other aggressive household chemicals, be sure to follow safety precautions by wearing gloves and a respirator. Ventilate the area where you cleaned the brass for several hours.

You can learn how to restore brass at home using a creamy metal surface cleaner by watching the video below.

Folk remedies

There are a lot of folk remedies for cleaning brass; for convenience, we have collected them in the table below.

Means	Mode of application
Lemon juice	Lemon juice effectively and safely cleans the surface of a brass product from oxide, and also restores the shine of the metal. For greater efficiency, you need to squeeze lemon juice into a small bowl, and then pour table salt into the liquid until the mixture has the consistency of sour cream. We use the prepared product and a soft sponge to clean brass. We process the surface in a circular motion until the layer of dirt begins to collapse. Afterwards, you only need to rinse the cutlery or any other brass items under running water.
Buttermilk	Few people know, but you can clean brass well from darkening using regular buttermilk. Pour about a liter of liquid into a basin, add two tablespoons of fine table salt, using a soft sponge, clean the brass and return the shine to the alloy. After the procedure, the product will need to be rinsed in warm water and wiped dry with a clean towel.
Wheat flour	To clean brass from oxide and darkening at home, it is enough to mix clean water and table vinegar in equal proportions. Wheat flour must be added to the resulting solution to form a paste-like mass. Carefully coat the entire surface of the brass product with the prepared dough, and then wait until the mixture is completely dry. The acid will react with the contamination, and the dough will absorb all the secretions. Afterwards, it will be enough to thoroughly rinse the brass under running water and wipe the surface dry with a towel.
Table vinegar	In case of serious contamination, you can try using the following detergent. Choose a container that you don’t mind spoiling. Pour vinegar into the selected pan and bring the liquid to a boil. Immerse the brass product in boiling vinegar or wipe the oxidized surface with the solution. If the metal has recently been corroded, this product will be very effective.
Baking soda and laundry soap	Last in the table, but not the most effective, is a cleaning product made from baking soda and laundry soap. We'll actually be using the boiling method, which is ideal for copper. Since brass is an alloy of copper, the method will also be effective in this case. We fill a large saucepan with water, rub half of the laundry soap into it and add a few tablespoons of baking soda. Bring the liquid to a boil. We lower the brass into the boiling solution for a while until the contamination is cleared. After this, be sure to replace the varnish coating.

You can also use ketchup, yogurt or white vinegar to clean brass at home. Such products are not very effective, but they will help you quickly deal with minor stains. When cleaning, do not use too much physical force to scrub away dirt. In this way, you can wipe off not only a layer of dirt, but also a layer of original paint on a brass product.

Preventative care

To avoid having to wonder how to clean brass from stains and restore the shine of the product, it is enough to perform preventative cleaning of the alloy. The following tips will help you keep your brass in tip-top condition at all times:

• Dry clean brass products regularly, do not allow dust to accumulate in places that are inaccessible for thorough cleaning;
• brass and other alloys do not withstand ultraviolet radiation very well, so samovars and kitchen utensils made from this alloy are best stored in chests of drawers and drawers;
• do not allow increased humidity in the room where brass is stored;
• store jewelry made of copper, brass and bronze separately from each other in special boxes or cases, which are lined with soft fabric on the inside;
• polish brass products with special products: this way the metal will always remain light and shiny.

Caring for products made from various alloys is quite simple, but many people neglect even regular dry cleaning, so they have to look for ways to clean oxide and dark spots.

Even if you don't know it, there may be quite a few brass items in your apartment.

These include candlesticks, metal chandelier inserts, picture frames, antique samovars, teapots and pots, cutlery, vases and pots, taps and decorative figurines. It is very important to take care of brass products so that they are always clean.

  Brass melting temperature

The presented material contains all the necessary information on how and with what you can clean and restore brass at home quickly, simply and effectively. After cleaning, all that remains is to maintain cleanliness and properly store brass products.

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Source: https://ssk2121.com/chem-chistit-latun-ot-okislov/

How to clean metal from oxidation

How to clean copper? The relevance of this issue is explained by the fact that products made from this metal have been used by humanity for many centuries. For a long time, the value of this metal was so high that it was equal to gold.

The development of technology has led to the fact that it was possible to significantly reduce the cost of copper production. This made it possible to make not only jewelry from this metal, but also dishes and interior items.

The high popularity of this metal and alloys based on it is explained not only by its decorative effect, but also by its unique characteristics - high ductility, thermal conductivity, corrosion resistance, etc.

No one wants to use oxidized copper cookware.

Why copper products need to be cleaned regularly

Regular cleaning of copper utensils and other items made from this metal is necessary because during use they quickly darken or become covered with a green coating - an oxide film.

Those products made of copper and its alloys that are often heated during operation or used outdoors are the most actively oxidized.

Dishes made of copper, with active use, quickly lose their original shine and become dull; their surface may become black.

Copper jewelry behaves somewhat differently: it may first fade and lose its shine, and then return to its original appearance. Some people believe that the appearance of copper jewelry (for example, a bracelet) is influenced by the well-being of the person who constantly wears it.

However, this is most likely due to the fact that in the external environment with which such a product is constantly in contact, humidity, pressure and temperature are constantly changing.

Meanwhile, many adherents of alternative medicine recommend wearing copper bracelets for people experiencing problems with the cardiovascular system.

A rare samovar preserved from our great-grandfathers evokes something homely and dear

Copper utensils, which our distant ancestors began to use, are still held in high esteem by many housewives today.

This popularity is explained by the fact that in copper cookware, which is characterized by high thermal conductivity, all cooked products are heated evenly and in full, and such heating occurs in a short period of time.

Meanwhile, with constant use, dishes made of this metal quickly lose their visual appeal: they become covered with a coating of oxide, become dull, darken and lose their original shine.

If you do not clean it, it will release toxic substances, and therefore cannot be used for cooking.

If it is not possible to clean such dishes using all known means, it is better not to use them for their intended purpose, so as not to harm your health.

You should also keep in mind that dishes with black or green oxide spots on the surface look unpresentable, so they will not decorate your kitchen.

Effective cleaning methods

There are many proven methods that allow you to clean copper products even at home. Let's get acquainted with the most effective of them.

Method No. 1

One of the most accessible home remedies for cleaning objects made of copper is regular tomato ketchup. In order to clean copper with this product, it is simply applied to the surface to be treated and left on it for 1-2 minutes. After this exposure, the ketchup is washed off with a stream of warm water. As a result of this procedure, the copper product will return to its original shine and brightness of color.

Ketchup as a cleaning agent

Method No. 2

You can clean copper items, if they are not very dirty, at home using regular dishwashing gel. To do this, use a soft sponge on which detergent is applied. Wash it off under running warm water.

For slightly tarnished copper items, try washing them as normal dishes.

Method No. 3

This cleaning method is used if it is necessary to clean a large copper product that cannot be placed in any container. The surface of such an object is wiped with half a lemon. To enhance the effect of lemon juice on copper, you can clean it with a brush with bristles that have sufficient elasticity.

Method No. 4

A product called “vinegar paste” helps give copper its former shine. It is prepared as follows. In a special container, mix wheat flour and vinegar in equal proportions, bringing the resulting mass to a homogeneous state. Then the dough is applied to a copper object and left until completely dry. The crust formed after the mixture has dried is carefully removed, and the copper surface is polished to a shine with a piece of soft cloth.

Method No. 5

Vinegar, salt and heat together will help clean tough stains.

There is a radical and effective method of cleaning products made of copper, which is used if their surface is heavily soiled and it was not possible to clean them with other means.

• Vinegar is poured into a specially prepared stainless steel container, which is mixed with a small amount of table salt.
• Place the item to be cleaned into the resulting solution and place the container on the fire.
• After the cleaning solution has reached a boil, turn off the heat under the container and leave it on the stove until it cools completely.
• After the solution has cooled, the product to be cleaned is removed, washed under running warm water and its surface wiped dry.

If you clean copper using any of the above methods, strictly adhere to safety rules, carry out all work wearing protective gloves, and be sure to wear a respirator when working with acetic acid.

Cleaning Copper Coins

Coins made of copper are no longer issued in our time, and many such products in the hands of the population are of antique value. That is why the question of how to effectively and at the same time carefully clean such coins is quite relevant.

You can restore the former attractiveness of copper coins using several methods. The choice of each of them depends on the nature and degree of contamination. So, depending on what color the plaque has formed on the surface of the old copper coin, you can clean it using one of the methods listed below.

• If there is a yellowish coating on the surface of the coin (this indicates that it has been in contact with a lead product), then it should be cleaned with a 9% vinegar solution.
• Clearly green plaque is cleaned with a 10% citric acid solution.
• Coins made from copper may also have a reddish coating. Such a coin is cleaned by dipping it in a 5% ammonia solution or ammonium carbonate.

Calculate the use of chemicals depending on the degree of contamination

Old coins made from copper may have a layer of patina, which gives them a more noble and aged appearance. If there is no such plaque, you can create it yourself, even at home. To do this, use a solution consisting of a liter of distilled water, 50 grams of copper sulfate and 5 grams of potassium permanganate.

The resulting solution is heated over low heat, without bringing it to a boil, and then coins are placed in it, which must be covered with a layer of patina. They are periodically turned over, and when the color of their surface acquires the desired shade, they are removed.

Source: https://steelfactoryrus.com/kak-ochistit-metall-ot-okisleniya/

How to protect copper from oxidation? — Machine tools, welding, metalworking

Corrosion of copper is not as well known as the corrosive effects of iron. However, the mechanisms of influence on the metal structure are similar. This is spontaneous destruction when exposed to various types of aggressive environments. It is impossible to unequivocally compare the concept of rust with copper corrosion.

Corrosion of any metal is associated with thermodynamic instability under the influence of active elements that are in the air. The rate of copper corrosion will directly depend on temperature fluctuations. If you increase it by 100 degrees, the pace increases 2-3 times.

Next, we will consider how corrosion of copper alloys occurs and how to protect them from oxidation in various deployment environments.

Corrosive properties

Due to the lack of chemical activity in copper, upon contact with water or humid air, its corrosion practically does not occur. When exposed to dry air, the metal can form a small oxide film up to 50 nm thick. If the product is tinned, then almost no film is formed.

A high-quality tin coating can reliably protect against moisture and temperature changes. Moreover, the service life of such an item can be up to 100 years without loss of original properties. The color will not change over time. The use of tinned surfaces has long shown its best performance.

An example would be the domes of many temples.

Due to the high threshold of corrosion resistance, copper is actively used in many chemical and electrochemical industries. For example, the process of copper plating helps solve many processing problems. In one of the previous articles, we looked at the procedure at home, we recommend that you read it.

Water influence

Corrosion of copper in water and the speed of the process will depend on the presence of an oxide film and the volume of oxygen dissolved in it. As a rule, an impact or point process occurs. In this case, the speed will be faster, the greater the amount of oxygen contained in the water. A liquid containing chlorine ions and a low pH level will also have a negative effect.

In general, the surface’s resistance to corrosive influences is quite high, which is facilitated by the presence of an oxide film, which does not allow the destructive element to penetrate into the metal structure. An oxide layer will form when the metal remains in water for more than 2 months. Oxide coating can be of two types:

• · Carbonate – green in color. It is considered to be the most durable.
• · Sulfate – dark in color. It has a loose structure and less strength.

The metal is often used in the production of various pipelines. However, if the liquid flowing through them comes into contact with aluminum, zinc, or iron, then it significantly accelerates their corrosion. To prevent this and protect copper from corrosion, tin plating is again carried out.

Effect of acid and alkali

Corrosion of copper in acidic environments is less detected. The effect of nitric and sulfuric acid will be the strongest. If you place it in a concentrate of these acids, it can completely dissolve. These features are taken into account when choosing alloys for elements and pipelines in the oil and gas industry.

In an alkaline environment, the effect is not observed at all, since alkali allows copper to be reduced from a 2-valent to a 1-valent state. It is worth remembering that it itself is an alkali metal.

Protection against oxidation and corrosion under the influence of acids is carried out by inhibitors - substances that slow down the chemical reaction. The following types can be distinguished:

• · Shielding – form protective lashes and exclude the possibility of contact with acids.
• · Oxidative – the formation of an oxide occurs, which reacts with acids, thereby preventing their penetration into the metal structure.
• · Cathode – designed to increase the overvoltage of the cathodes of the solution, due to which chemical reactions reduce their intensity.

As a rule, corrosion of copper in acidic environments is prevented by shielding type inhibitors. The most common is benzotriazole, which, together with copper salt formations, forms a protective shell, slowing down the rate of corrosion or almost completely stopping it.

Exposure to soil and moist air

Corrosion of copper in the soil is mainly caused by the influence of acids contained in the soil. Compared with the effects of water, oxygen in the soil oxidizes metal elements much less. The most dangerous microorganisms in the soil are, or rather, their secretions. They are often capable of releasing hydrogen sulfide, which destroys metal. Thus, copper lying in the soil for a long time can completely decompose.

In humid air the process does not proceed rapidly. It takes a long time. In a dry climate, destructive effects may not be observed at all. This is explained by the fact that in humid air there is a high concentration of carbon dioxide, sulfides, chlorides, which cause corrosion and are destructive to the protective film.

Prolonged exposure to humid air can cause the formation of a patina layer. This is the name given to green deposits on copper. It consists of salt oxides, which are initially dark brown in color, and then the surface begins to turn green.

The peculiarity of patina is that it cannot be dissolved in water and is not affected by high air humidity. It has neutral properties to copper itself, which allows it to protect the surface from the harmful effects of the environment.

In addition, modern methods of creating artificial patina make it possible to use it in objects of art and during restoration.

Look at your personal experience in combating corrosion with the help of inhibitors.

Source: https://stanki-info.com/kak-zaschitit-med-ot-okisleniya/