RU2136068C1 - Magnetic material for permanent magnets and method for its manufacturing - Google Patents

Abstract

FIELD: powder metallurgy, in particular, materials with specific physical characteristics. SUBSTANCE: magnetic material contains Fe-B-Co-R, where R is sum of R1 and R2; R1 is at least one of rare-earth elements from group of neodymium (Nd), praseodymium (Pr), and R2 is at least one of rare-earth elements from group of dysprosium (Dy), terbium (Tb). Addition M is sum of M1 and M2; M1 is at least one of elements from group of aluminum (Al), niobium (Nb), chromium (Cr), gallium (Ga), and M2 is at least one of elements from group of titan (Ti), hafnium (Hf), zirconium (Zr), vanadium (V), tantalum (Ta), scandium (Sc) and uranium (U) of the following isotope composition: 99.28-99.9999 of U238, 0.0001-0.72 of U235. Method for manufacturing of magnetic material involves grinding base alloy and addition alloy, mixing alloys, pressing powder mix in magnetic field, baking article and its cooling. EFFECT: increased coercive force of magnets, increased anisotropy of magnetic characteristics and increased good-to-bad output ratio for relatively low power consumption. 11 cl, 5 dwg, 3 tbl, 4 ex

Description

 The present invention relates to the field of powder metallurgy, in particular, special materials with special physical properties, and more particularly, to a magnetic material for permanent magnets and a method for its manufacture.

 The currently known and widely used magnetic materials of the Fe-B-R and Fe-B-Co-R systems with high magnetic energy (BH / 2) max are widely used in electric motors, generators, magnetic couplings, etc. These materials are used in various types of household appliances - audio and video equipment, peripheral devices of electronic computers (computers), mixers, coffee grinders, hair dryers, vacuum cleaners, refrigerators, etc.

 However, the relatively low values of the coercive force iHc of the above materials somewhat limit their scope. It is known that with increasing material temperature for a permanent magnet, its coercive force iHc decreases, and the permanent magnet can be fully demagnetized by holding it at elevated temperature. If its coercive force iHc at room temperature is relatively large, such a demagnetizing effect by temperature will be negligible.

 In addition, increasing the value of the coercive force iHc of the material for permanent magnets makes it possible to reduce the thickness of the permanent magnet while maintaining the specified technical characteristics of the product. Therefore, increasing the iHc of materials for permanent magnets and reducing the specific energy consumption for the manufacture of magnets is an urgent task at the present time.

 In the manufacture of permanent magnets from known materials of the Fe-B-R and Fe-B-Co-R systems, the specific energy consumption is relatively high.

Known magnetic material (patent EP N 0134305 B) of the Fe-BR system. In the known material, R is the sum of R ₁ and R ₂ , wherein R ₁ is at least one of the rare earth elements selected from the group: neodymium (Nd), praseodymium (Pr), and R ₂ is at least one of the rare earth elements selected from the group of dysprosium (Dy), terbium (Tb), gadolinium (Gd), holmium (Ho), erbium (Er), thulium (Tm) and ytterbium (Yb). Known material includes additive M, which is at least one of the elements selected from the group of chromium (Cr), tantalum (Ta), niobium (Nb), aluminum (Al), vanadium (V), tungsten (W), molybdenum (Mo).

In the known material, the above elements are contained in the following ratio (at.%): 0.05-5% R ₁ , 12.5-20% R ₂ 4 - 20% B and the rest of the iron (Fe) with the addition of M no more than 9% .

It is well known that the material properties for permanent magnets of the Fe-BR system are determined by the number and size of grains, the specific magnetization and coercive force of the main phase (R) ₂ Fe ₁₄ B, as well as the number, structure and composition of the phases that insulate the grains of the main phase (R) ₂ Fe ₁₄ V.

To obtain maximum characteristics of a magnetic material, for example (BH) max, operating temperature (Tmo), it is necessary that the main phase (R) ₂ Fe ₁₄ V be present in the material in an amount approaching 100%, have an optimal grain size and the maximum possible values specific magnetization and coercive force, and the phases that isolate the grains of the main phase (R) ₂ Fe ₁₄ V from each other should be present in a minimal amount along the grain boundaries of the main phase and be weakly magnetic or non-magnetic.

Due to the fact that the main mechanism of the coercive force of the magnetic material of the R-Fe-B system is the destruction of reverse magnetization domains, the reason for the facilitated appearance of reverse magnetization domains can be:
1) a relatively low magnetocrystalline anisotropy or a defective structure (high density of lattice defects, inclusions, etc.) of the main phase of the type R ₂ Fe ₁₄ V, which facilitates the nucleation of reverse magnetization domains inside the grains of the main phase;
2) insufficient insulating properties of the intergranular phase (s), facilitating the nucleation of reverse magnetization domains at the interface between the main and intergranular phase (s);
3) poor morphology and / or insufficient amount of intergranular phase (s), which worsens the isolation of the grains of the main phase and facilitates the penetration of reverse magnetization domains on one grain into another.

The presence of heavy rare earth elements in the known material, such as dysprosium (Dy), terbium (Tb), gadolinium (Gd), holmium (Ho), etc., to a greater or lesser extent leads to an increase in the anisotropy field H _{A of the} main phase R ₂ Fe ₁₄ V magnetic material, which leads to an increase in the coercive force iHc. However, the exchange interaction between the ions of heavy rare-earth elements and iron leads to an antiferromagnetic orientation of their magnetic moments, which causes a significant decrease in the specific magnetization and thereby the residual induction Br and (BH) max. In order to increase the residual induction of Br, Cr, Al, Nb, etc., which are magnetoneutral, are additionally introduced into the magnetic material, while the content of dysprosium and terbium is reduced in the material, which, in addition, increase the cost of the magnet. The main mechanism of the influence of the additional elements mentioned above on the coercive force is the formation of weakly magnetic neodymium-enriched phases that isolate the grains of the main phase from each other. Some of these elements, for example Al, improve the wettability of the grains of the main phase Nd ₂ Fe ₁₄ B by the liquid phase, which accelerates the sintering process when obtaining magnetic material. Since the grain size of the main phase of the magnetic material is inhomogeneous, namely, varies between 0.3-80 μk, the material has a relatively low coercive force iHc.

Based on the foregoing, this material has relatively low magnetic properties, namely:
iHc coercive force - 5-20 KOe (398-1520 kA / m);
energy product (BH) max - 5-38.4 MGOe (39.8-305.7 kJ / m ³ );
residual induction Br - 5-12 KG (0.5-1.2 T).

At the same time, large values of (BH) max correspond to low values of the coercive force iHc, and, conversely, lower values of iHc correspond to large values of (BH) max. With an optimal ratio of components in a known magnetic material, the coercive force iHc is at least 10 KOe (796 kA / m), (BH) max is at least 20 MGOe (159.2 kJ / m ³ ) and the residual induction Br is at least 9 KG (0, 9 T). In the known material there is a sharp decrease in magnetic properties at temperatures above 80-100 ^o C, since it has a low Curie temperature Tc - 310 ^o C. This limits its use in electric machines with high specific power. Known material also has a relatively high energy consumption in its manufacture due to the high strength of the ingot and the relatively high sintering temperature.

Known magnetic material of the system Fe-B-Co-R (patent EP N 0106948 B) with a higher Curie temperature. In the known material, R is the sum of R ₁ and R ₂ , wherein R ₁ is at least one of the rare earths selected from the group of neodymium (Nd), praseodymium (Pr), and R ₂ is at least one from heavy rare earths. Known material also includes an additive M, which is the sum of M ₁ and M ₂ , wherein M ₁ is at least one of the elements selected from the group aluminum (Al), niobium (Nb), chromium (Cr) and others, and M ₂ is at least one of the elements selected from the group of titanium (Ti), hafnium (Hf), zirconium (Zr), vanadium (V), tantalum (Ta), etc. These components are contained in the magnetic material in the following ratio, at.%: 8-30% R - R ₁ + R ₂ ; 2-28% B, not more than 50% Co and the rest is iron (Fe) with additives M - M ₁ + M ₂ , where there are no more than 12.5%.

The presence of cobalt (Co) in a magnetic material increases its Curie temperature (Tc), it reaches 750 ^o C. This allows you to use the known material without significantly reducing its magnetic properties at temperatures of 120-160 ^o C. However, the high content of cobalt (Co) in the material leads to the appearance of a soft magnetic phase enriched in cobalt, which is the reason for a sharp decrease in the coercive force iHc. To compensate for the decrease in the coercive force iHc, the alloy is alloyed with an increased amount of rare-earth elements and boron (B), which in turn leads to a decrease in (BH) max. The latter is explained by a relative decrease in the amount of the main phase Nd ₂ Fe ₁₄ B. In the known magnetic material, the average grain size of the main phase has a range of 1-100 μk, which leads to a low coercive force iHc. In addition, the known material is distinguished by its relatively low processability, associated mainly with the relatively high strength of the ingot and the sintering temperature, which leads to high specific energy consumption during grinding of the ingot and sintering.

Closest to the present invention in technical essence and the achieved result is magnetic material (patent EP 0539592, published 05-05.93), including Fe-B-Co-R, where R is the sum of R ₁ and R ₂ , and R ₁ is, at least one of the rare earths selected from the group of neodymium (Nd) and praseodymium (Pr), and R ₂ is at least one of the rare earths selected from the group of dysprosium (Dy) and terbium (Tb), and additive M, which is the sum of M ₁ and M ₂ , and M ₁ is at least one of the elements selected from the group aluminum (Al), niobium (Nb), chromium (Cr), and M ₂ is at least one of the elements selected from the group titanium (Ti), hafnium (Hf), zirconium (Zr), vanadium (V), tantalum (Ta), and contains uranium (U) in the following ratio of components, at.%:
at least one of the rare earths selected from the group:
neodymium and praseodymium - 12.0-17.0;
at least one of the rare earths selected from the group:
dysprosium and terbium - 0.1-5.0;
at least one of the elements selected from the group:
aluminum, niobium, chromium - 0.5-4.0;
at least one of the elements selected from the group:
titanium, hafnium, zirconium, vanadium, tantalum - 0.1-1.5;
cobalt - 2.0-6.0
boron - 6.5-8.5
uranium - 0.05-1.5
iron is the rest.

It is necessary that uranium (U) have the following isotopic composition, at.%:
uranium 238 - 99.7 - 99.9999
uranium 235 - 0.0001 - 0.3
In the magnetic material, the additive M ₁ may also contain gallium, and the additive M ₂ may contain scandium.

 Such magnetic material can be obtained by the following well-known method.

 A mixture is prepared containing the above components in the indicated ratio and loaded into a melting furnace.

In a vacuum induction furnace in an argon atmosphere at a pressure of 300 mm RT. Art. get a melt, the composition of which corresponds to the composition of the magnetic material. Then the resulting melt is poured into a water-cooled copper mold and an ingot is obtained. The latter is subjected to coarse grinding to a particle size of less than 500 μk, and then to fine grinding in a vibratory ball mill to a particle size of 1-5 μk. The resulting powder is placed in a magnetic field with a strength of 10 kOe to create a magnetic texture and is pressed with a force of 0.1 - 5 t / cm ² . Then the pressed billet is subjected to sintering at a temperature of 1000 - 1200 ^o C and heat treatment at a temperature of 400 - 1000 ^o C.

 Such a magnetic material has high magnetic properties, namely, it has an increased value of the coercive force iHc of about 25 kOe at (BH) max 29-36 MGOe and specific energy consumption of 0.71-0.9.

 However, this well-known magnetic material made in a well-known manner is not free from disadvantages.

First, in the preparation of the initial alloy by smelting, the alloying elements are U, Ga, Sc, Al, Tl, Dy, etc. are distributed in phases R ₂ Fe ₁₄ B, R ₄ Fe ₄ B and others. uncontrollably, in accordance with the nonequilibrium phase state diagram, as a result of which the phase composition and structure of the magnetic material are not optimal. Such alloying is especially ineffective in the case of low contents of alloying elements.

 Therefore, in order to get the right element in the right place in the right amount, you have to introduce it into the charge in excess, which can be harmful from the point of view of consumer properties of magnets, for example, reduce magnetic induction.

 Secondly, the known method for producing magnetic material cannot ensure the manufacture of magnets with the required composition accuracy for all components of a complex alloyed alloy. In this regard, the technologist is forced to use the alloy that metallurgists produce with the existing variation in composition and, accordingly, obtain finished magnetically hard material with a similar variation in composition and properties, which significantly reduces the yield of suitable magnets.

 Thirdly, uncontrolled external factors (temperature, humidity, etc.) lead to a change in the composition of the material during its manufacture. This prevents the desired combination of material properties from being obtained in the final product.

Also widely used is a magnetic material based on the SmCo ₅ intermetallic compound (US Pat. No. 3,655,464), containing components in the following ratio (%):
rare earth metal (samarium, cerium mischmetal) - 32 - 36
cobalt is the rest.

This well-known magnetic material has a high operating temperature due to the high Curie temperature (≈ 700 ^o C) of the main SmCo ₅ phase. However, this material has a relatively low energy product (BH) max = 20-24 MG · E and a high cost.

The specified magnetic material is obtained by the method (US patent N 3.655.464), containing the following operations:
- smelting of the main alloy containing (wt.%)
rare earth metal (samarium, cerium mischmetal) - 32 - 36,
cobalt - the rest;
- smelting alloy additives containing (wt.%)
rare earth metal - 46-65
cobalt - the rest;
- crushing and grinding ingots of the main alloy and alloy additives to obtain alloy powders with a particle size of a powder of from about 1 to 10 microns:
- mixing the obtained powders of the main alloy and alloy additives in a ratio that ensures the receipt of the material of a given composition;
- orientation of the obtained mixture of powders of the main alloy and alloy additive in a magnetic field with a strength of from about 7 to about 15 kOe and pressing with a pressure of from about 5 to about 10 t / cm ² ;
- isothermal sintering in the temperature range from about 950 ^o C to about 1200 ^o C to a density of sintered preform of at least about 80% and cooling.

The manufacture of a magnetic material based on the Nd ₂ Fe ₁₄ B intermetallic compound as described above results in the production of magnets with low properties and yield.

 Firstly, the use of an additive alloy enriched in a rare-earth metal with respect to the base alloy, although it allows to adjust the composition of the final material by mixing them, but only for one element - rare-earth. However, the content of the remaining components of the known magnetic material, which have a significant effect on the magnetic properties, is formed only during the smelting process and cannot be changed during the manufacturing process of the material. It should be noted that the same drawback is inherent in traditional, well-known technology. Smelting an alloy, especially a multicomponent one, can provide an accuracy of "getting" into a given composition from about ± 0.1% to ± 0.5%, depending on the physicochemical properties of the alloying element. To ensure high magnetic properties and yield of suitable magnets, it is necessary that the content of vital elements in the material is set with an accuracy of ± 0.05 to 0.1% and is maintained (or controlled to a predetermined value) throughout the entire process. In the case when the content of alloying elements in a magnetic material should be about 0.01-0.001%, the manufacture of its predetermined composition by smelting does not guarantee this.

 Secondly, sintering at a constant temperature leads to the fact that only part of the magnets in one cage (or only part of the volume of large-sized magnets) is the optimal time at the optimum temperature, which does not allow to obtain a high yield of magnets in terms of properties and uniformity of magnetic properties .

 This phenomenon is associated with the following. There is a natural dispersion of powder particles in size and composition. In addition, the press blanks are also heterogeneous in density, especially large ones, and any sintering furnace is characterized by a certain temperature gradient. Therefore, when isothermal sintering is carried out, only part of the volume of the billet or only part of the volume of the cage in the furnace is the optimal time at the optimum temperature and reach a given density and level of magnetic properties. The remaining parts of large magnets or other magnets in the cage of optimal density and properties do not reach or, conversely, pass them. This determines a relatively low level of magnetic properties and their uniformity.

Disclosure of Invention
The basis of the invention is the task of creating a magnetic material of such a chemical composition and with such a component content that, while maintaining high values of the coercive force iHc, would have a wider field of application - medicine and some types of household appliances that are in prolonged contact with the human body.

The basis of the invention is also the task of creating such a method of manufacturing a magnetic material that would allow the use of an additive alloy and special heat treatment to obtain magnets with a high coercive force, achieved by optimizing the structure of phases that isolate the grains of the main phase Nd ₂ Fe ₁₄ B from each other ; with high uniformity of magnetic properties and yield at relatively low specific energy consumption.

The problem is solved in that in a magnetic material containing Fe-B-Co-R, where R is the sum of R ₁ and R ₂ , and R ₁ is at least one of the rare earth elements selected from the group of neodymium (Nd ) and praseodymium (Pr), a R ₂ is at least one of the rare-earth elements selected from the group of dysprosium (Dy) and terbium (Tb), and additive M, which is the sum of M ₁ and M ₂ and M ₁ is at least one element selected from the group of aluminum (Al), niobium (Nb), chromium (Cr), and M ₂ is at least one of the elements, selected from the group titanium (Ti), hafnium (Hf), zirconium (Zr), vanadium (V), tantalum (Ta), scandium (Sc) and uranium (U) of the following isotopic composition, at.%: uranium 338 - 99, 28 - 99.9999: uranium 235 - 0.0001-0.72, according to the invention, the components are contained in the following ratio, at.%:
at least one of the rare earths selected from the group:
neodymium and praseodymium - 12.0-17.0;
at least one of the rare earths selected from the group:
dysprosium and terbium - 0.1-5.0:
at least one of the elements selected from the group:
aluminum, niobium, chromium, gallium - 0.5-4.0;
at least one of the elements selected from the group:
titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.1-1.5;
boron - 6.5-8.5
cobalt - 0.1-1.5
uranium - 0.001-0.025
iron is the rest.

Such a magnetic material, according to the invention, has high magnetic properties, in particular, has an increased value of the coercive force iHc of more than 25 kOe (1990 kA / m) at (BH) max at 29-36 MG · E (230.8-286.6 kJ / m ³ ).

It is well known that the material properties for permanent magnets of the Fe-BR system are determined by the number and size of grains, the specific magnetization and coercive force of the main phase (R) ₂ , Fe ₁₄ B, as well as the number, structure and composition of the phases that insulate the grains of the main phase (R) ₂ Fe ₁₄ V.

To obtain maximum characteristics of a magnetic material, for example (BH) max operating temperature (Tmo), it is necessary that the main phase (R) ₂ Fe ₁₄ B be present in the material in an amount approaching 100%, have an optimal grain size and the maximum possible specific magnetization and coercive force, and the phases that isolate the grains of the main phase (R) ₂ Fe ₁₄ B from each other should be present in a minimal amount along the grain boundaries of the main phase and be weakly magnetic or non-magnetic.

Due to the fact that the main mechanism of the coercive force of the magnetic material of the R-Fe-B system is the destruction of reverse magnetization domains, the reason for the facilitated appearance of reverse magnetization domains can be:
1) relatively low magnetocrystalline anisotropy or defective structure (high density of lattice defects, inclusions, etc.) of the main phase of the type R ₂ Fe ₁₄ B, which facilitates the nucleation of reverse magnetization domains inside the grains of the main phase;
2) insufficient insulating properties of the intergranular phase (s), facilitating the nucleation of reverse magnetization domains at the interface between the main and intergranular phase (s);
3) poor morphology and / or insufficient amount of intergranular phase (s), which worsens the isolation of the grains of the main phase and facilitates the penetration of reverse magnetization domains from one grain to another.

Studies of magnetic material showed that the uranium introduced into the material is not distributed uniformly: about 80-90% of the introduced uranium is concentrated in phases that isolate the grains of the main phase of the type R ₂ Fe ₁₄ B, and about 10-20% of the introduced uranium dissolves in the grains of the main phase of the type R ₂ Fe ₁₄ B, mainly enriching the grain boundaries of this main phase.

Such behavior of uranium, namely, the enrichment of uranium compounds of the grain boundaries of the main phase as a result of the interaction of the grains of the main phase with a complex uranium-containing eutectic during sintering, improves the magnetic isolation of the grains of the main phase of the type R ₂ Fe ₁₄ B and, therefore, increases the coercive force.

It should also be noted that the partial dissolution of uranium in the main phase of the type R ₂ Fe ₁₄ B leads to a local increase in the anisotropy field of the main phase and, consequently, to an increase in the coercive force.

 It should also be noted that natural uranium containing 238 and 235 isotopes is used in the known magnetic material. When the uranium content in the material is 0.05 at.%, Its specific activity is 90 Vk / g, which is at the level of natural materials, for example, granites having a specific activity of more than 100 Vk / g and widely used in construction. In accordance with IAEA standards, materials with a specific activity of less than 70 Vc / g are non-radioactive. When depleted uranium is used in a known magnetic material, its specific activity will be 70 Vc / g, which corresponds to the IAEA standards.

 When the amount of uranium in the proposed material is in the amount of 0.001-0.025 at.%, Regardless of its isotopic composition (within the claimed range), the specific activity of the magnetic material will be 1-35 Vc / g, which is significantly lower than the IAEA standards and can significantly expand its use, for example, in medicine for implantation and products that are in prolonged contact with living organisms.

 When the cobalt content is up to 0.1-1.5 at.%, The level of induced activity of the material is negligible and the cost is low while maintaining high consumer properties of the material.

Thus, with a minimum content in the magnetic material according to the invention of uranium (U) - 0.001-0.025%, and cobalt (Co) - 0.1-1.5%, it retains high values of the coercive force iHc of more than 25 kOe (2000 kA / m) at (BH) max - 29-36 MG · E (230-290 kJ / m ³ ), which expanded the scope of its application, namely, it allowed the use of living organisms in medicine for implantation into tissues.

The problem is also solved by the fact that in the method of producing magnetic material, which consists in the fact that each of the previously prepared base alloy and alloy additive are crushed to obtain crushed alloys, which are mixed in a ratio that provides a material of a given composition, and get a mixture of crushed alloys , the latter is sent to the grinding zone, where the specified mixture of crushed alloys is crushed to a particle size average particle size of 1-10 μk and a mixture of powders is sent to the pressing zone, in which they create an orienting magnetic field, and the mixture is pressed, resulting in a low-density workpiece, which is sent to the sintering zone to increase the workpiece density, reaching at least 80% of theoretical, and a sintered workpiece is obtained, which is sent to the cooling zone and cooled , according to the invention, the base alloy contains components in the following ratio, at.%:
at least one of the rare earths selected from the group: neodymium and praseodymium - 11 - 17
at least one of the rare earth elements selected from the group: dysprosium and terbium - 0.01 - 0.1
at least one of the elements selected from the group: aluminum, niobium, chromium - 0.01 - 1.5
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum - 0.01 - 1.0
cobalt - 0.01 - 1.4
boron - 4.8 - 8.5
iron - The rest
and alloy - the additive contains components in the following ratio, at.%:
at least one of the rare earth elements selected from the group: neodymium and praseodymium - 25 - 11
at least one of the rare earth elements selected from the group: dysprosium and terbium - 10 - 0.01
at least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 8.0 - 0.01
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 6.0 - 0.01
cobalt - 10.0 - 0.01
boron - 15.0 - 4.8
uranium - 1.5 - 0.002
iron - The rest
in the sintering zone in the heating section, a vacuum of about 10 ^-1 to about 10 ^-6 mm Hg is created. and the low-density preform is heated stepwise with an average heating rate of from about 1 to about 50 ^° C / min to at least 950 ^° C, whereby a heated preform, free of volatiles, is obtained, which is sintered in the sintering section of the specified sintering zone in a temperature range from about 950 ^o C to about 1200 ^o C with an average rate of temperature change of 1-40 ^o C / min, and in the cooling zone, the sintered billet is cooled stepwise with an average cooling rate of 1-200 ^o C / min.

This method of manufacturing a magnetic material allows one to obtain permanent magnets with high magnetic properties - residual induction Br = 11-13 kG (1.1-1.3 T), coercive force of magnetization iHc - up to 26.4 kOe (2100 kA / m) energy product (BH) max - 30-38.9 MG · E (240-310 kJ / m ³ ), with a high uniformity of the properties of magnets between batches and inside the batch - up to ± 5%, and yield over 90%.

 The results achieved are explained by the following.

 Using in the production of magnetic material the principle of obtaining a given material composition and, accordingly, its properties by mixing the base alloy and the additive alloy, each of which is enriched (depleted) (compared to the base) in at least one of the main elements (Nd, Pr, Dy , Tb, B, etc.), by calculating and compiling a mixture of powders, it is possible to precisely specify the composition of the final product and, in addition, to introduce alloying additives (for example, Dy, Tb, Ga, Zr, U, etc.) in small quantities into the desired place - in the intergrain regions of the magnetic mother ala, i.e. receive material of strictly specified composition and with a given distribution of elements. The same principle of mixing a base alloy with an alloy - additive allows to reduce the total content of alloying elements in the material, for example, Dy, Tb, Al, Ti, etc., in comparison with the well-known technology for manufacturing the final product from an alloy of the same composition obtained by smelting and thereby increase magnetic induction.

 In addition, the use of the principle of composing mixtures allows one to reduce the stringency of the requirements for the accuracy of the composition of the starting alloys - base and additives and thereby increase the yield of magnets, since by mixing alloys (base and additives) of different compositions it is easy to obtain the final product of the same composition and respectively with the same high properties. Using the principle of composing mixtures allows you to easily obtain the final product with a different combination of magnetic properties - with high residual induction and relatively low coercive force and vice versa - by using the same base alloy and different alloys of additives or their amount in the mixture.

The above-mentioned heating conditions of the press blanks lead to the creation of a uniform temperature field in each blank batch, which eliminates cracking and oxidation of the material during heating. In the process of heating the press blanks to a temperature of about 950 ^o C, they are degassed, i.e. removal from the surface of the powder preforms adsorbed in the process of grinding powders and pressing of gases, water and organic liquids. At a high heating rate (more than 50 ^o C / min), degassing can occur violently and lead to cracking of the workpieces, at low (less than 1 ^o C / min) degassing is unduly delayed and leads to the binding of adsorbed substances to the workpiece material in stable compounds (for example , oxides) and thereby change the composition of the material and worsen its properties, for example, to reduce the coercive force, and also unnecessarily loads equipment. Thus, the heating of the press blanks must be carried out stepwise at a controlled speed, depending on the mass of the charge, the method and environment for grinding powders, the method and the medium of pressing, so that the vacuum during heating is maintained at least 10 ^-3 mm RT. Art.

Sintering of heated preforms purified from volatiles is carried out in the temperature range from about 950 to about 1200 ^o C with an average temperature change rate of 0.1-40 ^o C / min, which allows to increase the yield of magnets by their properties and their uniformity.

 This phenomenon is associated with the following. There is a natural dispersion of powder particles in size and composition. In addition, the press blanks are also heterogeneous in density, especially large ones, and any sintering furnace is characterized by a certain temperature gradient. Therefore, when isothermal sintering is carried out, only part of the volume of the billet or only part of the volume of the cage in the furnace is the optimal time at the optimum temperature and reach a given density and level of magnetic properties. The remaining parts of large magnets or other magnets in the cage of optimal density and properties do not reach or, conversely, pass them. This determines the low level of magnetic properties and their uniformity.

Sintering at a temperature that is variable according to a certain law leads to the fact that each part of the volume of the billet or each part of the volume of the batch in the furnace is at the optimum time at the optimum temperature and reaches a given density and level of magnetic properties. The choice of law for changing the sintering temperature depends on the shape and size of the press blanks, on the method and environment of grinding powder and pressing, on the mass of the charge and the heating mode of the press blanks at least to a temperature of 950 ^o C.

 Carrying out the cooling operation, which has a stepwise nature, leads to an increase in the coercive force of the magnetic material according to the invention.

 The indicated range of average cooling rate is determined by the composition of the material, the mass and shape of the workpieces, and the mass of the charge.

At an average cooling rate of less than 1 ^o C / min, unreasonably high energy costs take place. At an average cooling rate of more than 200 ^o C / min, the yield of suitable magnets decreases due to their cracking due to the appearance of large internal stresses.

The proposed magnetic material with high magnetic properties and their homogeneity with a yield of magnets of more than 90% can be obtained by another method, including crushing each of the previously prepared base alloy and additive alloy to obtain crushed alloys, which are mixed and get a mixture of crushed alloys, the latter is sent in the grinding zone, where the specified mixture of crushed alloys is crushed to a particle size average particle size of 1-10 microns and get a mixture of powders sent to the pressing zone, in which an orienting magnetic field is created, and the mixture is subjected to pressure pressing, as a result of which a low-density preform is obtained, which is sent to the sintering zone to increase the preform density, which reaches at least 80% of theoretical, and a sintered preform is obtained, which is sent to the cooling zone and cooled , characterized in that the base alloy contains components in the following ratio, at.%:
at least one on rare earths selected from the group: neodymium and praseodymium - 11.0 - 17.0
at least one of the rare earth elements selected from the group: dysprosium and terbium - 0.01 - 0.1
at least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 0.01 - 1.5
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.01 - 1.0
cobalt - 0.01 - 1.4
boron - 4.8 - 8.5
iron - the rest
alloy - the additive contains components in the following ratio, at.%:
at least one of the rare earth elements selected from the group: neodymium and praseodymium - 25.0 - 11.0
at least one of the rare earth elements selected from the group: dysprosium and terbium - 10.0 - 0.1
at least one of the elements selected from the group; aluminum, niobium, chromium, gallium - 8.0 - 0.01
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 6.0 - 0.01
cobalt - 10.0 - 0.01
boron - 15.0 - 4.8
iron - the rest
at the same time, an additive of U oxides is introduced into the mixture of crushed alloys in an amount (at.%) of 0.001-0.025 and the fact that in the sintering zone a vacuum is created in the heating section from about 10 ^-1 to about 10 ^-6 mm Hg. and the low-density preform is heated stepwise with an average heating rate of from about 1 to about 50 ^° C / min to at least 950 ^° C, whereby a heated preform, free of volatiles, is obtained, which is sintered in the sintering section of the specified sintering zone in a temperature range from about 950 ^o C to about 1200 ^o C with an average rate of temperature change of 1-40 ^o C / min, and in the cooling zone, the sintered billet is cooled stepwise with an average cooling rate of 1-200 ^o C / min.

The magnetic material obtained by the above method has magnetic properties: residual induction Br = 1.1-1.3 T (11-13 kG), coercive force iHc-2100 kA / m (26 kOe), energy product (BH) max = 240-310 kJ / m ³ (30-39 MG · E), high uniformity of magnetic properties and yield. The implementation of this method reduces the cost of the manufacturing process of magnets due to the preparation of alloy additives in general industrial conditions, because it does not contain uranium.

It is recommended that when billets are heated to a temperature of about 950 ^o C with an average speed of 1-5 ^o C / min, sintering is carried out as continuous heating with an average speed of 1-5 ^o C / min. This mode should be used in the manufacture of magnets with a complex texture, for example, four-pole, and an average weight, for example, 10-100 g. In this case, smooth heating to the final compaction of the workpieces does not allow the resulting internal stresses to destroy the workpiece.

It is advisable when heating preforms to a temperature of 1075 ^o C with an average speed of 5-15 ^o C / min sintering is carried out as cyclic heating and cooling with an amplitude of 20-250 ^o C. This mode should be used mainly when sintering preforms with a low initial density and a large mass, for example, 0.5-3 kg. With this sintering mode, each volume of the billet or each part of the cage in the furnace is at the optimum time at the optimum temperature and reaches the specified density and level of magnetic properties, which improves the uniformity of the magnets in properties and increases the yield.

It is advisable to heat the preforms to a temperature of about 1200 ^o C with an average speed of 5-20 ^o C / min. Sintering is carried out as continuous cooling with an average speed of 1-5 ^o C / min. This mode should be used when sintering small-sized billets with a high initial density. With this sintering mode, the process of compaction of the workpieces is accelerated, which reduces production costs.

It is possible, before pressing, to mix the powder mixture with the lubricant in a ratio of 1: 0.5--1: 7.5 and to carry out pressing in a magnetic field with a strength of about 160 kA / m at a specific pressure of 0.05-1.5 t / cm ² with continuous removing grease from the pressing zone. This technique should be used in the mass production of magnets when high pressing performance, magnetic properties and yield are required. Ethyl and / or polyvinyl alcohol, toluene, etc. should be used as a lubricant.

 The increase in productivity and yield of magnets due to the ease of automation of the process of pressing the powder in a magnetic field and increase the life of the press equipment and tooling in connection with a decrease in the specific pressing pressure.

 The increase in the yield of suitable magnets, magnetic properties and their uniformity is due to an increase in the degree of magnetic texture and its uniformity due to more favorable texturing conditions (with lubrication) and soft pressing conditions (reduction in specific pressing pressures).

 The upper and lower limits of the ratio of the powder weights to the lubricant are determined by the specifics of the dosage and the supply of the wet press from the press feeder and dispenser to the mold. The indicated ratio of weights also determines the maximum degree of magnetic texture.

The lower pressure limit of 0.05 t / cm ² during pressing is limited by the minimum strength of the press blanks. The upper limit of 1.5 t / cm ² - the degree of magnetic texture: the application of pressure in excess of 1.5 t / cm ² with the mutually parallel application of a magnetic field and pressure reduces the degree of magnetic texture below 80%.

Brief Description of the Drawings
Other objectives and advantages of the invention will become more apparent from the following specific examples of its implementation and the drawings, in which:
FIG. 1 is a graph of the coercive force iHc of a material versus uranium (U) content;
FIG. 2 is a flowchart of a manufacturing process for manufacturing a magnetic material;
FIG. 3 is a diagram of a temperature change in a heat treatment zone during the manufacturing of a magnetic material;
FIG. 4 is a flowchart of a manufacturing process for manufacturing a magnetic material;
FIG. 5 is a flowchart of a manufacturing process for manufacturing a magnetic material.

The magnetic material according to the invention contains Fe-B-Co-R, where R is the sum of R ₁ and R ₂ , wherein R ₁ is at least one of the rare earth elements selected from the group of neodymium (Nd) and praseodymium ( Pr), a R ₂ is at least one of the rare earths selected from the group of dysprosium (Dy) and terbium (Tb), and additive M, which is the sum of M ₁ and M ₂ , wherein M ₁ is at least , one of the elements selected from the group aluminum (Al), niobium (Nb), chromium (Cr), gallium (Ga), and M ₂ is at least one of the elements selected m from the group titanium (Ti), hafnium (Hf), zirconium (Zr), vanadium (V), tantalum (Ta), scandium (So) and uranium (U) of the following isotopic composition, at.% uranium 338 - 99.28 -99.9999, uranium 235 - 0.0001-0.72, contains components in the following ratio, at.%:
at least one of the rare earth elements selected from the group: neodymium and praseodymium - 12.0 - 17.0;
at least one of the rare earth elements selected from the group: dysprosium and terbium - 0.1 to 5.0;
at least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 0.5 to 4.0;
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.1 - 1.5;
boron - 6.5 - 8.5
iron is the rest.

 characterized in that the uranium is contained in an amount (at.%): 0.001-0.025, and cobalt - 0.1-1.5.

Such a magnetic material, according to the invention, has high magnetic properties, in particular, has an increased value of the coercive force iHc of more than 25 kOe (1990 kA / m) with (BH) max = 29-36 MG · E (230.8-286.6 kJ / m ³ ).

With the introduction of uranium, the magnetic isolation of the grains of the main phase of the type R ₂ Fe ₁₄ B is improved due to the formation of a uranium-containing eutectic and the formation on the surface of the grains of the main phase of the type R ₂ Fe ₁₄ B a thin (fraction of microns thick) film enriched with uranium. In addition, the dissolution of uranium in the main phase, although insignificant, can lead to a local increase in the anisotropy field of the main phase and thereby increase the coercive force, as can be seen from FIG. 1 graph of iHc versus uranium content.

 The above magnetic material is obtained by the method according to the invention. In FIG. 2 shows a block diagram of a technological process (method), according to the invention, the manufacture of magnetic material.

Base alloy containing components in the following ratio, at.%:
at least one of the rare earth elements selected from the group: neodymium and praseodymium - 11.0 - 17.0
at least one of the rare earth elements selected from the group: dysprosium and terbium - 0.01 - 0.1
at least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 0.01 - 1.5
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.01 - 1.0
cobalt - 0.01 - 1.4
boron - 4.8 - 8.5
iron - the rest
obtained, for example, by vacuum induction smelting, is fed into crushing zone 1 (Fig. 2).

Alloy is also supplied to the same zone - an additive containing components in the following ratio: at.%:
at least one of the rare earth elements selected from the group: neodymium and praseodymium - 25.0 - 11.0
at least one of the rare earth elements selected from the group: dysprosium and terbium - 10.0 - 0.01
at least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 8.0 - 0.1
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 6.0 - 0.01
cobalt - 10.0 - 0.01
boron - 15.0 - 4.8
uranium - 15.0 - 0.002
iron - the rest
obtained, for example, by vacuum induction smelting.

 The compositions of the base alloy and alloy additives are shown in table 1.

 In crushing zone 1 (Fig. 2) crushing is carried out to a particle size of 100 μm - 1 mm of alloys, and then crushed alloys are fed into mixing zone 2 for mixing in a ratio of 1: 1 - 1:25, which provides a material of a given composition (see table 2).

 The resulting mixture of crushed alloys is sent to grinding zone 3, where the specified mixture of crushed alloys is crushed to an average particle size of about 1-10 microns.

The resulting mixture of powders is sent to pressing zone 4, in which an orienting magnetic field with a strength of 160 kA / m to 800 kA / m is created and the mixture is pressed by pressure from 10 kg / cm ² to 10 t / cm ² , resulting in a low workpiece density, which is sent to the heat treatment zone 5 to obtain a magnetic material with a high density and coercive force.

In the heat treatment zone 5 (see FIG. 3), a vacuum is created in the heating section 5a with a depth of from about 10 ⁻¹ to about 10 ⁻⁶ mm Hg. and heating the preform with a low density stepwise with an average heating rate of from about 1 to about 50 ^° C / min, at least to a temperature of 950 ^° C, resulting in a heated preform purified from volatiles. The latter is sintered in the sintering section 5c of the specified heat treatment zone 5 in the temperature range from about 950 ^° C to about 1200 ^° C with an average rate of temperature change of 1-40 ^° C / min, resulting in a preform with a density of at least 80% of theoretical . After sintering, the preforms with a high density are sent to the cooling section 5c, where the cooling is carried out stepwise with an average cooling rate of 1-200 ^° C / min, as a result of which a preform with a microstructure providing a high coercive force is obtained. From the heat treatment zone 5, the preforms enter the magnetization zone 6, as a result of which a preform with a high coercive force of more than 2000 kA / m (25 kOe) is obtained.

 In the case of increased requirements for the geometry of the magnets and their corrosion resistance, the workpieces, for example, enter the grinding and tumbling zone before entering the magnetization zone, and then to the protective coating zone, which increases the corrosion resistance of the magnets.

The magnetic material according to the invention can be obtained by the method according to the invention, in which a base alloy, the composition of which is similar to the above, and an alloy alloy containing components in the following ratio, at.%:
at least one of the rare earth elements selected from the group: neodymium and praseodymium - 25 - 11
at least one of the rare earth elements selected from the group: dysprosium and terbium - 10.0 - 0.01
at least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 8.0 - 0.01
at least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 6.0 - 0.01
cobalt - 10.0 - 0.01
boron - 15.0 - 4.8
iron - the rest
sent to zone 7 crushing (Fig. 4) to obtain crushed to a particle size of 100 microns - 1 mm alloys, and then crushed alloys and additive - uranium oxide is fed into mixing zone 8. The compositions of the base alloy, alloy additives and additives are shown in table 3. The resulting mixture is sent to zone 9 grinding and then the process is carried out in accordance with the foregoing.

It is recommended that when billets are heated to a temperature of about 950 ^o C with an average speed of 1-5 ^o C / min, sintering is carried out as continuous heating with an average speed of 1-5 ^o C / min. This mode should be used in the manufacture of magnets with a complex texture, for example, four-pole, and an average weight, for example, 10-100 g. In this case, smooth heating to the final compaction of the workpieces does not allow the resulting internal stresses to destroy the workpiece.

It is advisable when heating preforms to a temperature of 1075 ^o C with an average speed of 5-15 ^o C / min sintering is carried out as cyclic heating and cooling with an amplitude of 20-250 ^o C. This mode should be used mainly when sintering preforms with a low initial density and a large mass, for example, 0.5-3 kg. With this sintering mode, each volume of the billet or each part of the cage in the furnace is at the optimum time at the optimum temperature and reaches the specified density and level of magnetic properties, which improves the uniformity of the magnets in properties and increases the yield.

It is advisable to heat the preforms to a temperature of about 1200 ^o C with an average speed of 5-20 ^o C / min. Sintering is carried out as continuous cooling with an average speed of 1-5 ^o C / min. This mode should be used when sintering small-sized billets with a high initial density. With this sintering mode, the process of compaction of the workpieces is accelerated, which reduces production costs.

To increase the productivity of the pressing process, reduce energy consumption, increase the durability of the press tool and increase the degree of magnetic texture and, accordingly, residual induction, it is advisable to grind a mixture of powders of the base alloy and additive alloy or base alloy, additive additive and uranium oxide into the press preparation zone 10 mass (Fig. 5), in which the powders are mixed with lubricant in a ratio of 1: 1 to 10: 1. The resulting press mass is fed into the pressing zone, in which an orienting magnetic field is created with a strength of 160 kA / m to 400 kA / m and the press mass is subjected to pressing with a pressure of 10 kg / cm ² to 1500 kg / cm ² while continuously lubricating, as a result, a low-density preform is obtained, which is sent to the heat treatment zone to obtain a magnetic material with a high density and coercive force.

 The alloy additive can be obtained by high-speed quenching of the melt in order to obtain an amorphous or microcrystalline structure of particles. The use of alloy additives in this state with a high degree of activity increases the effectiveness of the alloy additives in a mixture of powders and increases the magnetic characteristics of the material.

 The following are the compositions of the magnetic material according to the invention obtained by the manufacturing methods according to the invention.

Example 1
Take the base alloy of the composition Fe-1.4Co-8.5V-17Nd-0.1Dy-1.4Al-0.9Ti-0.1Sc and the alloy additive Fe-1.6Co-7.5B-11Nd-2.9Dy -0.6Al-0,1Ti-0,1Sc-0,03U obtained by vacuum induction melting, and feed them into zone 1 crushing (Fig. 2). In this zone, the alloy ingots are individually crushed to a particle size of 500 μm, and then the crushed alloys are fed into zone 2 for preparing the mixture for mixing in a ratio that ensures the preparation of Fe-1,5Co-8B-14Nd-1,5Dy-1Al-0 material 5Ti-0.1Sc-0.015U (p. 35 Tab. 2-3). The resulting mixture of crushed alloys is sent to grinding zone 3, where the mixture is crushed to an average particle size of 3 μm. The resulting powder is sent to pressing zone 4, in which an orienting magnetic field of 600 kA / m is created and pressed into four-pole blanks weighing about 80 g at a specific pressure of 5 t / cm ² , resulting in blanks with a density of about 70%, which sent to the heat treatment zone 5. In the heat treatment zone 5, a vacuum of about 10 ⁻³ mmHg deep is created in the heating section 5a. Art. and the billets are heated stepwise at an average speed of 3 ^o C / min to a temperature of 950 ^o C, and when the billets reach a temperature of 200 ^o C, hold for 60 minutes, then they are subjected to further heating to 600 ^o C and again hold for 60 min After reaching a temperature of 950 ^o C as a result of degassing get heated and purified from volatile substances preforms, which are fed to the sintering site. Sintering is carried out as continuous heating to a temperature of 1180 ^o C with an average speed of 5 ^o C / min, resulting in a workpiece with a density of 95%. After sintering, the preforms are sent to the cooling section 5c, where the cooling is carried out stepwise with an average cooling rate of 11 and / min, and when the preforms reach a temperature of 900 ^o C and 520 ^o C, they are held for 30 and 60 minutes, respectively, resulting in a microstructure, providing high coercive force. After cooling, the workpieces are sent to the magnetization zone.

Example 2
Take a base alloy of the composition Fe-0.01Co-4.8B-11Nd-0.01Dy-0.01Al-0.01Ga-0.01Sc and an alloy-additive of the composition Fe-3.7Co-13B-22Nd-5Dy-3, 7Al-0.09Ga-1.15Sc-0.035U, obtained by the method of calcium thermal reduction, and feed them into zone 1 crushing (figure 2). In this zone, the alloy ingots are individually crushed to a particle size of 500 μm, and then the crushed alloys are fed into the mixture preparation zone for mixing in a ratio that ensures the preparation of Fe-1Co-7B-14Nd-1,4Dy-1Al-0.03Ga-0 material 05Sc-0.01U (p. 66 tab. 2-5). The resulting mixture of crushed alloys is sent to grinding zone 3, where the mixture is crushed to an average particle size of 2.5 μm. The resulting powder is sent to pressing zone 4, in which an orienting magnetic field of 800 kA / m (10 kOe) is created and pressed in the form of prismatic blanks weighing about 1.5 kg at a specific pressure of 1 t / cm ² , resulting in blanks with a density about 60%, which are sent to heat treatment zone 5. In the heat treatment zone 5, a vacuum is created in the heating section 5a with a depth of 10 ^-1 mm Hg. and the workpieces are heated stepwise at an average speed of 7 ^o C / min, to a temperature of 1120 ^o C, and when the workpieces reach a temperature of 250 ^o C, exposure is carried out for 30 minutes, then they are further heated to 650 ^o C and again exposure is carried out for 30 min. After reaching a temperature of 1120 ^o C as a result of degassing, heated and purified from volatile substances blanks are fed to the sintering section 5c. Sintering is carried out as a cyclic heating and cooling with an amplitude of 50 ^o C with an average rate of temperature change of 2.5 ^o C / min, resulting in a workpiece with a density of 98%. After sintering, the preforms are sent to the cooling section 5c, where the cooling is carried out stepwise with an average cooling rate of 50 ^o C / min, and when the preforms reach a temperature of 950 ^o C and 600 ^o C, they are held for 5 and 10 minutes, respectively, resulting in a microstructure providing high coercive force. After cooling, the workpieces are sent to the magnetization zone.

Example 3
A magnetic composition material similar to that described in Example 1 was prepared as follows.

 Take the base alloy of the composition Fe-1Co-6.5B-12Nd-0.8Dy-0.75Al-0.5Ti-0.01Sc and the alloy additive Fe-3.8Co-15B-23Nd-4.75Dy-2.1Al -0.5Ti-0.7Sc obtained by the method of vacuum induction smelting, and feed them into the crushing zone 7 (Fig. 4). In this zone, the alloy ingots are individually crushed to a particle size of 500 μm, and then the crushed alloys and the additive - uranium oxide are fed into the mixture preparation zone 8, in which they are mixed in a ratio that ensures the production of a magnetic material with the composition Fe-1,5Co-8B- 14Nd-1,5Dy-1Al-0,5Ti-0,1Sc-0,015U (p. 35 tab. 2-3). The resulting mixture is sent to grinding zone 9, where the mixture is crushed to an average particle size of 3 μm and then the process is carried out in accordance with the foregoing in example 1.

Example 4
Take a base alloy of the composition Fe-0.5Co-6B-14Nd-0.5Dy-1.85Al-0.3Ti-0.07Sc and an alloy-additive of the composition Fe-0.5Co-11B-20Nd-2Dy-4Al-1, 3Ta-0,22Sc-0,036U obtained by induction smelting, and feed them into the crushing zone 1 (Fig. 2). In this zone, the alloy ingots are individually crushed to a particle size of 500 μm, and then the crushed alloys are fed into zone 2 for preparing the mixture for mixing in a ratio that ensures the preparation of Fe-0.5Co-7B-15Nd-0.8Dy-2Al-0 material 5Ti-0.1Sc-0.025U (Clause 4, Table 2-1). The resulting mixture of crushed alloys is sent to grinding zone 3, where the mixture is crushed to an average particle size of 3 μm. The resulting powder is sent to pressing zone 4, in which an orienting magnetic field of 800 kA / m (10 kOe) is created and pressed into disk blanks weighing about 1 g at a specific pressure of 0.5 t / cm ² , resulting in blanks with a density about 60%, which are sent to heat treatment zone 5. In the heat treatment zone 5, a vacuum of 10 mmHg deep is created in the heating section 5a. Art. and the billets are heated stepwise at an average speed of 20 ^o C / min, to a temperature of 1200 ^o C, and when the billets reach a temperature of 300 ^o C, hold for 15 minutes, then they are subjected to further heating to 700 ^o C and again hold for 20 minutes. After reaching a temperature of 1200 ^o C as a result of degassing get heated and purified from volatile substances billets, which are fed to the sintering section 5B. Sintering is carried out as continuous cooling with an average speed of 5 ^o C / min to a temperature of 1000 ^o C, resulting in a workpiece with a density of 95%. After sintering, the preforms are sent to the cooling section 5c, where the cooling is carried out stepwise with an average cooling rate of 200 ^o C / min, and when the preforms reach a temperature of 550 ^o C, holding is carried out for 1 min, resulting in the formation of a microstructure that provides high coercive force. After cooling, the workpieces are sent to the magnetization zone.

 The preferred embodiments described above are provided by way of example only and are not intended to limit the scope of the invention. Various modifications and embodiments of the invention are possible without deviating from its essence and scope, as defined by the following patent claims.

Claims (10)

1. A magnetic material containing Fe-B-Co-R, where R is the sum of R ₁ and R ₂ , and R ₁ is at least one of the rare earth elements selected from the group of neodymium (Nd), praseodymium (Pr), and R ₂ is at least one of the rare earths selected from the group of dysprosium (Dy), terbium (Tb), and additive M, which is the sum of M ₁ and M ₂ , wherein M ₁ is at least one of the elements selected from the group of aluminum (Al), niobium (Nb), chromium (Cr), gallium (Ga), and M ₂ is at least one element selected from the group consisting of titanium (Ti), hafnium (Hf), zirconium (Zr), vanadium (V), tantalum (Ta), scandium (Sc) and uranium (U) following the isotopic composition at. %: uranium 238 - 99.28 - 99.9999, uranium 235 - 0.0001 - 0.72, characterized in that it contains components in the following ratio, at. %:
At least one of the rare earth elements selected from the group: neodymium and praseodymium - 12.0 - 17.0
At least one of the rare-earth elements selected from the group: dysprosium and terbium - 0.1 - 5.0
At least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 0.5 - 4.0
At least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.1 - 1.5
Boron - 6.5 - 8.5
Cobalt - 0.1 - 1.5
Uranus - 0.001 - 0.025
Iron - Else
2. A method of obtaining a magnetic material, including crushing a base alloy and an additive alloy, mixing alloys in a ratio that provides a given composition of material, grinding a mixture of crushed alloys to an average particle size of 1 to 10 microns, pressing a mixture of powders in an orienting magnetic field to obtain low density preform, sintering the preform to obtain a density of at least 80% of the theoretical, at 950 - 1200 ^o C, and cooling the sintered body, wherein the base alloy contains com onenty in the following ratio, at.%:
At least one of the rare earth elements selected from the group: neodymium and praseodymium - 11.0 - 17.0
At least one of the rare earth elements selected from the group: dysprosium and terbium - 0.01 - 0.1
At least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 0.01 - 1.5
At least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.01 - 1.0
Cobalt - 0.01 - 1.4
Boron - 4.8 - 8.5
Iron - Else
and the alloy additive contains components in the following ratio, at.%:
At least one of the rare earth elements selected from the group: neodymium and praseodymium - 25.0 - 11.0
At least one of the rare earth elements selected from the group: dysprosium and terbium - 10.0 - 0.01
At least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 8.0 - 0.01
At least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 6.0 - 0.01
Cobalt - 10.0 - 0.01
Boron - 15.0 - 4.8
Uranus - 1.5 - 0.002
Iron - Else
and the fact that the heating of the low-density preform for sintering is carried out stepwise with an average heating rate of from about 1 to about 50 ^o C / min to at least 950 ^o C in a vacuum with a depth of from about 10 ^-1 to about 10 ^-6 mm Hg ., sintering in a given temperature range is carried out with a temperature change rate of 1 - 40 ^o C / min, and the sintered billet is cooled stepwise at an average speed of 1 - 200 ^o C / min. 3. The method according to claim 2, characterized in that when the billet is heated to a temperature of about 950 ^o C with an average speed of 1 - 5 ^o C / min, sintering is carried out as continuous heating with an average speed of 1 - 5 ^o C / min. 4. The method according to claim 2, characterized in that when the billet is heated to a temperature of about 1075 ^o C with an average speed of 5 - 15 ^o C / min, sintering is carried out as a cyclic heating and cooling with an amplitude of 20 - 250 ^o C. 5. The method according to claim 2, characterized in that when the billet is heated to a temperature of about 1200 ^o C with an average speed of 5 - 20 ^o C / min, sintering is carried out as continuous cooling with an average speed of 1 - 5 ^o C / min. 6. The method according to claim 2, characterized in that the mixture of powders is mixed with lubricant in a ratio of 1: 0.5 - 1: 1.5, pressing is carried out in a magnetic field with a strength of about 240 kA / m at a specific pressure of 0.05 - 1 , 5 t / cm ² and the continuous removal of grease from the cavity of the mold. 7. A method of producing a magnetic material, including crushing a base alloy and an additive alloy, mixing alloys in a ratio that provides a given composition of material, grinding a mixture of crushed alloys to an average particle size of 0.1 - 5.0 microns, pressing a mixture of powders in orienting a magnetic field to obtain a low density preform, sintering the preform to obtain a density of at least 80% of theoretical at 950 - 1200 ^o C, and cooling the sintered body, wherein the base alloy contains Components in the following ratio, at.%:
At least one of the rare earth elements selected from the group: neodymium and praseodymium - 11.0 - 17.0
At least one of the rare earth elements selected from the group: dysprosium and terbium - 0.01 - 0.1
At least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 0.01 - 1.5
At least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 0.01 - 1.0
Cobalt - 0.01 - 1.4
Boron - 4.8 - 8.5
Iron - Else
alloy additive contains components in the following ratio, at.%:
At least one of the rare earth elements selected from the group: neodymium and praseodymium - 25.0 - 11.0
At least one of the rare earth elements selected from the group: dysprosium and terbium - 10.0 - 0.01
At least one of the elements selected from the group: aluminum, niobium, chromium, gallium - 8.0 - 0.01
At least one of the elements selected from the group: titanium, hafnium, zirconium, vanadium, tantalum, scandium - 6.0 - 0.01
Cobalt - 10.0 - 0.01
Boron - 15.0 - 4.8
Iron - Else
at the same time, uranium oxides are added to the mixture of crushed alloys in an amount, at.%: 0.001 - 0.025, and the fact that the low-density preform for sintering is heated stepwise with an average heating rate of from about 1 to about 50 ^o C / min 950 ^o C in vacuum with a depth of from about 10 ^-1 to about 10 ^-6 mm RT. Art. , sintering in a given temperature range is carried out with a temperature change rate of 1 - 40 ^o C / min, and the sintered billet is cooled stepwise at an average speed of 1 - 200 ^o C / min. 8. The method according to claim 7, characterized in that when the billet is heated to 950 ^o C with an average speed of 1 - 5 ^o C / min, sintering is carried out as continuous heating with an average speed of 1 - 5 ^o C / min. 9. The method according to claim 7, characterized in that when the billet is heated to a temperature of about 1075 ^o C with an average speed of 5 - 15 ^o C / min, sintering is carried out as a cyclic heating and cooling with an amplitude of 20 - 250 ^o C. 10. The method according to claim 7, characterized in that when the billet is heated to a temperature of about 1200 ^o C with an average speed of 5 to 20 ^o C / min, sintering is carried out as continuous cooling with an average speed of 1 to 5 ^o C / min. 11. The method according to p. 7, characterized in that the mixture of powders is mixed with lubricant in a ratio of 1: 0.5 - 1: 1.5, pressing is carried out in a magnetic field with a strength of about 240 kA / m at a specific pressure of 0.05 - 1 , 5 t / cm ² and the continuous removal of grease from the cavity of the mold.

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