Soft magnetic amorphous fe-co alloy with high saturation magnetization

Abstract

The invention relates to the field of metallurgy, in particular to amorphous soft magnetic alloys based on Fe-Co, obtained by casting the melt onto the surface of the crystallizer and its high-speed quenching, which are used as an integral part of various devices, in particular transformers, motors, generators - devices whose characteristics are based on the effect of electromagnetic induction. The technical result of the proposed invention is to obtain an extremely high value of saturation magnetization of 1.94-2.01 T, while the coercive force is 6.6-10 A / m, the maximum permeability is 5000 ~ 14000. The present invention has the advantages of a simple heat treatment mode and a low annealing temperature, which significantly reduces the cost of the process. The technical result is achieved as follows: a soft magnetic material based on iron and cobalt, containing boron, silicon, phosphorus and carbon in the following ratio of components in at. %: Fe – 58.2 – 68.0; Со – 16.4 – 25.2; B – 13 – 16; Si – 0.9 – 1.1; P – 0 – 1.1; C – 0 – 1.1.

Description

[0001] Soft magnetic amorphous Fe-Co alloy with high saturation magnetization

[0002] Field of Invention. The invention relates to the field of metallurgy, in particular to amorphous soft magnetic alloys based on Fe-Co, obtained by casting a melt onto the surface of a crystallizer and its high-speed quenching, which are used as an integral part of various devices, in particular transformers, motors, generators - devices whose characteristics are based on the effect of electromagnetic induction.

[0003] The amorphous structure of the alloy ribbons is obtained by quenching the liquid melt on a rapidly rotating copper crystallizer disk, the cooling rate of which is sufficient to freeze the disordered arrangement of atoms at a large distance at room temperature.

[0004] The amorphous structure of Fe-Co based alloy ribbons contributes to their soft magnetic properties with lower power losses, higher saturation magnetization and relatively good glass-forming ability compared to conventional Fe-based amorphous alloy ribbons.

[0005] Prior Art. The patent documents presented below are the closest in composition to the developed materials based on Fe-Co, however, in the chemical composition they have an additional additive of Cu and are characterized by a nanocrystalline structure. A nanocrystalline soft magnetic material of the composition Fei0o-x-y-aCoaCuxByis known (US 8298355 B2 published on 18.02.2010), where x is in the range from 1 to 3 (inclusive), y from 10 to 20 and a from 10 to 25, while grains of 60 nm or less in size are partially present in the structure, formed as a result of annealing, and the alloy has a saturation induction of 1.85 T or more and a coercive force of 200 A / m or less.

[0006] The disadvantage of the invention is the high coercive force of the alloy compared to the proposed material.

[0007] Alloys of the composition Fe(100-X-Y-Z)BxPYCuz (RU 2483135 Cl, published 27.05.2013) with an amorphous phase as the main phase, where 79<100- X-Y-Z< 86 at.%, 4<X<13 at.%, 1<Y<1O at.% and 0.5<Z<1.5 at.%, having a saturation magnetic induction of 1.6 T and a coercive force of 20 A / m are known. In this case, the method for forming the nanocrystalline structure of the alloys consists in heat treatment in the temperature range from Txl-50°C and Tx2, where Txiand Tx2are the temperatures of the onset of the first and second crystallization, respectively.

[0008] The disadvantage of the invention is the low values of saturation induction and high coercive force compared to the proposed material.

[0009] The closest in composition to the proposed alloy is an amorphous alloy based on the Fe-Co system with the composition FeaCobSicBdCue(US 2020 / 0335246 Al published on 10 / 22 / 2020), where a = 60-85, b = 1-20, c = 0-4, d = 12-16, e = 0.5-1.5 and a + b + c + d + e = 100, having a saturation induction of 1.79-1.86 T, a coercive force of 1.4-4.3 A / m, a magnetic permeability of 8000- 14000 and preferable heat treatment at temperatures of 290-370° for 5 to 30 minutes.

[0010] The disadvantage of the invention is the low induction values.

[0011] Disclosure of the Invention. The technical result of the proposed invention is to obtain an extremely high saturation magnetization value of 1.94-2.01 T, while the coercive force is 6.6-10 A / m, the maximum permeability is 5000 ~ 14000. The present invention has the advantages of a simple heat treatment mode and a low annealing temperature, which significantly reduces the cost of the process.

[0012] The technical result is achieved as follows: a soft magnetic material based on iron and cobalt, containing boron, silicon, phosphorus and carbon in the following ratio of components in at. %:

[0013] Fe - 58.2 - 68.0;

[0014] Co - 16.4 - 25.2;

[0015] B - 13 - 16;

[0016] Si - 0.9 - 1.1;

[0017] P - 0 - 1.1;

[0018] C - 0 - 1.1. The invention is explained in the figures, which shows: Fig. 1 - an X-ray diffraction pattern of the amorphous alloy Fe67.2Col6.8B15Sil after casting, obtained using monochromatic Cu-Ka radiation, Fig. 2 - the results of differential scanning calorimetry of the Fe67.2Col6.8B15Sil alloy, obtained at a heating rate of 0.67 °C / s, Fig. 3 - an X-ray diffraction pattern of the amorphous alloy Fe67.2Col6.8B15Sil after annealing, obtained using monochromatic Cu-Ka radiation, Fig. 4 - a hysteresis loop of the Fe67.2Col6.8B15Sil alloy in a heat- treated state, Fig. 5 - a graph of the dependence of the coercive force of the Fe67.2Col6.8B15Sil alloy on the annealing duration, Fig. 6 - X-ray diffraction pattern of the amorphous Fe67.2Col6.8B14SilCl alloy after casting, obtained using monochromatic Cu-Ka radiation, in Fig. 7 - results of differential scanning calorimetry of the Fe67.2Col6.8B14SilCl alloy, obtained at a heating rate of 0.67 °C / s, in Fig. 8 - X-ray diffraction pattern of the amorphous

[0019] Fe67.2Col6.8B14SilCl alloy after annealing, obtained using monochromatic Cu- Ka radiation, in Fig. 9 - hysteresis loop of the Fe67.2Col6.8B14SilCl alloy in the heat-treated condition, in Fig. 10 - graph of the dependence of the coercive force of the Fe67.2Col6.8B14SilCl alloy on the annealing duration, in Fig. 11 - X-ray diffraction pattern of amorphous Fe68Col7B13SilPl alloy after casting, obtained using monochromatic Cu-Ka radiation, in Fig. 12 - results of differential scanning calorimetry of Fe68Col7B13SilPl alloy, in Fig. 13 - X-ray diffraction pattern of amorphous Fe68Col7B13SilPl alloy after annealing, obtained using monochromatic Cu-Ka radiation, in Fig. 14 - hysteresis loop of Fe68Col7B13SilPl alloy in heat-treated condition, in Fig. 15 - graph of dependence of coercive force of Fe68Col7B13SilPl alloy on annealing duration.

[0020] Implementation of the invention

[0021] The alloy compositions for implementing the invention are described by the following formula (in at.%): FexCoyBaSibCcPd, where 58.2<x<68.0, 16.4<y<25.2, 13<a<16, 0.9<b<l.l, 0<c<l .l, 0<d<l .1 82<x+y<85, x+y+a+b+c+d=100. Based on the conducted studies, it was found that in this material, the elements - iron Fe and cobalt Co, are the main ferromagnetic elements, the combination of which provides increased magnetic properties of the material, their content is due to obtaining a high value of saturation induction of the proposed material, non-metallic elements - boron B, silicon Si, phosphorus P, in the specified quantities provide a high tendency of alloys to amorphization for obtaining materials in the form of ribbons with an initial amorphous structure.

[0022] The method for producing the said amorphous soft magnetic alloys based on Fe-Co in the above-mentioned implementation includes the following stages:

[0023] - Obtaining a high-purity master alloy from Fe, Co, B, Si, P and C with a selected atomic composition corresponding to the above-mentioned range.

[0024] - Preparation of a master alloy ingot in an arc melting furnace in an argon atmosphere.

[0025] - Remelting the obtained master alloy ingot in a rapid melt quenching machine with a linear rotation speed of the crystallizer of 40-50 m / s, the injection pressure and temperature are (1-3) 105Pa and 1250-1350°C, respectively.

[0026] - Annealing treatment is carried out at a temperature of 3OO-35O°C and annealing time of 5-30 min.

[0027] According to the invention, pure elements Fe, Co, Si, B, C and P are mixed according to atomic percentages to obtain a mixture in which said starting materials Fe, Co, Si, B, C preferably have a purity of> 99%, the master alloy Fe-8- 10 wt.%. P. It is important to use raw materials in lump form, in the invention powdery materials should be avoided.

[0028] After the mixture is obtained, it will be melted to obtain an ingot of the alloy. In the invention, said melting is preferably carried out in a vacuum arc melting furnace. It is necessary to control the homogeneity of the ingot, which is achieved by repeated remelting, approximately five to six times.

[0029] After the preparation of the alloy ingot, it is necessary to obtain metal ribbons using a melt quenching machine on a rotating copper crystallizer disk. It is preferable that the linear speed of the rotating disk is 40-50 m / s, the injection pressure is (1-3) 105 Pa and the melt temperature is 1250-1350 °C. The melt should be injected from a crucible with a linear or round nozzle no more than 0.5 mm thick or 0.7 mm in diameter, respectively. The distance between the edge of the crucible and the disk surface is 0.2 mm. The crucible should be made of materials inert with respect to the melt elements.

[0030] When the alloy of the present invention is produced by the above-mentioned method, a magnetic material having a saturation magnetic flux density of 1.94 T or more and a coercive force of 30 A / m or less is obtained.

[0031] The magnetic properties of the invention can be improved by annealing to undergo a structural relaxation process. Annealing can be carried out in air, in a vacuum or in an inert gas such as Ar or nitrogen. However, it is particularly preferable to carry it out in an inert gas environment. It is desirable that the maximum temperature during annealing is in a temperature range of 80° C below the initial temperature of the first crystallization stage (TXi). The duration of holding at a constant temperature should be less than 30 minutes.

[0032] When the alloy of the present invention is produced by the above-mentioned method, a magnetic material having a saturation magnetic flux density of 1.94 T or more and a coercive force of 8 A / m or less is easily obtained. Also, the material's bending ductility and a completely amorphous structure are maintained.

[0033] Example 1

[0034] Mix the raw materials Fe, Co, Si, B, the purity of which exceeds 99.9% according to the atomic percentage (molecular formula: Fe67.2C0i6.sB 15 Si 1) to obtain a mixture; place the said mixture in the crucible of the arc melting furnace and melt to obtain an ingot of the master alloy by repeated remelting with turning the ingot over five times.

[0035] The obtained master alloy was subjected to remelting in a machine for rapid quenching with a copper disk-crystallizer, thus obtaining a thin ribbon of amorphous alloy 1 mm wide and 15 pm thick. As a result of X-ray phase analysis (Fig. 1) and transmission electron microscopy, it was confirmed that the alloy mainly has an amorphous structure and also contains a very small volume fraction of nanosized clusters less than 7 nm in size. The clusters correspond to the solid solution phase having a body-centered cubic structure (bcc structure) based on FeCo.

[0036] A thin ribbon of amorphous alloy was heated to 340°C, which is 80°C lower than the first-stage crystallization temperature TXiin Fig. 2. The heating rate for annealing was 150°C / min and was maintained at this temperature for 2 min, followed by air cooling after removal from the furnace. The annealed sample was subjected to X-ray diffraction and transmission electron microscope structure observation. According to the results of the studies, it was confirmed that the alloy retains the structure obtained during quenching (Fig. 3). The magnetic flux density (saturation induction) at a magnetic field of 800 kA / m was designated as Bs (Fig. 4). The saturation induction Bswas 2.00 T, the coercive force Hcwas 9.5 A / m (Fig. 5), the magnetic permeability peat a frequency of 1 kHz and a field of 5 A / m was 13500.

[0037] Example 2

[0038] Mix the raw materials Fe, Co, Si, B, C, with a purity of more than 99.9% in accordance with the atomic content of the elements (molecular formula: Fe67.2Coi6.8Bi4SiiCi) to obtain a mixture; place the said mixture in the crucible of an arc melting furnace and melt to obtain an ingot of the master alloy by re-melting with turning the ingot over five times.

[0039] The molten alloy was quenched by single rolling melt spinner, and thus a thin amorphous alloy ribbon of 1 mm in width and 18 pm in thickness was obtained. As a result of observation using X-ray diffraction and transmission electron microscopy, it was confirmed that the alloy structure was completely amorphous (Fig. 6).

[0040] A thin ribbon of amorphous alloy was heated to 310°C, which is 80°C lower than the crystallization temperature of TXiin Fig. 7. The heating rate during annealing was 150°C / min and it was kept in this condition for 5 min, followed by air cooling after removal from the furnace. The annealed sample was analyzed by X-ray diffraction (Fig. 8) and by observing the structure using a transmission electron microscope. According to the results of the studies, it was confirmed that the alloy retains the structure obtained during quenching. The magnetic flux density at a magnetic field of 800 kA / m (saturation magnetization) was designated as Bs(Fig. 9). The saturation magnetization Bswas 1.99 T, the coercive force Hcwas 8.0 A / m (Fig. 10), and the magnetic permeability peat a frequency of 1 kHz and a field of 5 A / m was 5800.

[0041] Example 3

[0042] Mix the raw materials Fe, Co, Si, B, with a purity of more than 99.9%, and pre-melted master alloy Fe-8.8 wt. % P in accordance with the atomic content of the elements (molecular formula: FeggConSiiB^Px) to obtain a mixture; place the said mixture in the crucible of an arc melting furnace and melt to homogeneity of the chemical composition by volume, the master alloy is subjected to repeated remelting with the ingot being turned over five times.

[0043] The resulting master alloy was quenched using a rotating copper crystallizer disk, thus obtaining a thin ribbon of amorphous alloy 1 mm wide and 18 pm thick. As a result of observation using X-ray diffraction and transmission electron microscopy, it was confirmed that the alloy structure was completely amorphous (Fig. 11).

[0044] A thin ribbon of amorphous alloy was heated to 305°C, which is 80°C lower than the crystallization temperature of TXiin Fig. 12. The heating rate for annealing was 150°C / min and it was kept at this temperature for 15 min, followed by air cooling after removing from the furnace. The structure after annealing was analyzed by X-ray diffraction and transmission electron microscopy. According to the results of the studies, it was confirmed that the alloy retains the structure obtained during quenching (Fig. 13). The magnetic flux density at a magnetic field of 800 kA / m (saturation induction) was designated as Bs(Fig. 14). The saturation magnetic flux density Bswas 1.98 T, the coercive force Hcwas 7.0 A / m (Fig. 15), and the magnetic permeability peat a frequency of 1 kHz and a field of 5.0 A / m was 5800.

Claims

What is claimed is a1. A soft magnetic amorphous material based on iron and cobalt, containing boron, silicon, phosphorus and carbon in the following ratio of components in at. %:Fe- 58.2 -68.0;Co -16.4 -25.2;B-13-16;Si-0.9-1.1;P-0-1.1;C-0- 1.1.

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