Metals that are not magnetic

How to identify metal: types of tests, use of chemistry

Probably everyone had to hold in their hands a piece of jewelry or another object, obviously metal.

But how can you determine what metal is used in production? It could be a precious material or a counterfeit, or even a trinket with no claims to value. Expertise from specialists will give you the exact answer, but it is not free.

But there are methods for approximately determining the type of metal at home. They were used a long time ago, but they have not lost their relevance in our time.

Magnet check

Bringing a magnet close to the item being tested is a good way to perform initial testing. By the reaction of the magnet you can determine which group the metal belongs to:

1. Ferromagnets. The magnet is clearly attracted to the object, which means that the product may contain iron, steel or nickel.
2. Paramagnetic materials. The interaction with the magnet is very weak. This group includes aluminum and chrome. Precious metals that are paramagnetic are platinum, palladium and silver.
3. Diamagnets. In general, they do not react to magnets. Copper and zinc have these properties. Precious metals - gold.

Magnet check

Of course, such a check will not allow us to accurately determine the material from which the item is made. After all, a non-magnetic metal may not be in its pure form, but in the form of an alloy with a ferromagnet. But it can confirm or refute the assumption. For example, if it is checked whether it is gold or not, but the item is clearly magnetic, then it can be argued that it is a fake.

When checking jewelry, you should take into account that, in addition to precious metals, they may contain clasps, built-in springs, made of another material. You need to check the metal itself.

Heat check

You can also determine the group of a metal by how it conducts heat. It is known that the thermal conductivity of silver is very high. It is almost five times higher than that of iron or platinum. Slightly worse for gold, copper and aluminum. Platinum transfers heat even weaker than iron.

If you immerse the metal in hot water for 15–20 seconds, then based on its temperature, determined by touch, you can draw some conclusions.

1. Gold and silver objects will become as hot as the water in which they were dipped.
2. During this time, platinum and items containing iron will become warm, but not hot.

In this way it is easy to distinguish platinum from silver. But it’s not possible to compare silver or aluminum alloy.

Iodine test

You can check the authenticity of the metal using an iodine solution purchased at a pharmacy. A drop of iodine is applied to the surface and left for several seconds. Iodine will not harm noble metals - gold, platinum, silver. If the color of a drop of iodine does not change, and after removing it with a napkin, no traces or stains remain, this indicates the authenticity of the metal. If darkening is visible at the place of the drop, then this is a low-quality alloy or an outright fake.

Iodine testing of gold

Vinegar test

Household vinegar solution also does not affect precious metals. And it is dangerous for counterfeits. But, unlike the iodine test, acetic acid takes time. To wait for the result, you need to immerse the metal being tested in a container with vinegar for 15–30 minutes. The absence of traces of interaction between metal and vinegar is a sign of nobility.

If, in addition to metal, the product contains precious or semi-precious stones, then it is better not to check them this way; vinegar can ruin them. This is especially true for pearls.

Dental check

From novels and films we know that they used to test the authenticity of gold coins by biting them. What exactly can be installed in this “old-fashioned” way? Gold is a soft metal. Therefore, even with a weak bite, a dent from the teeth remains on it. Fake alloys do not have this property; you cannot take them with your teeth.

Such a test gives good results for high-quality products. The higher the pure gold content, the softer it is. Gold of 900 purity and higher is so soft that they try not to expose valuable items made from it to contact with other objects.

This is how you can compare platinum and silver. The latter does not have the softness of gold, but a strong bite may leave a small dent. It is impossible to leave marks with teeth on real platinum.

Application of chemicals

Testing with active chemical reagents should be left as a last resort. If handled improperly, they will damage even genuine precious metal. And they can be dangerous for the health of the inspector.

Ammonia

Pure gold does not react to ammonia. But practically no products intended for use are made from gold 900 and 999, only for collections. And on a precious metal of lesser purity, ammonia can leave an irremovable mark. Its solution in combination with other substances is used to clean gold items. Therefore, it is not worth identifying gold and silver items using ammonia.

Platinum products are usually produced with a high purity. Therefore, you can check the authenticity of platinum with ammonia. This chemical will not leave a mark on her.

Nitric and hydrochloric acids

Separately, these acids do not affect high-grade gold and platinum. And if you mix their concentrated solutions in a ratio of 1:3, you get a mixture called aqua regia. It can even dissolve gold. Aqua regia does not “take on” platinum when it is cold. This precious metal will gradually dissolve in the heated mixture.

Oddly enough, royal vodka is not afraid of genuine silver. It reacts to it by forming silver chloride in the form of a thin film on the surface. The latter protects the product itself from destruction.

Density check

One of the reliable ways to determine the type of metal or alloy is to determine its density. For pure gold it is two times higher than for copper and almost three times higher than for iron. Platinum is even heavier than gold. Even an alloy of 585 gold is noticeably heavier than base metals.

Of course, to determine the exact density of a small product you will need pharmaceutical scales, volume calculations (Archimedes' law to help) and tabular data on the density of base metals. But to solve the question of what the alloy is mainly made of, gold or another metal, rough estimates are sufficient. If you have at hand an object made of obviously genuine metal of approximately equal volume, then you may not even need a scale. A weight difference of two to three times is not so difficult to catch.

Separately, each of the considered methods will not give an exact answer to the question of what metal the product is made of. But if several different tests show the same results, you can be confident in the correct determination. If not, then you will have to turn to professionals.

Source: https://DedAntikvar.com/interesnoe/sposoby-opredeleniya-metalla

Magnetic stainless steels and corrosion resistance

Are there magnetic stainless steels and how does this affect corrosion resistance?

There is no clear answer to the question of whether stainless steel is magnetic, since the magnetic properties of alloys are determined by the properties of their structural components.

Classification of materials according to their magnetic properties

Bodies placed in a magnetic field become magnetized. The magnetization intensity (J) is directly proportional to the increase in field strength (H):

J= ϰH, where ϰ is a proportionality coefficient called magnetic susceptibility.

If ϰ>0, then such materials are called paramagnetic, and if ϰ

Some metals - Fe, Co, Ni, Cd - have extremely high positive susceptibility (about 105); they are called ferromagnets. Ferromagnets are intensely magnetized even in weak magnetic fields.

Stainless steels for industrial use may contain ferrite, martensite, austenite, or combinations of these structures in different proportions. It is the phase components and their ratio that determine whether a stainless steel is magnetic or not.

Magnetic stainless steel: structural composition and grades

There are two phase components of steel with strong magnetic characteristics:

• Martensite, from the point of view of magnetic properties, is a pure ferromagnet.
• Ferrite can have two modifications. At temperatures below the Curie point, it, like martensite, is ferromagnetic. High temperature delta ferrite is paramagnetic.

Thus, corrosion-resistant steels, the structure of which consists of martensite, are magnetic stainless steel. These alloys react to magnets like regular carbon steel. Ferritic or ferritic-martensitic steels can have different properties depending on the ratio of phase components, but, most often, they are ferromagnetic.

This category includes chromium and some chromium-nickel steels. They are divided into the following subgroups:

• Martensitic steels are hard and can be strengthened by quenching and tempering, just like regular carbon steels. They are used mainly for the production of cutlery, cutting tools and general mechanical engineering.

Steels 20Х13, 30Х13, 40Х13 martensitic class are produced mainly in a heat-treated ground or polished state

Chromium-nickel martensitic steel 20Х17Н2 has higher corrosion resistance than 13% chromium steels. This steel is highly manufacturable - it lends itself well to stamping, hot and cold, can be processed by cutting, and can be welded by all types of welding.

• Ferritic steels of type 08Х13 are softer than martensitic steels due to their lower carbon content. One of the most consumed ferritic steels is the magnetic corrosion-resistant alloy AISI 430, which is an improved analogue of grade 08Х17. This steel is used for the manufacture of technological equipment for food production, used for washing and sorting food raw materials, grinding, separating, sorting, packaging, and transporting products.
• Ferritic-martensitic steels (12X13) have martensite and structurally free ferrite in their structure.

Non-magnetic stainless steel

Non-magnetic alloys include chromium-nickel and chromium-manganese-nickel steels of the following groups:

• Austenitic steels occupy a leading position in terms of production volume. Non-magnetic stainless steel of the austenitic class is widely used - AISI 304 steel (analogue - 08Х18Н10). This material is used in the production of equipment for the food industry, the manufacture of containers for kvass and beer, evaporators, cutlery - pots, pans, bowls, kitchen sinks, in medicine - for needles, marine and refrigeration equipment, plumbing equipment, tanks for various liquids composition and purpose and dry substances. Steels 08Х18Н10, 08Х18Н10Т, 12Х18Н10Т (used in hardware A2), 10Х17Н13М2Т (used in hardware for use in aggressive environments, acid-resistant and salty, A4) have excellent manufacturability and high corrosion resistance even in chemical production vapors and ocean waters.
• Austenitic-ferritic steels are characterized by a high chromium content and a low nickel content. Additional alloying elements are molybdenum, copper, titanium or niobium. These steels (08Х22Н6Т, 12Х21Н5Т, 08Х21Н6М2Т) have some advantages over austenitic steels - higher strength while maintaining the required ductility, greater resistance to intergranular corrosion and corrosion cracking.

The group of non-magnetic materials also includes corrosion-resistant austenitic-martensitic and austenitic-carbide steels.

Method for determining whether non-magnetic steel is corrosion resistant

As the information presented above shows, there is no clear answer to the question – is stainless steel magnetic or not?

If steel is magnetic, can you tell if it is corrosion resistant? To answer this question, you need to clean a small area of ​​the part (wire, pipe, plate) until it shines. Two or three drops of a concentrated solution of copper sulfate are applied and rubbed onto the cleaned surface. If the steel is coated with a layer of red copper, the alloy is not corrosion resistant. If no changes have occurred on the surface of the material, then this is stainless steel.

It is impossible to check at home whether steel belongs to the group of food alloys.

The magnetic properties of stainless steel do not in any way affect the performance characteristics, in particular, the corrosion resistance of the material.

Having received the necessary information, you can select the hardware and stainless steel fasteners you need in our store: http://lednik.com.ua/shop

Source: https://lednik.com.ua/articles/492/

Is stainless steel magnetic?

Among the main properties of a metal, the degree of magnetism is distinguished. Recently, there is simply a huge number of stainless steels, the performance characteristics of which can differ significantly. In many ways, the property under consideration depends on the chemical composition of the alloy. It is quite difficult to independently check the degree of magnetism, since it can vary depending on operating conditions.

Is stainless steel magnetic?

What determine the magnetic properties of materials?

To determine the magnetic properties of stainless steel and other alloys, a certain formula is used, which reflects the proportionality coefficient and magnetic susceptibility. Depending on the type of factor used, stainless steel falls into one of several groups:

1. When the coefficient is above zero, the material belongs to the group of paramagnets.
2. When using zero, stainless steel is diamagnetic.
3. Ferromagnets are characterized by good magnetic susceptibility. This group includes nickel, cadmium and iron.

Magnetic properties of stainless steel

Stainless steel becomes magnetic when exposed to a certain field. Such a reaction is associated with the structural features of the alloy, and to some extent, with the chemical composition. Some substances are characterized by reacting to the influence of a magnet.

Stainless steels with good magnetic properties

The magnetic properties of stainless steel largely depend on the structure of the material. They manifest themselves most in the following cases:

1. Martensite is characterized by good magnetic properties and is ferrimagnetic in its pure form. This kind of stainless steel is extremely rare, since it is quite difficult to maintain a pure chemical composition. Like conventional carbon versions, this one can be improved by hardening or tempering. This metal is widely used not only in industry, but also in everyday life. The most widely used brands are: 20X13 and 40X13. They can be subjected to mechanical action, grinding or polishing, as well as various heat treatments. Features of the chemical composition include an increased concentration of chromium and carbon. 20Х17Н2 is another stainless steel, which is characterized by a high concentration of chromium. Due to this, the structure becomes more resistant to moisture and some aggressive agents. Despite the large number of alloying elements, spain is weldable and can be hot or cold forged.
2. Ferrite, depending on the degree of heating, can take two forms: ferromagnetic and paramagnetic. The chemical composition of such materials contains less carbon, making them softer and easier to process. This group includes stainless steel 08Х13, which is actively used in the food industry. In addition, this group includes AISI 430, which is used in food production plants.
3. Martensitic-ferritic alloys are characterized by very attractive performance properties. Alloy 12X13 has a similar structure. Like previous metals, this one can be subjected to mechanical and thermochemical processing.

Steel 20Х13Steel 40Х13

The above information indicates that the martensitic structure has the most pronounced magnetic properties.

When choosing an alloy, it should be taken into account that not all stainless steels are resistant to mechanical damage. Even minor impacts can damage the surface layer. Despite the fact that the chromium film can be restored upon contact with oxygen, new alloys have been produced that are characterized by increased mechanical stability.

Another classification of metals involves their division into the following groups:

1. Highly resistant to acids.
2. Heat-resistant version
3. Food grade stainless steel.

Heat resistant stainless steel

Material marking is carried out using alphanumeric designations. Each symbol is used to designate a specific chemical element, the number indicates the concentration. Other countries have their own specific standards for naming metal.

Non-magnetic stainless steels

There are quite a large number of metals that do not have magnetic properties. They contain nickel and manganese. The following groups of alloys are distinguished:

1. Austenites are the most widely used. This group includes 08Х18Н10 and 10Х17Н13М2Т. These metals are actively used in the manufacture of various products in the food industry, for example, cutlery and dishes. Increased corrosion properties are maintained in almost any operating environment.
2. Austenitic-ferritic stainless steels 08Х22Н6Т and 08Х21Н6М2Т are characterized by an increased concentration of chromium and some other alloying elements. To change the basic characteristics, other chemical elements are also included in the composition.

Steel 10Х17Н13М2ТSteel 08Х18Н10

Non-magnetic stainless steel is selected when the resulting product should not respond to the influence of a magnetic field.

The choice of stainless steel can be made not only taking into account the degree of magnetism, but also the following points:

1. Weldability. Some versions need to be preheated, others weld well even when cold.
2. Ductility is taken into account when choosing a material for cold and hot stamping. A sufficiently high ductility index determines that it is possible to stamp metal sheets in a cold state.
3. Corrosion resistance when exposed to high temperatures. Many metals lose their characteristics when exposed to strong heat, including corrosion resistance.
4. Price is also an important factor. Metals can have high performance characteristics, but due to their high cost, their use for the production of some products is impractical.
5. Degree of machinability. Often, workpieces are supplied for cutting on special equipment. Due to the high concentration of carbon, hardness increases and the surface treatment process becomes more complicated.
6. Heat resistance is also an important quality that is considered when choosing a material. With good heat resistance, the manufactured product does not lose its strength and hardness when exposed to high temperatures.

Some brands are subjected to heat treatment, which increases the strength and hardness of the surface.

When tempering is carried out, the structure becomes more plastic and resistant to variable loads.

How to determine whether magnetic or non-magnetic steel is stainless?

As previously noted, it is possible to determine whether stainless steel is magnetic without the use of special equipment. Among the features of the procedure, we note the following points:

1. The test area should be polished to a high shine. Hand tools and special materials can be used for this.
2. A few drops of concentrated copper sulfate are applied to the cleaned area.
3. If the metal is stainless steel, then a red coating will appear on the surface.

Determination of magnetic properties using vitriol

This process allows you to determine which stainless steel is magnetic and which is not corrosion resistant. It is almost impossible to determine the characteristics of a food alloy on your own.

Magnetic properties can also be checked using a regular magnet. However, it does not give an accurate result.

That is why it is recommended to purchase products from reputable manufacturers.

Portable metal analyzer

In conclusion, we note that magnetic properties do not in any way reduce the corrosion resistance of the surface. That is why such alloys are characterized by a wide range of applications.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/magnititsya-li-nerzhaveika.html

What metals are magnetic?

Only steels have magnetic properties , and not all of them. For example, austenitic stainless steels do not attract magnets because they do not have ferromagnetic properties. However, there are a sufficient number of enthusiasts who believe that magnetic waves are emitted by any metal, and therefore there should be a search magnet for gold and silver, and for some this expression is quite normal for perception and practical use.

ATTENTION! MAGNETS FOR SEARCHING GOLD, COPPER, SILVER DO NOT EXIST!

THEY SIMPLY ARE NOT - ANYWHERE!

In our article we describe the theory of how non-ferrous and precious metals can be detected using magnetic fields. This article is our fantasy, supported by scientific developments of foreign scientists.

See also the article - Extraction of scrap metal from water (about ferrous metal and search magnet).

Device for adjusting the magnetic field from metal objects

Strictly speaking, this is not a magnet, but rather an electromagnet, with the help of which you can initiate and configure any magnetic radiation, even quite weak ones, to be captured by appropriate devices. It is not easy to build such a device, but the authors, citizens of Australia, have no doubt about its effectiveness.

That's why they patented their invention in their patent office. Based on the fact that Australian soil is not much different from domestic soil, we will give a description of the device and operating principle of such a magnet for gold and silver.

Although it is necessary to repeat - in the generally accepted sense, this design has nothing .

The operation of the device is based on the well-known physical fact that when any object that generates magnetic oscillations in an alternating electric field moves, changes occur inside the trapper circuit associated with the movement of atoms around the nucleus.

If the area of ​​electric field generation is sequentially moved along or across the magnetic field from a metal object, changes will occur in this area, the intensity of which determines the degree and strength of the interaction of two fields - magnetic and electric.

The difficulty is that strong magnetic fields are not created by noble metals . It is known, for example, that, according to the principle of decreasing, the electrochemical potentials of non-ferrous metals are located as follows (we consider only the area of ​​interest to us): copper → mercury → silver → palladium → platinum → gold.

Thus, if the expression “is copper attracted to a magnet” may still have some basis, then the phrase “magnet for gold” does not make any sense at all.

It is more correct to talk about an electromagnetic trap, which will record the fact of a coordinated change in electric and magnetic fields in a certain, rather local, metallic volume.

— how copper interacts with a magnet:

Recording of changes that occur in the apparatus under the influence of such fields is captured by the measuring circuit. It is a highly sensitive spring made of rhenium, a rare metal that is absolutely insensitive to temperature changes. The rhenium spring must be adjusted to operate.

  The process is to set the conditional zero of the device, for which it is placed as far as possible from all metal objects. In urban areas, such a “search magnet for gold, silver and other precious metals” will not work. However, search engines are much more likely to look for gold, platinum, copper, silver, etc.

in old abandoned rural estates

With any movement of the device, a similar action occurs with the electric field, while the magnetic field remains constant in coordinates. Therefore, the resulting movement of the spring will also be different.

Where it turns out to be most intense, its source is almost certainly located - the magnetic field. Another thing is that this kind of search magnet for non-ferrous metals will not be able to show which metal is hidden under the thickness of wood or earth.

But the device will definitely show that there is metal there.

Any metal can be detected by a magnetic field

The principle of operation of such a pseudo-magnet is similar to the coils of a metal detector, with the only difference being that the “magnet” will be tuned to only 1 metal and this is in theory - but we don’t know how it will behave in practice, BUT, most likely, it’s cheaper, faster and simpler will use an ordinary metal detector to search for non-ferrous metals, since not a single wizard has yet invented a magnet for non-ferrous and precious metals, maybe because there are no wizards!

How to assemble and set up

It will be very difficult to find/buy a rhenium spring, but all other parts of the device are quite accessible for making yourself. The sequence is:

1. A steel axle is made from a thin-walled steel pipe with a diameter of no more than 16 mm. Its length should not be less than three diameters, otherwise the change in the magnetic field cannot be detected.
2. A frame is made from thin copper or brass wire. The authors do not describe its dimensions, but, based on the dimensions of the tubular axis, it should be at least 200x200 mm. The frame must be sufficiently rigid.
3. Three (as many as possible) holes are drilled in the tubular axle at equal distances, in which the wooden axles are placed.
4. Thin-walled wooden disks are made, the number of which must correspond to the number of holes drilled in the axle. Obviously, discs can also be made of plywood: what matters is the mass of the disc and its absolute immunity to magnetic fields.
5. The central sectors of each disk are covered with metal foil made of the metal that will be searched. Thus, a search magnet for non-ferrous metals - copper, gold and silver (platinum is searched for much less frequently) should have three sets of replaceable wooden disks.
6. The frame with disks must be able to move freely along the entire tubular axis with fixation in a certain place. If the fits of the mating parts are made with the required accuracy, then there should be no swaying of the frame when it moves.
7. To create a magnetic trap, plates from an old transformer are used, which are packed into the frame outline. The distance between adjacent plates should not exceed 1.5 mm in thickness and 56 mm in length. Such plates form the screen of the device that perceives magnetic radiation.
8. Next, assemble the magnetic coil. You will need a solenoid made of 600 layers of enameled wire, which is connected to an alternating current voltage source. The winding should be multilayer, this will reduce the parasitic capacitance of the coil and make the device less inertial.
9. A ferromagnetic or - which is better - a ferroelectric core is inserted inside the coil.
10. By connecting this structure through a step-down transformer, a constant position of the frame with the plates is achieved relative to the wooden disks. This will be the conditional zero of the search “magnet” for non-ferrous metals.

The easiest way to check whether a search “magnet” attracts gold and silver is on a real object made of these metals. At the same time, it will be possible to establish the practical sensitivity of the device.

about how a search magnet does NOT magnetize gold, silver and other coins

Source: https://respect-kovka.com/kakie-metally-magnityatsya/

Why does a magnet attract or everything about magnetic fields

 Why does a magnet attract or everything about magnetic fields

Magnets, like the toys stuck to your refrigerator at home or the horseshoes you were shown in school, have several unusual features. First of all, magnets are attracted to iron and steel objects, such as the door of a refrigerator. In addition, they have poles. Bring two magnets closer to each other. The south pole of one magnet will be attracted to the north pole of the other.

The north pole of one magnet repels the north pole of the other. The magnetic field is generated by electric current, that is, by moving electrons. Electrons moving around an atomic nucleus carry a negative charge. The directed movement of charges from one place to another is called electric current. An electric current creates a magnetic field around itself.

This field, with its lines of force, like a loop, covers the path of electric current, like an arch that stands over the road. For example, when a table lamp is turned on and a current flows through the copper wires, that is, the electrons in the wire jump from atom to atom and a weak magnetic field is created around the wire.

In high-voltage transmission lines, the current is much stronger than in a table lamp, so a very strong magnetic field is formed around the wires of such lines. Thus, electricity and magnetism are two sides of the same coin - electromagnetism.

The movement of electrons within each atom creates a tiny magnetic field around it. An electron moving in orbit forms a vortex-like magnetic field. But most of the magnetic field is created not by the movement of the electron in orbit around the nucleus, but by the movement of the atom around its axis, the so-called spin of the electron. Spin characterizes the rotation of an electron around an axis, like the movement of a planet around its axis.

In most materials, such as plastics, the magnetic fields of individual atoms are randomly oriented and cancel each other out. But in materials like iron, the atoms can be oriented so that their magnetic fields add up, so a piece of steel becomes magnetized. Atoms in materials are connected in groups called magnetic domains. The magnetic fields of one individual domain are oriented in one direction.

That is, each domain is a small magnet. Different domains are oriented in a wide variety of directions, that is, randomly, and cancel each other's magnetic fields. Therefore, a steel strip is not a magnet. But if you manage to orient the domains in one direction so that the forces of the magnetic fields combine, then beware! The steel strip will become a powerful magnet and will attract any iron object from a nail to a refrigerator.

Magnetic iron ore mineral is a natural magnet. But still, most magnets are made artificially. What force can force atoms to line up to form one large domain? Place the steel strip in a strong magnetic field. Gradually, one by one, all domains will turn in the direction of the applied magnetic field.

As the domains rotate, they will draw other atoms into this movement, increasing in size, literally swelling. Then the identically oriented domains will connect, and lo and behold, the steel strip has turned into a magnet. You can demonstrate this to your comrades using an ordinary steel nail. Place the nail in the magnetic field of a large neodymium magnet.

Hold it there for a few minutes until the nail domains line up in the desired direction. Once this happens, the nail will briefly become a magnet. With its help you can even pick up fallen pins from the floor.

Why doesn't a magnet attract everything?

In fact, the interaction of a magnet with substances has many more options than just “attracts” or “does not attract.” Iron, nickel, and some alloys are metals that, due to their specific structure, are very strongly attracted by a magnet.

The vast majority of other metals, as well as other substances, also interact with magnetic fields - they are attracted or repelled by magnets, but only thousands and millions of times weaker.

Therefore, in order to notice the attraction of such substances to a magnet, you need to use an extremely strong magnetic field, which you cannot get at home.

But since all substances are attracted to a magnet, the original question can be reformulated as follows: “Why then is iron so strongly attracted by a magnet that manifestations of this are easy to notice in everyday life?” The answer is: it is determined by the structure and bonding of iron atoms. Any substance is composed of atoms connected to each other by their outer electron shells.

It is the electrons of the outer shells that are sensitive to the magnetic field; they determine the magnetism of materials. In most substances, the electrons of neighboring atoms feel the magnetic field “at random” - some repel, others attract, and some generally try to turn the object around.

Therefore, if you take a large piece of a substance, then its average force of interaction with a magnet will be very small.

Iron and metals similar to it have a special feature - the connection between neighboring atoms is such that they sense the magnetic field in a coordinated manner. If a few atoms are tuned to be attracted to a magnet, they will cause all neighboring atoms to do the same. As a result, in a piece of iron all the atoms “want to attract” or “want to repel” at once, and because of this, a very large force of interaction with the magnet is obtained.

A magnet is a body that has its own magnetic field. In a magnetic field, there is some effect on external objects that are nearby, the most obvious being the ability of a magnet to attract metal.  

The magnet and its properties were known to both the ancient Greeks and the Chinese. They noticed a strange phenomenon: small pieces of iron were attracted to some natural stones.

This phenomenon was first called divine and used in rituals, but with the development of natural science it became obvious that the properties were of a completely earthly nature, which was first explained by the physicist from Copenhagen Hans Christian Oersted.

He discovered in 1820 a certain connection between the electric discharge of current and a magnet, which gave rise to the doctrine of electric current and magnetic attraction.

Natural science research

Oersted, conducting experiments with a magnetic needle and a conductor, noticed the following feature: a discharge of energy directed towards the needle instantly acted on it, and it began to deviate.

The arrow always deviated, no matter from which side he approached.

A physicist from France, Dominique François Arago, began repeated experiments with a magnet, using as a basis a glass tube rewound with a metal thread, and he installed an iron rod in the middle of this object.

With the help of electricity, the iron inside began to be sharply magnetized, because of this various keys began to stick, but as soon as the discharge was turned off, the keys immediately fell to the floor.

Based on what was happening, a physicist from France, Andre Ampere, developed an accurate description of everything that happened in this experiment.

When a magnet attracts metal objects to itself, it seems like magic, but in reality the “magical” properties of magnets are associated only with the special organization of their electronic structure. Because an electron orbiting an atom creates a magnetic field, all atoms are small magnets; however, in most substances the disordered magnetic effects of atoms cancel each other out.

The situation is different in magnets, the atomic magnetic fields of which are arranged in ordered regions called domains. Each such region has a north and south pole. The direction and intensity of the magnetic field is characterized by the so-called lines of force (shown in green in the figure), which leave the north pole of the magnet and enter the south.

The denser the lines of force, the more concentrated the magnetism. The north pole of one magnet attracts the south pole of another, while two like poles repel each other. Magnets attract only certain metals, mainly iron, nickel and cobalt, called ferromagnets.

Although ferromagnetic materials are not natural magnets, their atoms rearrange themselves in the presence of a magnet in such a way that the ferromagnetic bodies develop magnetic poles.

Magnetic chain

Touching the end of a magnet to metal paper clips creates a north and south pole for each paper clip. These poles are oriented in the same direction as the magnet. Each paper clip became a magnet.

Countless little magnets

Some metals have a crystalline structure made up of atoms grouped into magnetic domains. The magnetic poles of the domains usually have different directions (red arrows) and do not have a net magnetic effect.

Formation of a permanent magnet

Typically, iron's magnetic domains are randomly oriented (pink arrows), and the metal's natural magnetism does not appear. If you bring a magnet (pink bar) closer to the iron, the magnetic domains of the iron begin to line up along the magnetic field (green lines). Most of the magnetic domains of iron quickly align along the magnetic field lines. As a result, the iron itself becomes a permanent magnet.

Magnetic effect

Today it is obvious that the matter is not in miracles, but in a more than unique characteristic of the internal structure of the electronic circuits that form magnets. An electron that constantly rotates around an atom forms the same magnetic field.

Microatoms have a magnetic effect and are in complete equilibrium, but magnets, with their attraction, influence some types of metals, such as iron, nickel, cobalt.
These metals are also called ferromagnets. In close proximity to a magnet, atoms immediately begin to rearrange and form magnetic poles.

Atomic magnetic fields exist in an ordered system; they are also called domains. In this characteristic system there are two poles opposite to each other - north and south.

Application

The north pole of a magnet attracts the south pole, but two identical poles immediately repel each other.

Modern life without magnetic elements is impossible, because they are found in almost all technical devices, including computers, televisions, microphones, and much more. In medicine, magnets are widely used in examinations of internal organs and in magnetic therapy.

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The material uses photos and excerpts from:

http://information-technology.ru/sci-pop-articles/23-physics/231-pochemu-magnit-prityagivaet-zhelezo

http://www.kakprosto.ru/kak-821401-pochemu-magnit-prityagivaet-zhelezo

http://www.voprosy-kak-i-pochemu.ru/pochemu-magnit-prityagivaet-ili-vse-o-magnitnyx-polyax/

http://log-in.ru/articles/pochemu-magnit-ne-vse-prityagivaet/

Source: https://magnet-prof.ru/index.php/pochemu-magnit-prityagivaet-ili-vse-o-magnitnyih-polyah.html