Soft magnetic composite material, soft magnetic core ring and preparation method and application thereof

Abstract

The invention discloses a soft magnetic composite material, a soft magnetic core ring and a preparation method and application thereof. The preparation method of the soft magnetic composite material comprises the following steps: 1) providing raw materials according to the chemical composition of the soft magnetic material; the raw materials are smelted and rapidly hardened, and soft magnetic material master alloy is obtained; the chemical composition of the soft magnetic material is RE2 (FexCo1-x) 14B, and RE is selected from at least one of La, Ce, Pr, Nd, Sm, Eu and Gd; x is the atomic ratio of Fe, 0.7 < = x < = 1; 2) heating the soft magnetic material mother alloy in vacuum to obtain a soft magnetic material phase alloy; (3) the soft magnetic material phase alloy is prepared into powder with the particle size of 75-200 microns, and soft magnetic material powder is obtained; 4) mixing the soft magnetic material powder with an amino compound to obtain mixed powder; and heating the mixed powder under the conditions of protective gas and 300-600 DEG C to prepare the soft magnetic composite material. The prepared soft magnetic composite material is high in effective magnetic conductivity and low in unit volume power loss.

Description

TECHNICAL FIELD

[0001] The present application relates to a soft magnetic composite material, a soft magnetic core ring and a preparation method and use thereof. BACKGROUND

[0002] With the miniaturization of electrical equipment, the soft magnetic device in the electrical equipment needs to work at high frequency. However, if the insulation performance of the soft magnetic material used by the soft magnetic device is poor, it will lead to high eddy current loss. In the prior art, in order to reduce the eddy current loss of the soft magnetic material, at least one insulating layer is coated on the surface of the soft magnetic material to prepare a soft magnetic composite material, so as to increase the resistivity and reduce the eddy current loss.

[0003] CN109326405A discloses a preparation method of a high-thermal-conductivity insulating soft magnetic metal powder, which comprises the following steps: (1) configuring an insulating coating solution: weighing coating agents according to the proportion, the coating agents comprising nano-boron nitride, nano-aluminum nitride, nano-silicon nitride, sodium silicate and nano-zirconium oxide, adding the coating agents into distilled water and stirring and dissolving to obtain the insulating coating solution, the mass concentration of the insulating coating solution being 30-50 g / L; (2) coating metal powder with the insulating coating solution obtained in step (1) to prepare insulating powder; (3) preparing an adhesive; (4) preparing soft magnetic metal powder: adding the insulating powder into the adhesive to obtain the high-thermal-conductivity insulating soft magnetic metal powder. The preparation method adopts inorganic and organic components to coat at least two insulating layers to realize high resistance effect.

[0004] CN111902036A discloses an electromagnetic wave noise suppression sheet. The electromagnetic wave noise suppression sheet comprises a soft magnetic alloy powder, and a chemical composition molecular formula of the soft magnetic alloy powder is RE a M b X c , wherein a, b, c are atom numbers, 0.5 < a < 20, 1 < b < 50, 0 ≤ c < 10; RE is one or more of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y; M is one or more of Fe, Co, Ni, Mn, Cr, Ti, Cu, Zn, Al, Ga, Ag, Nb, Zr; X is one or more of elements N, B, Si, C, S, P, O. The electromagnetic wave noise suppression sheet can coat a layer of insulating layer or high resistance layer on the surface of the soft magnetic alloy powder, such as SiO2, TiO2, Al2O3, ZnO2 layer. The electromagnetic wave noise suppression sheet adopts an organic resistance layer with an average thickness of not less than 35 μm and an insulating layer with an average thickness of not less than 40 μm to realize high resistance effect.

[0005] The above soft magnetic material uses inorganic and organic two-phase coating components as an insulation layer to directly coat the soft magnetic material, which increases the heterogeneous interface, and has problems such as poor bonding force between the insulation layer and the soft magnetic material, uneven coating of the insulation layer, and easy breakage of the insulation layer during pressing, which directly affects the magnetic properties and service life of the soft magnetic material.

[0006] CN113066629A discloses an insulation coating method of a metal soft magnetic composite material. In the method, tetraethyl orthosilicate and trialkoxysilane are mixed and then added to anhydrous ethanol, an insufficient amount of water is first added dropwise, stirring is performed for 2-30 minutes after the dropwise addition is completed, soft magnetic metal powder is added, stirring is performed for 5-30 minutes, an insufficient amount of water is secondly added dropwise, stirring is performed for 2-20 minutes after the dropwise addition is completed, a sufficient amount of water is finally added dropwise, and stirring is continued for 5-60 minutes, followed by filtration, drying, and obtaining of the insulation coated powder. The insulation coating method uses a silicon-based material to realize uniform coating of the surface of the soft magnetic powder and forms a SiO2 coating layer after high-temperature annealing.

[0007] CN118588430A discloses a preparation method of a composite magnetic powder core. In the method, small-particle-size metal soft magnetic powder raised by vibration is collected by a magnetic adsorption method, the small-particle-size metal soft magnetic powder is mixed with metal soft magnetic powder of a larger particle size, and the mixture is coated with an insulating agent, pressed, and sintered to obtain the composite magnetic powder core. The insulating agent is at least one of a silicone resin, an epoxy-modified resin, an epoxy resin, a polyamide resin, a phenolic resin, and a polyimide resin.

[0008] The above soft magnetic material uses an organic material as an insulation layer to directly coat the soft magnetic material. In a subsequent high-temperature treatment process of the soft magnetic material, the surface organic structure is prone to decomposition, forming pores, which directly affects the magnetic properties and service life of the soft magnetic material. SUMMARY

[0009] Therefore, an object of the present application is to provide a preparation method of a soft magnetic composite material, which has excellent insulation performance, high effective permeability, and low power loss per unit volume. Another object of the present application is to provide a soft magnetic composite material prepared by the above preparation method. A further object of the present application is to provide a use of the above soft magnetic composite material in the preparation of a soft magnetic device for an electrical apparatus. A still further object of the present application is to provide a soft magnetic core ring. A still further object of the present application is to provide a preparation method of the above soft magnetic core ring.

[0010] The above objects are achieved by the present application which adopts the following technical solutions.

[0011] In one aspect, the present application provides a preparation method of a soft magnetic composite material, comprising the following steps:

[0012] 1) providing raw materials according to the chemical composition of the soft magnetic material; melting and rapidly solidifying the raw materials under a protective gas to obtain a soft magnetic material master alloy; the chemical composition of the soft magnetic material is RE2(Fe x Co 1-x ) 14 B, wherein RE is selected from at least one of La, Ce, Pr, Nd, Sm, Eu, Gd; x is the atomic ratio of Fe, 0.7≤x≤1;

[0013] 2) vacuum heating the soft magnetic material master alloy at 900-1300℃ to obtain a soft magnetic material phase alloy;

[0014] 3) preparing the soft magnetic material phase alloy into a powder with a particle size of 75-200μm to obtain a soft magnetic material powder;

[0015] 4) mixing the soft magnetic material powder with an amino compound according to a weight ratio of 1:3-15 to obtain a mixed powder; heating the mixed powder under a protective gas and at 300-600℃ to prepare a soft magnetic composite material.

[0016] According to the preparation method, preferably, RE is selected from at least one of Pr, Nd, Sm, Eu, Gd.

[0017] According to the preparation method, preferably, in step 2), the vacuum degree of the heating is 5Pa or less, and the heating time is 80-120h.

[0018] According to the preparation method, preferably, in step 4), the initial pressure of the protective gas is 0.08-0.5MPa; and the heating time is 15-50min.

[0019] According to the preparation method, preferably, in step 4), the amino compound is selected from at least one of C1-C5 monoamine, C2-C6 diamine, aniline and its derivatives, ammonium carbonate or bicarbonate, urea, melamine.

[0020] On the other hand, the application further provides a soft magnetic composite material prepared by any of the above preparation methods, which comprises a soft magnetic material and a coating layer coated on the surface of the soft magnetic material; the chemical composition of the coating layer is Fe4N.

[0021] In still another aspect, the application further provides the use of the above soft magnetic composite material in preparing a soft magnetic device for electrical equipment.

[0022] In yet another aspect, the application provides a soft magnetic core ring prepared from raw materials comprising the following weight parts:

[0023] 90-99 parts by weight of the soft magnetic composite material and 1-10 parts by weight of the binder.

[0024] According to the soft magnetic core ring, preferably, the binder is at least one selected from polyurethane, epoxy resin, phenolic resin, polyethylene resin and rubber.

[0025] In another aspect, the application further provides a preparation method of the soft magnetic core ring, comprising the following steps:

[0026] 1) mixing the soft magnetic composite material and the binder, and then placing in an organic solvent, followed by ultrasonic stirring to obtain a mixture; wherein the organic solvent is at least one selected from acetone, DMF, DMSO and THF;

[0027] 2) placing the mixture in a ring-shaped mold, and heating at 100-500 MPa and 70-150℃ to obtain the soft magnetic core ring.

[0028] The soft magnetic composite material has excellent insulation performance, high effective permeability and low power loss per unit volume. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Electron probe microanalysis image of Example 1. DETAILED DESCRIPTION

[0030] The application will be further described in conjunction with specific examples, but the scope of protection of the application is not limited thereto.

[0031] Preparation method of soft magnetic composite material

[0032] The preparation method of the soft magnetic composite material comprises a melting step, a phase control step, a powder preparation step and an insulation layer coating step. The following will be described in detail.

[0033] Melting step

[0034] The raw materials are provided according to the chemical composition of the soft magnetic material; the raw materials are melted and rapidly solidified under the protection of gas to obtain a soft magnetic material master alloy.

[0035] In the application, the chemical composition of the soft magnetic material is RE2(Fe x Co 1-x ) 14 B, the subscript represents the atomic ratio, x is the atomic ratio of Fe, 0.7≤x≤1.

[0036] According to one embodiment of the present application, the RE can be selected from at least one of La (lanthanum), Ce (cerium), Y (yttrium), Pr (praseodymium), Nd (neodymium), Sm (samarium), Eu (europium) Gd (gadolinium); preferably, the RE is selected from at least one of Pr, Nd, Sm, Eu, Gd; more preferably, the RE is selected from at least one of Sm, Eu.

[0037] According to one embodiment of the present application, x can be 0.7≤x≤1, preferably 0.8≤x≤1; more preferably 0.85≤x≤1. Such atomic ratio is more favorable for the soft magnetic material to have higher effective permeability and lower power loss per unit volume.

[0038] In the present application, the protective gas can be selected from at least one of nitrogen (N2), inert gas. The inert gas involved in the present application includes helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe). The protective gas is preferably at least one of nitrogen, helium, argon, more preferably at least one of nitrogen, argon.

[0039] In the present application, the smelting can use any smelting method known in the art, which is not particularly limited here. For example, it can be high-frequency arc melting method, medium-frequency casting method and tape casting method, etc.

[0040] According to one preferred embodiment of the present application, during smelting, the raw materials can be first placed in a vessel, and the raw materials are heated together with the vessel.

[0041] In the present application, the vessel can be any material known in the art for smelting. For example, it can be a copper mold or a quartz crucible.

[0042] According to one preferred embodiment of the present application, the smelting temperature can be 1000-1800℃, preferably 1200-1700℃, more preferably 1300-1600℃. The smelting time can be 5-30min, preferably 7-25min, more preferably 8-20min.

[0043] In the present application, the rapid solidification can be achieved using any rapid solidification equipment known in the art, which is not particularly limited here. For example, it can be a water-cooled copper mold. According to one preferred embodiment of the present application, during rapid solidification, the soft magnetic material master alloy liquid obtained by smelting can be cast into the rapid solidification equipment, and cooled for 10-60min, preferably 15-50min, more preferably 20-45min, to obtain the soft magnetic material master alloy.

[0044] The raw materials used in the present application can be single elements and / or intermediate alloys. The single elements and intermediate alloys can be commercially available products or prepared by existing preparation methods, and are not particularly limited herein. The purity of the single elements and intermediate alloys of the present application is at least technical purity (99.9 wt%).

[0045] Phase regulation step

[0046] The soft magnetic material phase alloy is obtained by vacuum heating the soft magnetic material master alloy at 900-1300°C.

[0047] According to one embodiment of the present application, the heating temperature can be 900-1300°C, preferably 950-1200°C, and more preferably 980-1100°C. The heating time can be 80-120h, preferably 90-115h, and more preferably 95-110h. The vacuum degree of the heating can be 5Pa or less, preferably 0.5-5Pa, and more preferably 1-4Pa. Such heating conditions can promote the formation of the 2:14:1 soft magnetic phase, and thus improve the saturation magnetic induction of the soft magnetic material.

[0048] In the present application, the phase regulation can be achieved in any vacuum heating device known in the art, and is not particularly limited herein.

[0049] Powdering step

[0050] The soft magnetic material phase alloy is ground to obtain a soft magnetic material powder having a particle size of 75-200μm.

[0051] According to one embodiment of the present application, the particle size of the powder can be 75-200μm, preferably 80-180μm, and more preferably 100-150μm.

[0052] In the present application, the powdering can be achieved in any crushing device known in the art, and is not particularly limited herein. For example, a superfine powder machine, a vertical pulverizer, a ball mill, an air jet mill, etc. can be used.

[0053] A reasonable particle size of the soft magnetic material powder is beneficial to the uniform and firm coating of the coating layer material on the surface of the soft magnetic material, and improves the insulation of the soft magnetic material, and thus improves the effective permeability of the soft magnetic material and reduces the power loss per unit volume of the soft magnetic material.

[0054] Insulating layer coating step

[0055] The soft magnetic material powder and the amino compound are mixed at a weight ratio of 1:3-15 to obtain a mixed powder; and the mixed powder is heated under the protection of a protective gas at 300-600°C to obtain a soft magnetic composite material.

[0056] According to one embodiment of the present application, the weight ratio of the soft magnetic material powder to the amino compound can be 1:3-15, preferably 1:5-13, and more preferably 1:8-12. Such a weight ratio is conducive to the coating layer material being more uniformly and firmly coated on the surface of the soft magnetic material, thereby improving the insulation performance of the soft magnetic material.

[0057] According to one embodiment of the present application, the amino compound can be at least one selected from C1-C5 monamines, C2-C6 diamines, aniline and its derivatives, ammonium carbonate or bicarbonate, urea, and melamine. The C1-C5 monamines can be at least one selected from C1-C3 monamines, and are preferably at least one selected from methylamine, ethylamine, and n-propylamine. The C2-C6 diamines can be at least one selected from C2-C4 diamines, and are preferably at least one selected from ethylenediamine, 1,3-propanediamine, and 1,4-butanediamine. The aniline and its derivatives can be at least one selected from aniline, N-methylaniline, N,N-dimethylaniline, o-toluidine, and p-toluidine, and are preferably at least one selected from aniline, N,N-dimethylaniline, and p-toluidine. According to one preferred embodiment of the present application, the amino compound is preferably at least one selected from methylamine, ethylamine, ethylenediamine, aniline, ammonium bicarbonate, urea, and melamine, and is more preferably at least one selected from ethylenediamine, ammonium bicarbonate, urea, and melamine. Such an amino compound can release ammonia gas upon heating at a temperature of 100°C or higher, thereby forming a nitride insulating coating layer on the surface of the soft magnetic material, which is conducive to improving the insulation performance of the soft magnetic material.

[0058] According to one embodiment of the present application, the heating temperature can be 300-600°C, preferably 350-550°C, and more preferably 400-500°C. The heating time can be 15-50 min, preferably 20-45 min, and more preferably 25-40 min. Such heating conditions are conducive to the formation of a nitride insulating coating layer on the surface of the soft magnetic material, which improves the insulation performance of the soft magnetic material, thereby increasing the effective permeability of the soft magnetic material and reducing the power loss per unit volume of the soft magnetic material.

[0059] According to one embodiment of the present application, the initial pressure of the protective gas can be 0.08-0.5 MPa, preferably 0.1-0.4 MPa, and more preferably 0.1-0.3 MPa.

[0060] The protective gas can be at least one selected from nitrogen (N2) and inert gases. The inert gases involved in the present application include helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). The protective gas is preferably at least one selected from nitrogen, helium, and argon, and is more preferably at least one selected from nitrogen and argon.

[0061] According to a preferred embodiment of the present application, no flow of nitrogen source gas (N2, NH3, etc.) and / or hydrogen gas is provided during the heating process. This can avoid safety problems caused by stable gas pressure and can reduce the complexity of the process.

[0062] In the insulating coating step of the present application, the heating can be performed in any heating device with inert atmosphere protection function known in the art, which is not particularly limited here. For example, an atmosphere furnace can be used.

[0063] <Soft magnetic composite material>

[0064] The present application also provides a soft magnetic composite material prepared by the above method.

[0065] The soft magnetic composite material of the present application comprises a soft magnetic material and a coating layer coated on the surface of the soft magnetic material.

[0066] The chemical composition of the soft magnetic material is as described above in the method, which is not repeated here.

[0067] According to an embodiment of the present application, the chemical composition of the coating layer is Fe4N.

[0068] In the soft magnetic composite material of the present application, the surface of the soft magnetic material is coated with a coating layer of nitride (Fe4N), thereby forming an insulating layer. Such a structure can improve the insulating performance of the soft magnetic material, increase the effective permeability of the soft magnetic material, and reduce the power loss per unit volume of the soft magnetic material.

[0069] <Use>

[0070] The present application also provides a use of the above soft magnetic composite material in the preparation of a soft magnetic device for electrical equipment.

[0071] In the present application, the soft magnetic composite material can be used as a material for preparing a soft magnetic device for electrical equipment.

[0072] In the present application, the effective permeability (μ e ) of a soft magnetic core ring made of the soft magnetic composite material of the present application under the condition of a magnetic induction intensity of 10 mT (millitesla) and a frequency of 100 kHz can be at least 12, preferably at least 12.3, and more preferably at least 12.5. The effective permeability under the condition of a magnetic induction intensity of 10 mT and a frequency of 1 MHz can be at least 12, preferably at least 12.4, and more preferably at least 12.6.

[0073] In the present application, the power loss per unit volume (P cv ) of a soft magnetic core ring made of the soft magnetic composite material of the present application under the condition of a magnetic induction intensity of 10 mT and a frequency of 100 kHz can be at most 40 kW / m 3 , preferably at most 39 kW / m3 , more preferably at most 38.5 kW / m 3 . The unit volume power loss under the condition of 10 mT magnetic induction and 1 MHz frequency can be at most 630 kW / m 3 , preferably at most 629.5 kW / m 3 , more preferably at most 629 kW / m 3 .

[0074] The soft magnetic composite material of the present application has excellent insulation performance, high effective permeability and low unit volume power loss, and is especially suitable for use as a soft magnetic device material for electrical equipment.

[0075] <Soft magnetic core ring>

[0076] The soft magnetic core ring of the present application is made of a material comprising the above-mentioned soft magnetic composite material and a binder.

[0077] According to one embodiment of the present application, the soft magnetic core ring is made of a material comprising the following raw materials by weight:

[0078] 100 parts by weight of the above-mentioned soft magnetic composite material and 1-10 parts by weight of a binder.

[0079] According to one embodiment of the present application, the binder can be used in an amount of 1-10 parts by weight, preferably 2-8 parts by weight, and more preferably 2.5-6 parts by weight. Such an amount ratio is advantageous for enhancing the structural strength and toughness of the soft magnetic core ring, improving the effective permeability of the soft magnetic core ring, and reducing the unit volume power loss of the soft magnetic core ring.

[0080] According to one embodiment of the present application, the binder can be selected from at least one of polyurethane, epoxy resin, phenolic resin, polyethylene resin, and rubber, preferably at least one of polyurethane, epoxy resin, phenolic resin, polyethylene resin, silicone rubber, and nitrile rubber, and more preferably at least one of polyurethane, epoxy resin, and phenolic resin.

[0081] In the present application, the effective permeability (μ e ) of the soft magnetic core ring under the condition of 10 mT (millitesla) magnetic induction and 100 kHz frequency can be at least 12, preferably at least 12.3, and more preferably at least 12.5. The effective permeability under the condition of 10 mT magnetic induction and 1 MHz frequency can be at least 12, preferably at least 12.4, and more preferably at least 12.6.

[0082] In the present application, the unit volume power loss (P cv ) of the soft magnetic core ring under the condition of 10 mT magnetic induction and 100 kHz frequency can be at most 40 kW / m 3 , preferably at most 39 kW / m3 more preferably 38.5 kW / m 3 The unit volume power loss under the condition of 10 mT magnetic induction intensity and 1 MHz frequency can be up to 630 kW / m 3 , preferably up to 629.5 kW / m 3 , more preferably up to 629 kW / m 3 .

[0083] <Method for preparing soft magnetic core ring>

[0084] The present application also provides a method for preparing the soft magnetic core ring as described above, which comprises a mixing step and a molding step. The following will be described in detail.

[0085] Mixing step

[0086] The soft magnetic composite material and the binder are mixed and then placed in an organic solvent, followed by ultrasonic stirring to obtain a mixture.

[0087] According to one embodiment of the present application, the organic solvent can be selected from at least one of acetone, DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), and THF (tetrahydrofuran), preferably at least one of acetone, DMF, and THF, and more preferably at least one of acetone and THF. According to one preferred embodiment of the present application, the amount of the organic solvent can be 1-5 mL, preferably 1.5-4.5 mL, and more preferably 2-4 mL, based on 1 g of the soft magnetic composite material.

[0088] In the present application, the ultrasonic stirring can be achieved in any ultrasonic stirring device known in the art, which is not particularly limited here. According to one embodiment of the present application, the frequency of the ultrasonic stirring can be 10-50 kHz, preferably 15-45 kHz, and more preferably 20-40 kHz. The time of the ultrasonic stirring can be 2-30 min, preferably 5-25 min, and more preferably 8-20 min. Such ultrasonic stirring conditions are conducive to the uniform mixing of the soft magnetic composite material and the binder, and are also conducive to the recovery and removal of the organic solvent.

[0089] Molding step

[0090] The mixture is placed in a ring-shaped mold and heated under the condition of 100-500 MPa and 70-150°C to obtain the soft magnetic core ring.

[0091] According to one embodiment of the present application, the pressure during heating can be 100-500 MPa, preferably 150-450 MPa, and more preferably 200-400 MPa. The temperature during heating can be 70-150°C, preferably 75-130°C, and more preferably 80-120°C. The time during heating can be 5-45 min, preferably 6-30 min, and more preferably 8-20 min. Such heating conditions are conducive to the formation of the soft magnetic core ring, and are more conducive to enhancing the structural strength and toughness of the soft magnetic core ring, improving the effective permeability of the soft magnetic core ring, and reducing the power loss per unit volume of the soft magnetic core ring.

[0092] According to one preferred embodiment of the present application, the outer diameter of the annular mold can be 6-20 mm, preferably 8-17 mm, and more preferably 10-16 mm. The inner diameter of the annular mold can be 3-15 mm, preferably 4-13 mm, and more preferably 5-12 mm. The material of the annular mold can be any high-temperature and high-pressure resistant material known in the art, which is not particularly limited here. For example, it can be steel, aluminum alloy, tungsten carbide, graphite, etc.

[0093] In the present application, the formation can be achieved in any heating and pressurizing equipment known in the art, which is not particularly limited here. For example, it can be achieved using an annular mold with heating function in cooperation with a hydraulic machine, or in a vacuum heating furnace in cooperation with a hydraulic machine, or using a powder servo forming machine with heating and pressurizing functions.

[0094] <Testing method>

[0095] Electron probe microanalysis: JXA-IHP200F Hyper probe type electron probe microanalyzer was used for detection.

[0096] Saturated magnetization test method

[0097] The soft magnetic composite material was weighed and placed in the sample cell, and then linked to the sample vibration magnetometer (VSM) test rod. The test temperature was room temperature, and the test range was ±20 KOe.

[0098] Saturated magnetization intensity measurement: Lakeshore 7410 analyzer was used for detection.

[0099] Soft magnetic core ring impedance test method

[0100] The wound (15 turns) soft magnetic core ring was placed in the B-H analyzer sample clamp, and the sample parameters (magnetic powder core inner diameter 6 mm, outer diameter 12 mm, thickness according to the actual pressing condition) were input.

[0101] The impedance analyzer program was set as: Bm mode (Bm=10 mT), test interval 100 KHz-3 MHz.

[0102] Soft magnetic core ring B-H loss test method

[0103] The soft magnetic core ring with 15 turns of winding was placed in the sample clamp of the B-H analyzer, and the sample parameters were input (the inner diameter of the magnetic powder core was 6 mm, the outer diameter was 12 mm, and the thickness was determined according to the actual pressing condition).

[0104] The impedance analyzer program was set as follows: Bm mode (Bm = 10 mT), and the test interval was 100 KHz-3 MHz.

[0105] The measurement of magnetic permeability and magnetic loss: both were detected by using IWATSU SY8218 type B-H analyzer.

[0106] <Raw material description>

[0107] The raw materials of the following examples were all commercially available products unless otherwise specified.

[0108] Preparation Example 1

[0109] The chemical composition of the soft magnetic material of the present preparation example was Sm2Fe 14 B, and was prepared by the following method:

[0110] 1) The single elements of each element were provided according to the chemical composition of the soft magnetic material. The single elements of each element were placed in a quartz crucible, and then the quartz crucible was placed in a medium-frequency induction furnace, and was smelted at 1500℃ under the condition of argon for 10 min to obtain a soft magnetic material master alloy liquid. The soft magnetic material master alloy liquid was cast in a water-cooled copper mold, and was taken out after cooling for 30 min to obtain a soft magnetic material master alloy.

[0111] 2) The soft magnetic material master alloy was placed in a vacuum furnace and heated at a vacuum degree of 3.5 Pa and 1000℃ for 96 h to obtain a soft magnetic material phase alloy.

[0112] 3) The soft magnetic material phase alloy was crushed by a planetary ball mill, and all the powders with a particle size of 100-150 μm were collected by sieving.

[0113] 4) The soft magnetic material powder was mixed with melamine according to a weight ratio of 1:10 to obtain a mixed powder. The mixed powder was placed in an atmosphere furnace, and then nitrogen was filled to an initial pressure of 0.1 MPa. The soft magnetic composite material was prepared by heating at 400℃ for 30 min under the condition of nitrogen without additional nitrogen supply during the heating process.

[0114] The saturation magnetization (Ms) of the soft magnetic composite material prepared in the present preparation example was 137 emu / g.

[0115] Preparation Example 2

[0116] The difference between the present preparation example and Preparation Example 1 is only that the chemical composition of the soft magnetic material of the present preparation example is Sm2(Fe 0.9 Co 0.1 ) 14 B. The Ms of the soft magnetic composite material prepared in the present preparation example is 131 emu / g.

[0117] Preparation Example 3

[0118] The difference between the present preparation example and Preparation Example 1 is only that the chemical composition of the soft magnetic material of the present preparation example is Sm2(Fe

[0119] Preparation Example 4

[0120] The difference between the present preparation example and Preparation Example 2 is only that in step 4), the soft magnetic material powder is mixed with urea according to a weight ratio of 1:10 to obtain a mixed powder. The Ms of the soft magnetic composite material prepared in the present preparation example is 123 emu / g.

[0121] Comparative Preparation Example 1

[0122] The difference between the present comparative preparation example and Preparation Example 1 is only that step 4) is not included, and only the soft magnetic material powder is prepared. The Ms of the soft magnetic composite material prepared in the present comparative preparation example is 125 emu / g.

[0123] Comparative Preparation Example 2

[0124] The difference between the present comparative preparation example and Preparation Example 2 is only that step 4) is not included, and only the soft magnetic material powder is prepared. The Ms of the soft magnetic composite material prepared in the present comparative preparation example is 124 emu / g.

[0125] Comparative Preparation Example 3

[0126] The difference between the present comparative preparation example and Preparation Example 2 is only that in step 4), the heating temperature is 450°C, and the heating time is 60 min. The Ms of the soft magnetic composite material prepared in the present comparative preparation example is 124 emu / g.

[0127] Comparative Preparation Example 4

[0128] The difference between the present comparative preparation example and Preparation Example 3 is only that the chemical composition of the soft magnetic material of the present comparative preparation example is Sm2(Fe 0.6 Co 0.4 ) 14 B. The Ms of the soft magnetic composite material prepared in the present comparative preparation example is 115 emu / g.

[0129] Example 1

[0130] The soft magnetic core ring was prepared from the soft magnetic composite material prepared in Preparation Example 1 according to the following method.

[0131] 1) 10 g of the soft magnetic composite material and 0.3 g of polyurethane were mixed and then placed in 30 mL of acetone, followed by ultrasonic stirring at a frequency of 25 kHz for 10 min, so that the acetone was volatilized and a mixture was obtained.

[0132] 2) The mixture was filled into a ring-shaped mold with a heating function, which had an outer diameter of 12 mm and an inner diameter of 6 mm, and the longitudinal section inside the ring-shaped mold was rectangular, and the inner height of the ring-shaped mold was 5 mm. Then the ring-shaped mold loaded with the mixture was placed in a hydraulic machine, and heated at 300 MPa and 90°C for 10 min to prepare a soft magnetic core ring.

[0133] Examples 2 to 4

[0134] Example 2 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic composite material prepared in Preparation Example 2.

[0135] Example 3 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic composite material prepared in Preparation Example 3.

[0136] Example 4 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic composite material prepared in Preparation Example 4.

[0137] Comparative Examples 1 to 4

[0138] Comparative Example 1 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic material powder prepared in Comparative Preparation Example 1.

[0139] Comparative Example 2 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic material powder prepared in Comparative Preparation Example 2.

[0140] Comparative Example 3 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic composite material prepared in Comparative Preparation Example 3.

[0141] Comparative Example 4 differs from Example 1 only in that the soft magnetic core ring was prepared from the soft magnetic composite material prepared in Comparative Preparation Example 4.

[0142] Experimental Example 1

[0143] The soft magnetic composite material prepared in Preparation Example 1 was subjected to electron probe microanalysis, and the results are shown in Table 1. Figure 1 As can be seen from Table 1, the soft magnetic composite material prepared in Preparation Example 1 has a layer of iron-based nitride (Fe4N) tightly coated on the surface of the soft magnetic material. Figure 1

[0144] ​Experimental Example 2

[0145] The effective permeability (μ) and the power loss per volume (P) of the soft magnetic core rings prepared in Examples 1-4 and Comparative Examples 1-4 were measured at different magnetic field frequencies at room temperature (25℃) and 10 mT magnetic field intensity. e cv The results are shown in Table 1.

[0146] Table 1

[0147]

[0148] As shown in Table 1, the effective permeability of the soft magnetic core ring prepared in the present application is significantly higher than that of the comparative examples. The power loss per volume of the soft magnetic core ring prepared in the present application is significantly lower than that of the comparative examples. This indicates that the insulation performance of the soft magnetic composite material prepared in the present application is significantly superior to that of the comparative examples.

[0149] The present application is not limited to the above-described embodiments, and any modification, improvement, or replacement conceived by those skilled in the art without departing from the essential content of the present application falls within the scope of the present application.​

Claims

1. A method for preparing a soft magnetic composite material, characterized in that: The following steps are involved: 1) providing raw materials according to the chemical composition of the soft magnetic material; melting and rapidly solidifying the raw materials under protective gas conditions to obtain a soft magnetic material master alloy; the chemical composition of the soft magnetic material is RE2(Fe x Co 1-x ) 14 B, wherein RE is selected from at least one of La, Ce, Pr, Nd, Sm, Eu, and Gd; x is the atomic ratio of Fe, 0.7≤x≤1; 2) heating the soft magnetic material master alloy in vacuum at 900-1300° C. to obtain a soft magnetic material phase alloy; 3) preparing the soft magnetic material phase alloy into a powder with a particle size of 75 to 200 μm to obtain a soft magnetic material powder; 4) mixing the soft magnetic material powder and the amino compound in a weight ratio of 1:3 to 15 to obtain a mixed powder; heating the mixed powder under protective gas at 300 to 600° C. to obtain a soft magnetic composite material.

2. The preparation method according to claim 1, characterized in that RE is at least one selected from Pr, Nd, Sm, Eu, and Gd.

3. The preparation method according to claim 1, characterized in that In step 2), the vacuum degree of the heating is below 5 Pa, and the heating time is 80 to 120 hours.

4. The preparation method according to claim 1, characterized in that In step 4), the initial pressure of the protective gas is 0.08 to 0.5 MPa; and the heating time is 15 to 50 minutes.

5. The preparation method according to claim 1, characterized in that In step 4), the amino compound is selected from at least one of C1-C5 monoamines, C2-C6 diamines, aniline and its derivatives, ammonium carbonates or bicarbonates, urea, and melamine.

6. A soft magnetic composite material obtained by the preparation method according to any one of claims 1 to 5, characterized in that: The soft magnetic composite material comprises a soft magnetic material and a coating layer coated on the surface of the soft magnetic material, and the coating layer is Fe4N.

7. Use of the soft magnetic composite material according to claim 6 in preparing soft magnetic devices for electrical equipment.

8. A soft magnetic core ring, characterized in that: The soft magnetic core ring is made from the following raw materials in parts by weight: 100 parts by weight of the soft magnetic composite material according to claim 6 and 1 to 10 parts by weight of a binder.

9. The soft magnetic core ring according to claim 8, characterized in that: The adhesive is selected from at least one of polyurethane, epoxy resin, phenolic resin, polyethylene resin and rubber.

10. A method for preparing the soft magnetic core ring according to claim 8 or 9, characterized in that: The following steps are involved: 1) mixing the soft magnetic composite material and the binder and placing them in an organic solvent, followed by ultrasonic stirring to obtain a mixture; wherein the organic solvent is selected from at least one of acetone, DMF, DMSO, and THF; 2) placing the mixture in a ring-shaped mold and heating it under conditions of 100-500 MPa and 70-150° C. to obtain a soft magnetic core ring.

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