What are alloy components

How gold alloy composition affects the hue of gold

In the jewelry industry, gold is considered an indispensable material. Products made from this metal are distinguished by a pleasant shine, noble texture and aesthetic appeal. The Latin name for gold, Aurum, literally means “yellow.” Natural metal really has this color.

It also has a high level of ductility and malleability. From one gram of gold you can draw a wire with a length of approximately 3.5 km. If necessary, the metal is rolled into sheets whose thickness is no more than 0.0001 mm.

The distinctive characteristics of this noble material are sufficient density, good thermal conductivity and a high melting point.

Jewelry alloy as an opportunity to obtain different shades of gold

In the jewelry industry, noble metals in their pure form are very rarely used. Products made from alloys are characterized by a long service life and increased strength. The composition of the working material is regulated by GOST standards. The proportion of gold in products is determined by a special sample. The color shade of the decoration is determined by the presence of additional components in the alloy - ligature:

1. Silver.
2. Copper.
3. Platinum.
4. Palladia.

The traditional colors of gold jewelry are yellow, red and white. Modern technologies make it possible to produce jewelry in a wider range of shades.

How to obtain color shades of material for making jewelry

The red color of gold is a sign of the presence of copper in the alloy. The color saturation depends on the amount of metal. This type of material fits perfectly with any decorative inserts. He looks self-sufficient and noble. With equal proportions of gold, copper and silver, a lemon tint is obtained.

Most often, this material is used to make wedding rings or jewelry with multi-colored stone inserts. Products made of white gold are very popular among connoisseurs of beautiful accessories. Palladium or platinum is added to the material of such products. Such components contribute not only to the aesthetic appearance of jewelry.

They also give the finished products increased strength.

To obtain a nice chocolate shade, manufacturers practice special chemical processing of an alloy containing gold and copper components. In the jewelry industry, a material that is distinguished by its olive green hue is in high demand. Cadmium gives the alloy a rich emerald color.

Making raw materials with blue tints is the secret of master jewelers. Experts suggest that iron and cobalt are added to the metal alloy in various proportions. Black gold is considered truly exotic. Jewelers obtain the unusual shade by coating an alloy with a red tint with rhodium.

The appearance of the material largely depends on processes involving chemical effects on the composition of the raw material.

Source: https://blog.juveros-shop.ru/trappings/kak-sostav-zolotogo-splava-vliyaet-na-o/

An alloy is a homogeneous composite material. Properties of alloys

Everyone has heard the word “alloy”, and some consider it synonymous with the term “metal”. But these concepts are different. Metals are a group of characteristic chemical elements, while an alloy is the product of their combination. Metals are practically never used in their pure form, and they are difficult to obtain in their pure form. Whereas alloys are ubiquitous.

What is an alloy

Let's look at this issue in more detail. So, an alloy is a combination of several metals or one and various non-metallic additives. Such connections are used everywhere. An alloy is a macroscopic homogeneous system obtained by melting. They have been known since ancient times, when humanity, using primitive technologies, learned to produce cast iron, bronze, and a little later - steel.

The production and use of these materials is due to the fact that it is possible to obtain an alloy with specified technological properties, while many characteristics (strength, hardness, corrosion resistance, and others) are higher than those of its individual components.

Main types

How are alloys classified? This is done according to the type of metal that is the basis of the connection, namely:

1. Black. The base is iron. Ferrous alloys include all types of steels and cast irons.
2. Colored. The base is one of the non-ferrous metals. The most common non-ferrous alloys are based on copper and aluminum.
3. Rare metal alloys. Based on vanadium, niobium, tantalum, tungsten. They are used mainly in electrical engineering.
4. Alloys of radioactive metals.

Other elements - metals and non-metals - are added to the main component of the alloy, which improve its technological properties. These additives are called alloying additives. Alloys also contain harmful impurities - if their permissible value is exceeded, many of the material’s characteristics are reduced. So now you know what an alloy is.

Alloys are also classified into double, triple and others - according to the number of components. According to the homogeneity of the structure - homogeneous and heterogeneous. According to their distinctive properties - low-melting and refractory, high-strength, heat-resistant, anti-friction, corrosion-resistant and materials with special properties.

Mechanical properties

The mechanical properties of alloys determine the performance of the material when exposed to external forces. In order to determine the characteristics of the connection, the sample is subjected to various tests (stretched, scratched, loaded, a metal ball or diamond cone is pressed into it, studied under a microscope) to determine strength, elasticity, and ductility.

The composition of the alloy determines its physical properties. These include specific gravity, electrical conductivity, melting point, specific heat capacity, coefficient of volumetric and linear expansion. Also physical are the magnetic properties of alloys. They are characterized by residual induction and magnetic permeability.

Chemical

What are the chemical properties of the alloy? These are characteristics that determine how a material reacts to the effects of various active, including aggressive, agents. The chemical effect of the environment can be seen visually: iron is “eaten up” by rust, a green coating of oxides appears on bronze, steel dissolves in sulfuric acid.

In metallurgy and heavy engineering, many methods are used to combat the aggressive influence of the external environment: new, more resistant materials based on copper, titanium and nickel are being developed, alloys are coated with protective layers - varnishes, paints, oxide films, and their structure is improved. As a result of negative environmental factors, industry annually suffers damage amounting to millions of tons of steel and cast iron.

Technological

Manufacturability – what is it? In industry, an alloy is not needed on its own; it is used to make a part. Consequently, the material will be heated, cut, deformed, subjected to heat treatment and other manipulations.

Manufacturability is the ability of an alloy to be subjected to various methods of hot and cold processing, for example, melting, easily spreading and filling a casting mold, deforming in hot or cold form (forging, hot and cold stamping), welding, and processing with metal-cutting tools.

Technological properties can be divided into:

1. Foundry. They are characterized by fluidity - the ability to fill the mold for casting, shrinkage (the percentage of volume loss after cooling, hardening) and segregation - a complex process in which a heterogeneous structure of the material is formed in different parts of the casting.
2. Ductility. This is the ability of an alloy to deform under impact load and take the desired shape without loss of integrity. Some metals have good malleability only when hot, others - both cold and hot. For example, steel is forged while hot. Aluminum alloys and brass take the desired shape well at room temperature. Bronze is difficult to deform by impact, and cast iron is not ductile and is destroyed under the influence of a hammer (with the exception of malleable cast iron).
3. Weldability. Low-carbon steel has good weldability; this characteristic is much worse for high-alloy steels and cast irons.

Source: https://FB.ru/article/379872/splav-eto-odnorodnyiy-sostavnoy-material-svoystva-splavov

What metals is brass alloy made from?

Brass is an alloy of copper and zinc. The golden hue gives it a similarity to gold, but this compound is much cheaper. Pure copper is more expensive than brass. This is due to the lower cost of zinc, which is part of brass. The resulting alloy has characteristics that copper does not have at a lower price.

The alloy is resistant to environmental influences. However, it requires varnish to be applied to the surface, as it turns black over time. Due to its ductility and hardness, it is used both in industrial production and for the manufacture of costume jewelry as decorations.

What is brass

The main components of brass alloy are copper and zinc. The proportional components of these metals may be different. The amount of zinc varies. Its minimum value is 20%. The maximum reaches 50%. At the same time, the alloy changes its color: it can be golden, yellow or green.

The percentage of zinc is so important that it can change the characteristics of the material. This refers to its ductility and hardness.

Structure and composition

The composition of the alloy is formed from the phases:

1. Alpha phase. zinc up to 35%
2. Beta phase. The presence of zinc is up to 50%. The composition also includes tin - 6%.

In some cases, a single alpha phase is present. Depending on changes in the percentage composition of the main components, the structure of brass can simultaneously consist of 2 phases - alpha and beta.

The chemical composition of brass, in addition to copper and the main alloying element zinc, includes additives. These include alloying elements: aluminum, iron, manganese, lead, silicon, nickel. They make up a small percentage of the compound. Each of them affects the characteristics of the material.

Properties and characteristics

The main quality in the characteristics of brass is its corrosion resistance. But it also has other properties:

1. The ability of the alloy to withstand aggressive environments, especially after coating the surface with varnish.
2. Strength of brass.
3. Plasticity of the alloy.
4. The ability of the material to be processed by pressure. The process is carried out both hot at high temperatures and cold.
5. The alloy can be subjected to resistance welding and soldering.
6. Thermal conductivity, which increases with increasing percentage of copper.
7. Melting point, which is 880–950 degrees. With less zinc added, the melting point decreases.
8. The material has non-magnetic properties.

The main factor in the hardness and ductility of the joint is zinc.
An increase in its quantitative content is directly related to an increase in strength characteristics. Plasticity increases only up to a quantitative zinc content of 36%. With a subsequent increase to 45%, this indicator decreases. Brass. How to determine? Where to look?

In order to increase the hardness of the alloy, a heat treatment called cold hardening is carried out. It helps not only to increase the strength index, but also relieves internal, structural stresses.

Alloying additives affect the performance characteristics. Their influence is indicated in the table:

Name of alloying element	Effect on brass characteristics
Silicon	Its high presence leads to a decrease in the hardness of brass.
Lead	Improves anti-friction properties.
Manganese, aluminum and tin	Increases resistance to tearing. Corrosion resistance is increasing.
Nickel	Reduces the risk of material cracking. The alloy acquires a peculiar color. This connection is called “white brass”.
Arsenic	The material has the ability to work in liquid, fresh media.

Marking

There are 2 types of alloys:

1. Two-component. The main components are copper and zinc. They are marked with the letter L. Next are numbers indicating the amount of copper in percent. L60: contains 60% copper, and the remaining 40% zinc.
2. Multicomponent. In addition to the main components, alloying elements are added. Also in front is the letter L. Then follows a list of additives. At the end, numbers are written through a dash indicating the percentage of each component. The amount of zinc is not indicated, but calculated. For example: Brand LAZhMts66-6-3-2 has 66% Cu, 6% Al, 3% Fe and 2% Mn. By calculation, the amount of zinc is determined to be 23%.

Advantages and disadvantages

Brass alloy has characteristics that are positive in one case and negative in another. They consist of the following:

1. Light weight. This quality, together with high strength, is used in certain industries.
2. The alloy has good ductility.
3. Low cost.
4. Corrosion resistance decreases with increasing amount of copper.
5. Thermal conductivity indicators are lower than those of pure copper and bronze.

Production of material

All components that make up the alloy have different melting points. This creates difficulties when melting brass. During the work process, components are added in a certain sequence.

The production scheme looks like this:

1. Extraction of copper and zinc from ore.
2. Fuse. The copper is heated first, and then the other components.
3. Forming ingots by pouring molten metal into molds.
4. They arrive at the rolling shop, where the metal is processed in order to deform the ingots.
5. Annealing and etching.

Brass production. MADE.BY

Areas of application

Brass is used in the following areas:

1. Making jewelry from brass. Despite the fact that in the jewelry business only costume jewelry is made from it, the demand for such products is great.
2. Due to its plasticity, furniture decorations are forged from it. Fittings are also manufactured.
3. If the zinc content is 40%, the alloy is used in shipbuilding, watch movements and aircraft construction.
4. Water taps, mixers, and fittings are made from it.

How to distinguish gold from brass

Even though gold and brass look similar, there are ways to tell one from the other. This is checked as follows:

1. Gold has a more saturated color. In addition, over time, brass darkens because it oxidizes in air, but gold does not.
2. If you put a magnet near it, brass will be attracted, but gold will not.
3. Brass has a higher density, which means it is heavier. This is noticeable when throwing pieces of metal in your palms.
4. Availability of sample.
5. If you test with acid, the gold will not react and the brass will discolor.

From brass to gold one step

How can you tell the difference between a brass alloy and a bronze alloy?

Sometimes it is necessary to distinguish bronze from brass. Bronze bushings are used as bearings.

There are methods for this:

1. Bronze is darker in color and significantly heavier. This is noticeable when tossing.
2. Bronze products are harder. The area of ​​the chip will be coarse-grained. The fracture of the brass part will be smooth.
3. Take 2 test tubes with the reagent. Bronze shavings are placed in one, brass shavings in the other. After heating, a white precipitate will appear in the first. In the second, nothing will happen.
4. When brass shavings come into contact with sea salt, they change color. No bronze filings.

Brass is an alloy that is no longer possible to live without in everyday life. Metal is included in the technological process of many industrial parts, and it is not so easy to replace it.

What metals is brass alloy made from? Link to main publication

Source: https://metalloy.ru/splavy/latun

Pipe D16T: standard and material features

By what standards are thin-walled and thick-walled pipes D16t produced? What material is it made from? How does this material differ from alternative solutions? Let's figure it out.

Meet the hero of our today's material.

Raw materials

First, let's separate the flies from the cutlets. D16t is a marking not of the pipe itself, but of the alloy from which it is made. Like all aluminum alloys, ours has a low density (about 2800 kg/m3).

The main disadvantage of aluminum is its low mechanical strength, which is largely offset by the addition of other elements of the periodic table.

Compound

According to GOST 4784-97, alloy D16 has the following composition:

Metal	Mass fraction, %
Fe	Up to 0.5
Si	Up to 0.5
Mn	0.3 — 0.9
Cr	Up to 0.1
Ti	Up to 0.15
Al	90.9 — 94.7
Cu	3.8 — 4.9
Mg	1.2 — 1.8
Zn	Up to 0.25
Third party impurities	No more than 0.15 (maximum 0.05 for each)

Please note: the amount of aluminum in the alloy is approximate. This metal is the base; Under certain conditions, the upper content limit indicated in the table may be exceeded.

So, the main components of the alloy are aluminum and copper.

What characteristics does such a composition provide?

• D16 is noticeably harder than pure aluminum. However, like all duralumin alloys.
• Strength is fully maintained in the range of up to 250 degrees Celsius. Actually, in the range of 120 - 250C this alloy has no equal among all types of duralumin.
• The upper limit of short-term heating is about 500C.

Post-processing

Perhaps the reader noticed that the name of the alloy - D16 - differs from the one in the title of the article D16t in the absence of a letter at the end.

Blanks of alloys D16 and D16t.

It stands for post-processing method. The following options are possible:

Marking	Description
T	Hardened and naturally aged alloy
T1	Artificially aged
M	Annealed
A	Plated

Useful: in the price lists of manufacturers you can find markings like D16TA. This designates an alloy that has undergone hardening, natural aging and (after forming the part) plating.

Terminology

Some terms may need clarification.

• Annealing is heating to the recrystallization temperature (in our case, approximately 500C) followed by slow cooling. Without going into the physics of the process, we note that annealing gives metals increased ductility and toughness, and at the same time relieves internal stresses in metal structures.
• With rapid cooling from the recrystallization temperature to room temperature and below, the physical properties of the metal change in the other direction: on the contrary, it becomes extremely hard. The corresponding process is called hardening.
• Plating is the application of a layer of pure aluminum to the surface of the alloy. The fact is that it has greater corrosion resistance than many of its alloys; plating performs a protective function.

Broken cladding layer on a 5-ruble coin.

But the process of aging the alloy is so interesting that we will devote a separate section to getting to know it.

Aging

At the beginning of the 20th century (more precisely, a decade before the First World War, in 1903), the German materials scientist Alfred Wilm, an employee of the metallurgical factory Dürener Metallwerke AG, discovered an unexpected phenomenon while studying the properties of aluminum.

An alloy of 96% aluminum with 4% copper, after being quenched, like many other metals, quite predictably became harder and stronger. However, the process did not stop when the alloy reached room temperature: at 20C in the next 4-5 days, the metal continued to gain strength without losing its ductility.

The alloy was called duralumin (in honor of the German city of Duren, where its industrial production began in 1909), and its composition and heat treatment technology were quickly classified: at first it was widely used for the construction of frames for military airships.

The photo shows the German airship Graf Zeppelin. Duralumin was used to construct a rigid frame that made the aircraft resistant to gusts of wind.

However, the awl cannot be hidden in a bag: by 1920, duralumin had become the main material in aircraft construction around the world. During the experiments, another interesting property of the alloy was revealed: the process of gaining strength can be sharply accelerated by heating it after hardening to 188 - 193 degrees.

In this case, maximum strength was achieved in 11 - 13 hours, which, of course, from the point of view of manufacturability, looked much more advantageous.

How strong is the D16t alloy compared to pure aluminum? Let's compare their resistance to compressive loads: aluminum can withstand 7-8 kg/mm2, and duralumin 45.

Hardness, electrical and thermal conductivity of aluminum alloys.

There are a few more things to know about rafting.

Welding it is very problematic. As a rule, rivets are used to connect sheet parts with your own hands.

The rivets themselves are often made from the same D16t.

The priority area of ​​use of the alloy is aircraft construction; less often it is used for the needs of the automotive industry - mainly in the manufacture of bodies.

It cannot be called a cheap material. The price of the notorious pipes made from this type of duralumin is from 500 rubles per kilogram.

GOST 18482-79

Actually, let's get back to the pipes. They must be produced in accordance with GOST 18482-79 “Pipes pressed from aluminum and its alloys.”

Let's study the main provisions of the document:

• Pipes can be either round or shaped.

Several types of duralumin profiles.

• In terms of wall thickness, the standard provides for division only into thin-walled (wall up to 5 mm) and thick-walled (over 5 mm).
• The outer diameter for a round section, according to the assortment table contained in the standard, can vary from 18 to 300 millimeters . Maximum permissible deviations from the nominal size increase with increasing diameter and take values ​​from 0.5 to 2.8 mm up or down.
• The wall thickness can reach 93.116 millimeters with a 300 mm diameter.

Please note: the assortment table is not an immutable canon. Additional sizes may be introduced upon agreement with the supplier; In this case, tolerances are taken as for the smaller of the nearest diameters.

• The length of the products is from 1 to 6 meters: unmeasured, measured or multiple of measured . In the latter case, the instruction common to most similar standards applies: a 5-mm allowance is made for each cut. Interestingly, pipes made of softer alloys can be supplied in coils up to 15 kilometers long.

The hardness of the D16t alloy allows pipes to be supplied only in straight sections.

• Products with a wall thickness of over 10 mm and an outer diameter of 100 mm or more must not have burrs on their outer surface.

Conclusion

We will consider our acquaintance with the new material successful. We hope that it will be useful to the reader (see also the article “Pipe for underfloor heating: how to choose the optimal type and install it correctly”).

As always, the video in this article will offer additional information. Good luck!

Source: https://remstroymast.ru/tryba-d16t-standart-i-osobennosti-materiala.html

Metal alloys

Metals have been used by humans for many millennia. The defining eras of human development are named after the names of metals: the Bronze Age, the Iron Age, the Age of Cast Iron, etc. Not a single metal product around us consists of 100% iron, copper, gold or other metal. Each contains additives deliberately introduced by a person and harmful impurities introduced against the will of a person.

Absolutely pure metal can only be obtained in a space laboratory. All other metals in real life are alloys - solid compounds of two or more metals (and non-metals), purposefully obtained in the process of metallurgical production.

Classification of homogeneity of alloys

Classification

Metallurgists classify metal alloys according to several criteria:

1. manufacturing method:
2. production technology:
   • foundries;
   • deformable;
   • powder;
3. homogeneity of structure:

   Types of alloys based on them

4. type of metal - basics:
   • black (iron);
   • non-ferrous (non-ferrous metals);
   • rare metals (radioactive elements);
5. number of components:
   • double;
   • triple;
   • and so on;
6. physicochemical characteristics:
   • refractory;
   • fusible;
   • high strength;
   • heat resistant;
   • hard;
   • antifriction;
   • corrosion-resistant, etc.;
7. purpose:
   • structural;
   • instrumental;
   • special.

Metals and alloys based on them have different physical and chemical characteristics.

The metal having the largest mass fraction is called the base.

Properties of alloys

The properties possessed by metal alloys are divided into:

1. Structurally insensitive. They are determined by the properties of the components and their percentage. These include :
   • density;
   • melting temperature;
   • thermal and elastic characteristics;
   • coefficient of thermal expansion;
2. structurally sensitive. Determined by the properties of the element - the base.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/splavy-metallov.html

Alloys, their classification and properties

There are several ways to classify alloys:

• by manufacturing method (cast and powder alloys);
• by the method of obtaining the product (casting, wrought and powder alloys);
• by composition (homogeneous and heterogeneous alloys);
• according to the nature of the metal - base (ferrous - Fe base, non-ferrous - base, non-ferrous metals and alloys of rare metals - radioactive elements base);
• by the number of components (double, triple, etc.);
• by characteristic properties (refractory, low-melting, high-strength, heat-resistant, hard, anti-friction, corrosion-resistant, etc.);
• by purpose (structural, instrumental and special).

Main types of alloys

Various steels, cast iron, alloys based on copper, lead, aluminum, magnesium, as well as light alloys are widely used among all kinds of alloys.

Steels and cast irons are alloys of iron and carbon, with the carbon content in steel up to 2%, and in cast iron 2-4%. Steels and cast irons contain alloying additives: steels – Cr, V, Ni, and cast iron – Si.

There are different types of steels; for example, structural, stainless, tool, heat-resistant and cryogenic steels are distinguished according to their intended purpose. Based on their chemical composition, they are divided into carbon (low-, medium- and high-carbon) and alloyed (low-, medium- and high-alloy). Depending on the structure, austenitic, ferritic, martensitic, pearlitic and bainitic steels are distinguished.

Steels have found application in many sectors of the national economy, such as construction, chemical, petrochemical, environmental protection, transport energy and other industries.

Depending on the form of carbon content in cast iron - cementite or graphite, as well as their quantity, several types of cast iron are distinguished: white (light color of the fracture due to the presence of carbon in the form of cementite), gray (gray color of the fracture due to the presence of carbon in the form of graphite ), malleable and heat resistant. Cast irons are very brittle alloys.

The areas of application of cast iron are extensive - artistic decorations (fences, gates), cabinet parts, plumbing equipment, household items (frying pans) are made from cast iron, and it is used in the automotive industry.

Copper-based alloys are called brasses; they contain from 5 to 45% zinc as additives. Brass containing 5 to 20% zinc is called red (tompak), and brass containing 20–36% Zn is called yellow (alpha brass).

Among lead-based alloys, two-component (lead alloys with tin or antimony) and four-component alloys (lead alloys with cadmium, tin and bismuth, lead alloys with tin, antimony and arsenic) are distinguished, and (typical of two-component alloys) with different contents of the same components different alloys are obtained. Thus, an alloy containing 1/3 lead and 2/3 tin - tertiary (ordinary solder) is used for soldering pipes and electrical wires, and an alloy containing 10-15% lead and 85-90% tin - pewter, was previously used for casting cutlery.

Aluminum-based two-component alloys – Al-Si, Al-Mg, Al-Cu. These alloys are easy to produce and process. They have electrical and thermal conductivity, are non-magnetic, harmless in contact with food, and explosion-proof.

Aluminum-based alloys are used for the manufacture of lightweight pistons; they are used in carriage, automobile and aircraft construction, the food industry, as architectural and finishing materials, in the production of technological and household cable ducts, and in the laying of high-voltage power lines.

Examples of problem solving

Source: http://ru.solverbook.com/spravochnik/ximiya/9-klass/splavy/

Alloys - Chemistry

Metals have been used by humans for many millennia. The defining eras of human development are named after the names of metals: the Bronze Age, the Iron Age, the Age of Cast Iron, etc.

Not a single metal product around us consists of 100% iron, copper, gold or other metal.

Each contains additives deliberately introduced by a person and harmful impurities introduced against the will of a person.

Absolutely pure metal can only be obtained in a space laboratory. All other metals in real life are alloys - solid compounds of two or more metals (and non-metals), purposefully obtained in the process of metallurgical production.

Classification of homogeneity of alloys

Alloy and composite 2020

Both alloys and composites are at least two mixtures of components. However, there are also several differences between them that make them suitable for different applications. An alloy is a combination of two or more components, one of which must be metallic.

The goal of combining these two (or more) ingredients is to create a mixture that has significantly different (better) qualities than the isolated components. However, current technologies often have requirements that cannot be met by conventional alloys.

Today, many industries require materials that have higher mechanical properties, such as low density, high strength, resistance to abrasion and corrosion. This combination of properties can be realized using composite materials.

Composites are similarly a combination of two or more ingredients, but metals are not necessarily included in their formation. These constituents (which are physically and chemically diverse) combine to create a composition that is stronger than the original elements. In addition to synthetic (artificial) composites, there are also natural composites (eg wood, bone and teeth).

What is an alloy?

Metals and alloys are materials that are characterized by a number of specific features, thanks to which they have become the basis of modern technologies. Metals are composed of a pure chemical element with a small amount of other elements added.

They are characterized by a characteristic metallic luster, increased electrical and thermal conductivity, good mechanical properties, resistance to electrochemical influences and elevated temperatures, susceptibility to processing (processing) of various technologies in cold and heated conditions, etc. All of these characteristics are due to the properties of the internal structure of atoms and their relationships.

The density of the metal is 0.59 g/cm3 (lithium) and 22.4 g/cm3 (osmium). The metal with the highest melting point is tungsten (34000C), and mercury has the lowest (-390C).

Alloys are complex materials consisting of a base element and metals or non-metals. Alloying elements are called alloy components, and their quantities and characteristics determine the complexity of the alloy and its characteristics. The metal (at least one) is part of an alloy (eg bronze: copper and tin alloy, steel: iron and carbon alloy, etc.).

Alloys take on entirely new characteristics that differ from those of their components: more favorable mechanical properties, increased corrosion resistance, color change, improved machinability, etc.

Most alloys are produced by melting the components, but there are other methods such as well - this is the case of cermet alloys, which are produced by sintering.

In industrial practice, pure metals are often replaced by alloys. There are several reasons: commercially pure metals are difficult to obtain in a purified state, they are expensive, typically have low damping capacity and strength levels, unfavorable chemical and physical properties, often difficult to handle with standard processing methods, and many others.

What is a composite?

Composites are formed from composite materials, e.g. by casting, lamination or extrusion. A composite material is a material consisting of a combination of two or more simple (monolithic) materials and in which the individual components retain their distinctive identity. A composite material has properties that are different from those of its components—simple materials.

This often means that the physical properties are improved, since the main technological interest is in obtaining materials with superior physical (usually mechanical) properties relative to the properties of the components. In principle, there are two phases (components) in a composite material: matrix and reinforcement. These segments have significantly different mechanical properties.

The matrix is ​​softer and serves as a filler to achieve shape stability of the solid phase. Reinforcement is a hard and rigid component. Depending on the matrix, composites are divided into: metals, ceramics and polymers. All components may be continuous or may be dispersed in a continuous matrix.

In the latter case, it is necessary to set a lower limit on the size of the dispersed phase, below which the material is considered monolithic. Examples of commonly used composites are:

• particle-added—solid aluminum oxide particles of aluminum oxide Al2O3 or silicon carbide SiC bonded to a glass or polymer matrix in a solid plate;
• with the addition of fiber - plastic (epoxy or polyester resin) reinforced with fiberglass;
• structural composite - alternating layers in “plywood” of thin layers of wood and wood glue (polymer).

Alloys have the following advantages:

• light weight
• excellent fatigue resistance
• high temperature resistance
• extremely long lasting
• low ductility or no ductility compared to metals, which warp and mold caused by high stress
• can provide strength to weight ratio up to 20%
• more resistant to stress during thermal activity, since they have almost no thermal expansion and retain their original shape as the temperature increases
• offer the possibility of connecting parts during the production process itself
• Corrosion resistant, durable and dimensional stable under extreme operating conditions
• Non-metallic composite materials are non-magnetic and can be used in the environment of sensitive electronic components. Additionally, they are not electrically conductive, so they can be connected to electronics

Difference between alloy and composite

An alloy is a combination of materials - a mixture of two or more metals or a metal with a non-metallic element. Its physical properties are intermediate between the physical components of metals; but the chemical properties of each element remain unaffected. The mixture can be separated by physical means. A composite is also formed from several elements (metal can be part of the mixture, but does not have to be). Elements can be returned to their original state by chemical reactions.

An alloy is essentially the same material with additional properties. Mixtures are formed from components in order to achieve higher quality than the components.

An alloy permanently changes the physical characteristics of metals, and some of the benefits that can be achieved are increased resistance to corrosion and oxidation, changes in electrical properties, improved strength, higher or lower melting points compared to the constituent metals, and so on.

A composite is a combination of materials to form a completely new material (with changed qualities). The new material may be stronger, lighter, or less expensive than the original components.

Depending on the structural compounds and methods/techniques used in the manufacturing process, both alloys and composites exhibit different characteristics and can have different applications accordingly.

Alloy vs composite

alloy	composite
a mixture of metals or a mixture of a metal and another element	a composite is a custom-made substance of any combination
the introduced element (solute) dissolves in the alloy receiving the alloy (solvent) to form a solid solution. Cannot be distinguished	the component forming the base of the composite (matrix) and the added element remain undissolved and can be identified.
homogeneous mixture	can be homogeneous or heterogeneous
the constituent elements do not retain their original properties	the materials forming the composite retain their original properties
have completely different improved properties than the reagents	carry traces of elementary characteristics
do not have strict proportions in elemental composition	have strict proportions in elemental composition

Summary

• Sometimes pure metals do not have satisfactory mechanical and technological properties (for example, for the manufacture of machine elements and tools and in the construction industry) and are therefore not used as such. This is where alloys and composites have proven to be very important
• Alloys are composed of at least two components, in which the main component is a metal, while the other components may be metallic as well as non-metallic. The new material provides enhanced characteristics such as better corrosion resistance, increased conductivity, lightness, greater cost efficiency, etc.
• A composite material is a system consisting of two or more components with different configurations, one of which is a matrix or base material (polymer, ceramic or metal), to which a second component (fiber, nanotube, spherical particle) is added to achieve the desired combination properties (stiffness, density, rigidity, hardness, thermal and electrical feasibility).
• Both alloys and composites have many advantages, depending on the materials and technologies used. Some of the improvements are light weight, high strength and durability related to weight, corrosion resistance, high impact resistance, dimensional stability, durability, etc.

Source: https://ru.esdifferent.com/difference-between-alloy-and-composite

How to get humus from grass?

Most farmers prefer organic fertilizers, not least of which is compost. But not everyone knows how to make humus from grass and other components so that it does not rot. Creating high-quality organic matter is a whole science.

What is garden compost?

Summer residents call compost “garden gold.” It is used as mulch and fertilizer. The use of humus helps increase plant fertility, retain moisture in the soil and protect against diseases.

Compost can be prepared from organic matter of animal and plant origin, placed in a common heap. The process of decay involves microorganisms that decompose the collected waste. Among the symbiotes one can also distinguish worms and insects.

Garden compost

How to make compost?

There are factories where organic components are processed. The conditions created there make it possible to obtain mature compost within a day. For summer residents, the process will take longer and will require compliance with a number of rules.

How compost is mixed

Humus is not created immediately - it is formed over several months, placing organic matter on top of each other. In this case, each new layer is made no thicker than 70 cm. But it should not be compacted - the materials should lie freely. Moisture is necessary for the rotting process to begin, so the pile is periodically watered.

Important! To ensure oxygen penetrates into all layers, they are shoveled with a pitchfork. This will save the plant being fed from fungal diseases.

To ensure that the compost always remains moist, the heap must be prepared in a volume of at least a cubic meter. For the same reason, shaded areas are designated as the place for humus. It is advisable to keep the compost covered to prevent rain from washing away the nutrients. The covering material is selected in such a way that the organic matter does not overheat, otherwise the bacteria will die.

Accelerated composting

For those who are wondering how to quickly make humus from grass, it is suggested to use the hot composting method. Its essence lies in the fact that organic matter in the heap is transferred frequently - almost every week.

To do this, additional space is allocated nearby where layers of humus will be transferred. With hot composting, organic fertilizer is ready in a month.

Those who don’t want to handle a pitchfork are encouraged to pay attention to an original way to make compost from grass - something like a concrete mixer is built from a metal barrel. Its ends are fixed to the axis, the grass is placed through a door made in the wall. It will be enough to come up and turn the barrel a little.

If you choose a 200 liter container, then you simply roll it on the ground. Metal containers must have holes for air access. It is not recommended to pour water - it is better to place already moistened material inside.

Hot composting technique

Additional Information. The rate of decay also depends on the components themselves. The smaller they are used, the faster the microorganisms will cope with the task.

Acceleration Supplements

Experienced summer residents give advice on how to speed up the composting of grass. You can use a regular seed from ready-made humus. They layer the pile with it, and rotting proceeds faster.

On a note! There are also special means for humus grass. Biological products such as “Baikal EM” and “Doctor Robik” make it possible to obtain compost in a few weeks.

What is added to compost

Compost heaps are layered with various organic matter, which is classified into 2 types: green and brown. Each material has its own characteristics of “behavior” and the role assigned to them in the compost.

Green component

Green components

This organic matter saturates the humus with nitrogen. Rotting occurs quickly, with heating, but is usually accompanied by an unpleasant odor.

What's in green organics?

ViewNote

Natural fresh greens: grass, fallen leaves, weeds, tops	· Weeds must be mowed before they are seeded, so as not to have to worry about weeding the beds;
· It is better not to use tops from diseased crops;
· All greenery is pre-withered so that the material in the compost is not sour. Otherwise you will end up with toxic silage.
Hay	· This is an excellent material for humus, but it must not only be moistened with water, but also additionally watered with herbal infusions or transferred with other components;
· The best time to mow grass for hay is autumn
Fruit and kitchen waste	A thin layer of crushed materials is allowed
Manure	· Horse straw is desirable. Pork should be avoided - it is too sour;
· Needs a layer of straw and food waste;
· Before laying in the beds, it is better to lime such compost with fluff
Chicken droppings	Not recommended in a combined heap. It is better to compost separately, for use as liquid fertilizers.
Feces	· Add in small quantities - twice a month;
· Pre-dilute with water and ferment for a week. Then this mixture is poured over the pile. Ash is sprinkled on top and a grass floor is made.

If the summer resident has enough green materials, then it is not necessary to supplement them with brown ones, or you can make light layers.

To make compost from grass, the preparation of raw materials is carried out according to all the rules: it must be mowed in dry, warm weather. As soon as mowing is completed, you should not immediately send the raw materials to the compost - let them dry out a little in the sun.

Organic brown

This raw material is depleted in nitrogen, but provides plants with a lot of fiber. This includes straw, dry leaves, corn cobs, chaff, seed husks, sawdust, tree bark and even paper. Those who grow mushrooms on their farm can safely use the remains of oyster mushrooms as brown fertilizer.

Important! These materials decay slowly and, during the process of decay, absorb nitrogen needed by microorganisms. Therefore, these components cannot be composted on their own. Or the heap is regularly moistened with urea - 2 kg per 1 cubic meter.

Brown organic matter for compost serves as a loosening agent: it ensures the porosity of the heap and retains moisture and air inside.

Brown organics for compost

What not to compost

Not all organic matter and waste can be composted. Meat and dairy products do not so much rot as they turn sour, saturating the air with an unpleasant odor that attracts rats and other animals.

Important! Do not dump household waste here either. A compost heap is not a landfill, but a storage of nutritious fertilizers for cultivated plants.

What containers are suitable?

When deciding how to make compost from grass and weed clippings, as well as other raw materials, they look for a suitable place for this.

Some people start digging holes, which is not worth doing for a number of reasons:

• excess water will accumulate;
• in such conditions it is impossible to properly mix the pile;
• poor air access, which will prevent proper rotting.

The best option is homemade boxes 1 m high. They are missing one wall - for convenient access to the pile. It is advisable to make the floor lattice so that air can be sucked in from below. Then composting will be fast and high quality. If you plan to simply fence the area with 3 walls, then sawdust or straw is first laid on the ground.

Compost bins

An excellent option would be a barrel; it has holes for air penetration. But it should be roomy enough so that the grass does not have time to dry out. It is more rational to use both options - this will ensure continuity of preparation of nutritious fertilizers.

You can also use a bag for humus, but this is not a very convenient option - small volumes and poor air access.

How do you know when the compost is ripe?

Regardless of whether humus is made exclusively from grass, or other components are used in composting, readiness is judged by the pleasant smell emanating from the heap, reminiscent of the aroma of forest litter.

Interesting! They also pay attention to the color of the compost - it should be uniformly dark, almost black. At the same time, ready-to-use organic matter has a crumbly structure.

How is compost different from humus?

When talking about organic fertilizers, many gardeners perceive the words “humus” and “compost” as synonyms. Others, on the contrary, consider these to be separate varieties.

Going deeper into the details, the following points should be highlighted:

• humus is rotted manure that acquires an earthy, loose mass; it may contain impurities of straw and grass;
• Compost is already a combination of 2 or more components, stacked in layers.

How is compost different from humus?

If you call compost humus, there won’t be a big mistake - in both cases, organic matter is over-rotted.

Recipes

You can purposefully select the composition of the compost, enhancing the nutritional properties of humus. Experienced summer residents offer a time-tested recipe.

From chicken droppings

• 10 kg of straw is soaked for 2 days;
• the same amount of litter is divided into 3 parts and placed in a container, layered with straw and moistened with urea;
• after a week, they are shoveled, sprinkled with alabaster and fermented for another 7 days.

Before use, dilute with water 1:2. After application under the plants, it is recommended to sprinkle with soil.

Chicken manure compost

From slurry

Liquid compost made from manure, without adding any impurities, is most valued in agriculture. To ripen, the slurry is placed in a container (for example, a barrel) and mixed thoroughly every 3 days, keeping it for 2 weeks. Increasing the temperature will help speed up the fermentation process.

Important! To avoid burning the plants, the compost is diluted with water in a ratio of 1:3 before use.

Mistakes made by gardeners

Beginner agricultural technicians sometimes make mistakes when preparing humus. Some people forget to drain the accumulated water, and the compost heap begins to rot. Others place only carbon or nitrogen-containing components, which leads to a poor-quality humus composition. Still others take weeds along with seeds, which then cause them to sprout in the beds.

Knowing how to properly make compost from cut grass and other organic matter, you can hope that your dacha will always delight you with high yields.

Source: https://chudoogorod.ru/raznoe/kak-poluchit-peregnoj-iz-travy.html

Crown cobalt chrome. Replacing the tab. Single crown in the anterior segment

Metal-ceramic crowns based on cobalt-chrome have undeniable advantages:

• High strength
• Reasonable price
• Great looks.

The metal does not corrode and has significant strength

What is a group of teeth? Please give an example

A group of teeth is, for example, the teeth of the upper or lower jaw, or, for example, a grouping of teeth by type of teeth (molars, premolars, etc.)

Are they used together in 1 crown? Or are these crowns of different types?

Cobalt - chrome is used as the frame of the crown, and on top there is a layer of ceramics, used in one crown

In what cases is the treatment period extended to 14 days?

If there is a need to treat the tooth and install a stump tab under the crown.

How to care for it and increase its service life?

It is necessary to maintain personal hygiene 2 times a day, professional hygiene 2 times a year and visit the dentist for preventive examinations.

Metal-ceramic crowns are suitable for prosthetics on natural teeth and implants. The prosthesis consists of a metal frame, which is coated on the outside with ceramic material. The metals used in the construction are:

• Medical;
• Precious (gold, platinum).

A popular type is an alloy of cobalt and chromium; among all alloys, it has a minimal risk of patients developing an allergy to the metal. And the use of gold alloy eliminates allergic reactions.

Advantages and disadvantages

• Harmless to the patient
• High structural strength
• Affordable price.
• Possibility of single prosthetics, bridges, partial and complete dentures.
• Aesthetics (the color of the ceramic coating is selected to match the surrounding dental elements).

Disadvantage: Galvanizing effect if there are other metals in the mouth.

Metal-ceramic crowns based on

cobalt-chromium

no hidden fees

for your comfort

initial consultation with a doctor

• cash
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• cashless payments
• Alfa Bank loan

• with great experience
• graduated
• participation in conferences

You may also be interested in:

You can verify the good aesthetics of the dentures by reading patient reviews and looking at photos of metal-ceramic crowns based on cobalt-chrome.

Stages of treatment

Cobalt-chrome cermets are installed in several stages:

• Preparing a diseased tooth – depulping, grinding.
• The clinic doctor makes impressions for making future crowns (the patient chooses the color together with the dentist)
• Installation of a temporary “cap”, since the production of a permanent one takes up to 2 weeks.
• Installation of a permanent “cap”.

• restoration of lateral teeth,
• placement of bridges, permanent prostheses,
• replacement of worn crowns.

Prosthetics with metal-ceramics based on cobalt-chrome in Moscow clinics costs approximately 13,000 rubles.

No special care is required for the restoration structure. It is enough to regularly perform standard hygiene procedures.

Cobalt-chrome crowns

Crowns made of cobalt-chromium alloy are metal-ceramic products. This means that several materials are used to create a composite structure. By combining bases with different properties, dentists obtain a unique combination of the positive aspects of both types of raw materials.

In the case of crowns based on cobalt-chrome, the following advantages are obtained:

– high strength of the metal frame, which can withstand loads during the process of biting and chewing food, such as bending, loosening and methodical abrasion;

– excellent appearance, which can be brought into perfect harmony with the preserved units of the oral cavity or any individual wishes of the client;

– relative affordability compared to some alternatives. Well-developed, optimized processing techniques and the cost-effectiveness of the raw materials themselves make it possible to achieve acceptable performance.

Physical and chemical properties

The set of alloy parameters completely depends on the constituent elements.

In the case of dental cobalt chromium, these are the following components:

– base in the form of cobalt. The element must be at least 66-67 percent; it is responsible for the increased mechanical properties of the resulting metal;

– chromium is in second place, it should be at least 26-30 percent. The component is responsible for increased hardness and improved resistance to oxidative processes and corrosion;

– Nickel is the third most important, it is responsible for increasing technological parameters. At a percentage within 3-5 percent, the material becomes more malleable, ductile and viscous. Aspects make it possible to obtain a simpler substance in terms of release;

– molybdenum gives the structure a fine grain, which has a positive effect on the strength characteristics. The element can be added no more than 4-5.5 percent;

– manganese serves to solve a whole range of problems. Firstly, it increases the strength parameters of finished products. Secondly, the quality of casting increases due to the modernization of the alloy structure. Thirdly, the melting point of the substance drops noticeably, which is beneficial under production conditions and subsequent processing. Fourth, sulfur compounds, which are considered toxic to humans, are removed.

Two more components that can be found in blanks are beryllium and gallium. The problem is that the components are toxic and during operation can release a large amount of harmful substances, some of which can be accumulated by the body. The production of such products is carried out only by the USA, adding within 2% to the composition for the purpose of alloying it. You won't find such products in Europe.

These first three elements are the main ones, thanks to them the alloy matrix is ​​formed, therefore cobalt-chromium-nickel should be at least 85%. The data is fixed by an international standard, therefore, when purchasing a workpiece of any brand, you can expect consistently high quality and similar characteristics. If components break during molding, the chromium content threshold of 30 percent is most likely exceeded, which causes the alloy to become brittle and the mechanical and casting parameters to drop.

Another important element is carbon, however, it is not found in all products. Its positive quality is an increase in fluidity in the molten state and a decrease in the melting point.

Nitrogen and silicon have a similar effect, but they need to be added in a very small percentage:

– no more than 0.1 percent for the first;

– up to 1% for the second.

If this threshold is exceeded, plasticity will suffer.

Due to these weaknesses, a number of companies, including many domestic ones, are engaged in the production of carbon-free billets.

If the composition is observed, the finished material has a mechanical viscosity twice that of gold. Metal melts at more than 1450 degrees.

Application

The specified class of products (crowns) is far from the only use case. The raw material is also suitable for bridges and prostheses with bases made using the casting method; abutments can be made from it. Some types of clasp systems also use an alloy, however, it has insufficient strength characteristics. In most cases, to avoid premature failures, more reliable types of raw materials are used.

Restorative systems of this class are suitable in case of partial or complete tooth loss. For more complex cases, complete non-removable components with a cast base and bridge structures are selected. The first option is relevant if it is not possible to reliably fix the filling material, for example, the unit is severely damaged.

Negative sides

It is worth noting that the alloy is not used in some countries, however, this applies exclusively to the potentially dangerous ones produced by the United States. There are also negative aspects to harmless compounds, but they are more modest and do not lead to the accumulation of poison in the body.

First of all, it is worth noting that for absolutely any material that enters the human oral cavity, enzymes, temperature changes, humidity and some chemical elements are destructive. The difference is how and how much the prosthesis can resist them. The elements described above in the composition of the metal protect it and extend its service life, but in this case it is impossible to completely stop the process.

The metal in the mouth also undergoes a galvanic reaction, forming an unpleasant sensation and taste in the mouth. High-quality dentures make it possible to eliminate the occurrence of such problems during the entire period of operation, but it is necessary to periodically visit a doctor to assess the condition of the implemented structure (a general requirement for any dental systems). After exceeding the period, the risk of metal oxidation and the scale of the process increases.

Corrosion is also a problem for allergy sufferers, since the resulting products can provoke negative reactions in the body.

It has been proven that metals in the oral cavity affect the ionic composition of saliva. In order to avoid such problems, it is worth using only high-quality, proven suppliers of workpieces and established service life.

A very dangerous aspect of beryllium and gallium is the ability of the released harmful substances to accumulate. They are deposited in tissues and over time can affect the general condition, therefore all doctor’s instructions must be followed strictly. It is especially important not to exceed the established service life.

Also, for installation, you will need to grind the preserved unit to create a stump. Obviously, this increases the complexity of the operation and may affect the cost.

External manifestations in patients with a long period of wearing crowns are not uncommon - a blue base of soft tissues located in close proximity to the artificial product.

It is worth noting that often the source of problems with corrosion and galvanic reactions are different metals integrated into the oral cavity. The background is especially increased in the case of a combination of stainless steel prostheses and the alloy in question. Therefore, during the examination, the dentist must identify such inconsistencies and eliminate them; the patient, in turn, provides all the necessary information.

Source: https://dobriydoc-krd.ru/informacziya/koronka-kobalt-hrom-zamena-vkladki-odinochnaya-koronka-vo-frontalnom-segmente