Preparation of a nanocomposite permanent magnet material with high magnetic energy product and coercivity

Abstract

This invention relates to the preparation of a nanocomposite permanent magnet material with high magnetic energy product and coercivity, comprising: preparation of solid epoxy resin, preparation of MnBi alloy ingot, and preparation of Mn... 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets, preparation of nanocrystalline Fe-Ni soft magnetic composite materials, and Mn 55 Bi 45 The preparation of Fe-Ni nanocomposite permanent magnet materials: This invention creatively combines methods such as arc melting, mechanical alloying, high-energy ball milling, and heat treatment. The resulting nanocomposite permanent magnet materials possess high magnetic energy product, excellent coercivity, high saturation magnetization, acid and alkali resistance, and high performance at low cost, making Mn... 55 Bi 45 / Fe-Ni nanocomposite permanent magnet materials have significant advantages in medical device applications within the big health industry.

Description

Technical Field

[0001] This invention relates to a method for preparing a nanocomposite permanent magnet material with high magnetic energy product and coercivity, belonging to the field of new materials technology. Background Technology

[0002] With the continuous development of human society, rare earth permanent magnet materials play an indispensable role in strategic emerging industries such as new energy vehicles, wind power generation, and robotics. However, the excessive consumption of rare earth resources and the sharp rise in prices limit the application of rare earth permanent magnet materials. To address the limitations of rare earth permanent magnet materials, this invention uses MnBi alloy as a raw material. MnBi alloy is a new type of rare earth-free high-performance permanent magnet material with advantages such as high coercivity, moderate saturation magnetization, and magnetic energy product. 55 Bi 45 As a formulation of MnBi alloy, it possesses excellent magnetic properties, while Fe-Ni alloy, as one of the raw materials, is a typical soft magnetic material that also exhibits high saturation magnetization and low coercivity. Furthermore, it possesses a positive coercivity temperature coefficient within a certain range, making it a potential permanent magnet material for medium- and high-temperature applications.

[0003] In the field of nanocomposite permanent magnet materials, the high saturation magnetization of the soft magnetic phase can be combined with the high magnetocrystalline anisotropy of the hard magnetic phase to obtain excellent magnetic properties through the ferromagnetic exchange coupling between the grains of the two phases at the nanoscale. Summary of the Invention

[0004] To address the above problems, this invention provides a method for preparing a nanocomposite permanent magnet material with high magnetic energy product and strong coercivity.

[0005] This invention relates to a method for preparing a nanocomposite permanent magnet material with high magnetic energy product and coercivity, comprising the following steps: step (1) preparation of solid epoxy resin, step (2) preparation of MnBi alloy ingot, step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnet, step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material, step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials;

[0006] Among them, step (4) preparation of nanocrystalline Fe-Ni soft magnetic composite material includes:

[0007] Fe powder and Ni powder were weighed according to a certain ratio and subjected to high-energy ball milling. During the process, alcohol was added to prevent the powder from oxidizing. The ball milling atmosphere was argon. Then, epoxy resin was weighed and dissolved in acetone solution and mixed and stirred. The powder was then added to the solution and mixed and stirred evenly until it was completely evaporated. The mixture was then transferred to a mold and compacted under a certain pressure. Finally, it was annealed at high temperature for a period of time to obtain nanocrystalline Fe-Ni soft magnetic composite material.

[0008] Step (5) Mn 55 Bi 45 The preparation of Fe-Ni nanocomposite permanent magnet materials includes:

[0009] The Mn obtained in step (3) is placed in an inert gas glove box cavity with a certain oxygen content. 55 Bi 45 The alloy hard magnetic phase bonded magnet is uniformly mixed with the nanocrystalline Fe-Ni soft magnetic composite material obtained in step (4), and then ball-milled to produce powder. After ball milling, the powder is collected. After collecting the ball-milled powder, a certain amount of the ball-milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum level is lower than a certain amount, the tube sealing is completed. Finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the process and finally obtain Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0010] Mn prepared by this invention 55 Bi 45 Fe-Ni nanocomposite permanent magnet materials have significant research value and application prospects in the current environment, as they combine Mn... 55 Bi 45 With the advantages of high coercivity and high saturation magnetization of Fe-Ni, it has excellent magnetic properties, which not only helps to alleviate the problem of excessive consumption of rare earth resources, but also has broad application prospects.

[0011] Preferably, step (1) involves the preparation of solid epoxy resin.

[0012] E51 and E20 resins were added to a four-necked flask, and the temperature was raised. The stirring rate was then adjusted, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions. The addition time was controlled, and the reaction was carried out at a constant temperature to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by a mixed solvent (xylene: n-butanol). The solid content was adjusted to obtain the solid epoxy resin.

[0013] Step (2) Preparation of MnBi alloy ingot

[0014] After grinding, high-purity manganese metal raw materials and bismuth metal raw materials are crushed to a suitable size. A certain amount of raw materials are weighed and placed into a copper crucible in an electric arc melting furnace. The furnace cavity is then evacuated and argon gas is introduced to ensure that the melting environment is oxygen-free. The melting is then repeated to obtain a blocky ingot with uniform composition.

[0015] Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0016] The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing. A certain annealing temperature and time were set. When it was taken out, it was water-cooled to room temperature. The ingot was then removed and the oxide scale was polished. It was crushed and ground in a glove box to obtain coarse powder. The powder was then sieved and placed in a ball mill jar. The ball-to-material ratio was set, and oleic acid was added as a surfactant and ethanol as a solvent. Then it was placed in a ball mill and a certain ball milling time was set. After the ball milling was completed, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is then molded and cured at a certain temperature to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0017] Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0018] Fe and Ni powders were weighed according to a specific ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, with a fixed milling speed and time. Subsequently, epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for a certain time. The powder was then added to the solution and stirred evenly until completely evaporated. The mixture was then transferred to a ring mold and compacted under pressure. Finally, it was annealed at high temperature for a period of time to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0019] Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0020] The Mn obtained in step (3) is placed in an inert gas glove box cavity with a certain oxygen content. 55 Bi 45The alloy hard magnetic phase bonded magnet is uniformly mixed with the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4), and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, a certain amount of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than a certain amount, the tube sealing work is completed. Finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the process and finally obtain Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0021] Preferably, step (1) involves the preparation of solid epoxy resin.

[0022] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70-80℃. The stirring speed was then adjusted to 300-400 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 4:1-12:3. The addition time was controlled between 2h and 3h, and the reaction was maintained at this temperature for another 2-3h to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by a mixed solvent (xylene: n-butanol = 3:1-5:2). The solid content was adjusted to 85-90% to obtain the solid epoxy resin.

[0023] The advantages of using this invention are that the solid epoxy resin prepared in this step combines two traditional resins and is modified by adding a chain extender, which improves the shortcomings of low molecular weight epoxy resin. Furthermore, the addition of 1,4-cyclohexanediethanol diglycidyl ether reduces the viscosity of the system, giving the obtained solid epoxy resin the advantage of high toughness. This provides excellent performance for the subsequent preparation steps of composite magnetic materials, and the application prospects of solid epoxy resin are also very broad.

[0024] Preferably, step (2) involves the preparation of the MnBi alloy ingot.

[0025] High-purity manganese and bismuth metal raw materials are ground and then crushed to suitable sizes. The raw materials are weighed according to the nominal composition of Mn:Bi = 55:45-60:50. The raw materials are placed in a copper crucible of an electric arc melting furnace. The furnace cavity is then evacuated to a vacuum level of (3-3.5) × 10⁻⁶. -3After Pa, argon gas is introduced to -(0.05-0.07) Pa to ensure that the melting environment is oxygen-free. Then, the melting is repeated 6-7 times to obtain a blocky ingot with uniform composition.

[0026] The advantages of this invention are that MnBi alloy is selected as the raw material in this step. MnBi alloy is a novel non-rare earth permanent magnet material with high coercivity. Furthermore, the arc melting method is used in this step, which has a relatively fast melting speed and can complete the melting of a large amount of metal material in a short time. This improves the efficiency of preparing MnBi alloy ingots, reduces production costs and shortens the production cycle. At the same time, it helps to obtain MnBi alloy with uniform composition. Alloys with good compositional uniformity have better magnetic and mechanical properties, thereby improving the overall performance of MnBi alloy ingots and laying the groundwork for subsequent steps.

[0027] As a preferred option, step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0028] The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing at a temperature of 563-570K for 24-26 hours. After removal, it was water-cooled to room temperature. The ingot was then removed and its oxide scale was removed and ground. It was then crushed and ground in a glove box to obtain coarse powder, which was sieved through a 100-150 mesh screen. 2-4g of the powder was placed in a ball mill jar with a ball-to-powder ratio of 12.5:1-25:2. Oleic acid (3-3.5% by weight of the powder) was added as a surfactant, and 60-80mL of ethanol was added as a solvent. The mixture was then placed in a ball mill and milled for 0.5-6 hours. After milling, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is then molded and cured at 120-140℃ for 2-3 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0029] The advantage of using this invention is that high-energy ball milling and annealing are employed in this step. High-energy ball milling can make Mn 55 Bi 45 The alloy achieves optimal magnetic properties in the shortest time, giving it excellent coercivity, which improves the efficiency of this invention. Annealing treatment can effectively improve the Mn... 55 Bi 45The alloy's saturation magnetization gives it excellent magnetic properties and provides a superior performance foundation for the subsequent preparation of composite permanent magnet materials.

[0030] Preferably, step (4) involves the preparation of nanocrystalline Fe-Ni soft magnetic composite materials.

[0031] Fe powder and Ni powder were weighed according to a ratio of 100:5-200:10 and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3-4% alcohol added during the process to prevent powder oxidation. The ball milling atmosphere was argon, with a fixed milling speed of 300-350 r / min and a milling time of 20-50 h. Subsequently, 2-3% (by mass) of epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for 30-45 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400-450 MPa. Finally, it was annealed at 550-700℃ for 3-4 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0032] The advantages of this invention are that this step employs a planetary high-energy ball milling method. This complex motion trajectory greatly enhances the impact force and grinding effect of the grinding media on the material, enabling the raw materials to be efficiently refined to the nanoscale. In addition, the high-intensity mechanical force can ensure the full mixing of different component raw materials. In the preparation of Fe-Ni soft magnetic composite materials, this efficient refinement and mixing can make Fe and Ni elements uniformly distributed at the nanoscale, thereby optimizing the magnetic properties of the material and giving the Fe-Ni soft magnetic composite material the advantages of high magnetic energy product and good coercivity.

[0033] As a preferred option, step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0034] The Mn obtained in step (3) was placed in an inert gas glove box cavity with an oxygen content controlled at 6-8 ppm. 55 Bi 45The alloy hard magnetic phase bonded magnet is uniformly mixed with the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4), and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains Ar gas, which can protect the powder material and reduce oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4-0.5g of the ball milled powder is placed in a quartz glass tube, installed on the tube sealing machine and vacuumed. When the vacuum degree is lower than (2-3)×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0035] The advantage of this invention is that it can achieve the production of Mn through planetary high-energy ball milling. 55 Bi 45 Uniform composite of Fe-Ni at the nanoscale, while Mn 55 Bi 45 As a hard magnetic phase, Fe-Ni, as a soft magnetic phase, can generate strong exchange coupling when combined at the nanoscale. This exchange coupling helps improve the coercivity and energy product of the composite material, thereby enhancing its permanent magnetic properties. This results in the final Mn... 55 Bi 45 / Fe-Ni nanocomposite permanent magnet materials combine the advantages of both, resulting in high magnetic energy product and strong coercivity. These advantages make this material have broad application prospects and important research value in the field of permanent magnet materials.

[0036] In summary, the present invention has the following beneficial effects:

[0037] 1. The advantages of using this invention are that the solid epoxy resin prepared in this step combines two traditional resins and is modified by adding a chain extender, which improves the shortcomings of low molecular weight epoxy resin. In addition, the addition of 1,4-cyclohexanediethanol diglycidyl ether reduces the viscosity of the system, giving the obtained solid epoxy resin the advantage of high toughness. This provides excellent performance for the subsequent preparation of composite magnetic materials. At the same time, the application prospects of solid epoxy resin are also very broad.

[0038] 2. The advantages of using this invention are that MnBi alloy is selected as the raw material in this step. MnBi alloy is a new type of non-rare earth permanent magnet material with high coercivity. Furthermore, the electric arc melting method is used in this step. This method has a relatively fast melting speed and can complete the melting of a large amount of metal material in a short time. This improves the efficiency of preparing MnBi alloy ingots, reduces production costs and shortens the production cycle. At the same time, it helps to obtain MnBi alloy with uniform composition. Alloys with good compositional uniformity have better magnetic and mechanical properties, thereby improving the overall performance of MnBi alloy ingots and laying the groundwork for subsequent steps.

[0039] 3. The advantage of using this invention is that high-energy ball milling and annealing are employed in this step. High-energy ball milling can make Mn... 55 Bi 45 The alloy achieves optimal magnetic properties in the shortest time, giving it excellent coercivity, which improves the efficiency of this invention. Annealing treatment can effectively improve the Mn... 55 Bi 45 The alloy's saturation magnetization gives it excellent magnetic properties and provides a superior performance foundation for the subsequent preparation of composite permanent magnet materials.

[0040] 4. The advantages of using this invention are that this step employs a planetary high-energy ball milling method. This complex motion trajectory greatly enhances the impact force and grinding effect of the grinding media on the material, enabling the raw materials to be efficiently refined to the nanoscale. In addition, the high-intensity mechanical force can also ensure the full mixing of different component raw materials. In the preparation of Fe-Ni soft magnetic composite materials, this efficient refinement and mixing can make Fe and Ni elements uniformly distributed at the nanoscale, thereby optimizing the magnetic properties of the material and giving the Fe-Ni soft magnetic composite material the advantages of high magnetic energy product and good coercivity.

[0041] 5. The advantage of using this invention is that it can achieve the production of Mn through planetary high-energy ball milling. 55 Bi 45 Uniform composite of Fe-Ni at the nanoscale, while Mn 55 Bi 45 As a hard magnetic phase, Fe-Ni, as a soft magnetic phase, can generate strong exchange coupling when combined at the nanoscale. This exchange coupling helps improve the coercivity and energy product of the composite material, thereby enhancing its permanent magnetic properties. This results in the final Mn... 55 Bi 45 / Fe-Ni nanocomposite permanent magnet materials combine the advantages of both, resulting in high magnetic energy product and strong coercivity. These advantages make this material have broad application prospects and important research value in the field of permanent magnet materials. Attached Figure Description

[0042] Figure 1 This is a flowchart illustrating the preparation process of a nanocomposite permanent magnet material with high magnetic energy product and coercivity according to the present invention. Detailed Implementation

[0043] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention.

[0044] Unless otherwise specified, the techniques used in the embodiments are conventional techniques well known to those skilled in the art. Furthermore, all component raw materials used in the embodiments are known commercially available products.

[0045] Example 1

[0046] Step (1) Preparation of solid epoxy resin

[0047] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70°C. The stirring speed was then adjusted to 300 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 4:1 over a period of 2 hours. The reaction was then maintained at this temperature for another 2 hours to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, along with a mixed solvent (xylene: n-butanol = 3:1) to adjust the solid content to 85%, thus obtaining the solid epoxy resin.

[0048] Step (2) Preparation of MnBi alloy ingot

[0049] High-purity manganese and bismuth metal raw materials are ground and then crushed to suitable sizes. The raw materials are weighed according to the nominal composition of Mn:Bi = 55:45. The raw materials are placed in a copper crucible of an electric arc melting furnace, and then a vacuum is drawn into the furnace cavity to a vacuum level of 3 × 10⁻⁶. -3 After Pa, argon gas is introduced to -0.05 Pa to ensure that the melting environment is oxygen-free. Then, the melting is repeated 6 times to obtain a blocky ingot with uniform composition.

[0050] Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0051] The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing at 563K for 24 hours. After removal, it was cooled to room temperature with water. The ingot was then removed and the oxide scale was removed and ground. It was crushed and ground in a glove box to obtain coarse powder, which was then sieved through a 100-mesh sieve. Two powders were placed in a ball mill jar with a ball-to-powder ratio of 12.5:1. Oleic acid (3% by weight of powder) was added as a surfactant and 60 mL of ethanol as a solvent. The mixture was then placed in a ball mill and the milling time was set to 2 hours. After milling, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is molded and then cured at 120°C for 2 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0052] Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0053] Fe powder and Ni powder were weighed in a 100:5 ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, the milling speed was fixed at 300 r / min, and the milling time was 20 h. Subsequently, 2% (by mass) of epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for 30 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400 MPa. Finally, it was annealed at 650℃ for 3 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0054] Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0055] The Mn obtained in step (3) was placed in an inert gas glove box chamber with an oxygen content controlled at 8 ppm. 55 Bi 45The alloy hard magnetic phase bonded magnet and the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4) are uniformly mixed and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4g of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than 2×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0056] Example 2

[0057] Step (1) Preparation of solid epoxy resin

[0058] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70°C. The stirring speed was then adjusted to 300 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 6:1 over a period of 2 hours. The reaction was then maintained at this temperature for another 2 hours to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, along with a mixed solvent (xylene: n-butanol = 3:1) to adjust the solid content to 85%, thus obtaining the solid epoxy resin.

[0059] Step (2) Preparation of MnBi alloy ingot

[0060] High-purity manganese and bismuth metal raw materials are ground and then crushed to suitable sizes. The raw materials are weighed according to the nominal composition of Mn:Bi = 55:45. The raw materials are placed in a copper crucible of an electric arc melting furnace, and then a vacuum is drawn into the furnace cavity to a vacuum level of 3 × 10⁻⁶. -3 After Pa, argon gas is introduced to -0.05 Pa to ensure that the melting environment is oxygen-free. Then, the melting is repeated 6 times to obtain a blocky ingot with uniform composition.

[0061] Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0062] The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing at 563K for 24 hours. After removal, it was cooled to room temperature with water. The ingot was then removed and the oxide scale was removed and ground. The powder was crushed and ground in a glove box to obtain coarse powder, which was then sieved through a 100-mesh sieve. Two powders were placed in a ball mill jar with a ball-to-powder ratio of 12.5:1. Oleic acid (3% by weight of powder) was added as a surfactant and 60 mL of ethanol as a solvent. The mixture was then placed in a ball mill and the milling time was set to 0.5 hours. After the milling was completed, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is molded and then cured at 120°C for 2 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0063] Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0064] Fe powder and Ni powder were weighed in a 100:5 ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, the milling speed was fixed at 300 r / min, and the milling time was 20 h. Subsequently, 2% (by mass) of epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for 30 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400 MPa. Finally, it was annealed at 600℃ for 3 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0065] Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0066] The Mn obtained in step (3) was placed in an inert gas glove box chamber with an oxygen content controlled at 8 ppm. 55 Bi 45The alloy hard magnetic phase bonded magnet and the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4) are uniformly mixed and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4g of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than 2×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0067] Example 3

[0068] Step (1) Preparation of solid epoxy resin

[0069] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70°C. The stirring speed was then adjusted to 300 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 7:1. The addition time was controlled at 2 h, and the reaction was maintained at this temperature for another 2 h to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by a mixed solvent (xylene: n-butanol = 3:1). The solid content was adjusted to 85% to obtain the solid epoxy resin.

[0070] Step (2) Preparation of MnBi alloy ingot

[0071] High-purity manganese and bismuth metal raw materials are ground and then crushed to suitable sizes. The raw materials are weighed according to the nominal composition of Mn:Bi = 55:45. The raw materials are placed in a copper crucible of an electric arc melting furnace, and then a vacuum is drawn into the furnace cavity to a vacuum level of 3 × 10⁻⁶. -3 After Pa, argon gas is introduced to -0.05 Pa to ensure that the melting environment is oxygen-free. Then, the melting is repeated 6 times to obtain a blocky ingot with uniform composition.

[0072] Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0073] The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing at 563K for 24 hours. After removal, it was cooled to room temperature with water. The ingot was then removed and its oxide scale was removed and ground. It was crushed and ground in a glove box to obtain coarse powder, which was then sieved through a 100-mesh sieve. Two powders were placed in a ball mill jar with a ball-to-powder ratio of 12.5:1. Oleic acid (3% by weight of powder) was added as a surfactant and 60 mL of ethanol as a solvent. The mixture was then placed in a ball mill and the milling time was set to 1 hour. After milling, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is molded and then cured at 120°C for 2 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0074] Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0075] Fe powder and Ni powder were weighed in a 100:5 ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, the milling speed was fixed at 300 r / min, and the milling time was 20 h. Subsequently, 2% (by mass) of epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for 30 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400 MPa. Finally, it was annealed at 625℃ for 3 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0076] Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0077] The Mn obtained in step (3) was placed in an inert gas glove box chamber with an oxygen content controlled at 8 ppm. 55 Bi 45The alloy hard magnetic phase bonded magnet and the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4) are uniformly mixed and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4g of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than 2×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0078] Example 4

[0079] Step (1) Preparation of solid epoxy resin

[0080] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70°C. The stirring speed was then adjusted to 300 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 8:1. The addition time was controlled at 2 h, and the reaction was maintained at this temperature for another 2 h to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by a mixed solvent (xylene: n-butanol = 3:1). The solid content was adjusted to 85% to obtain the solid epoxy resin.

[0081] Step (2) Preparation of MnBi alloy ingot

[0082] High-purity manganese and bismuth metal raw materials are ground and then crushed to suitable sizes. The raw materials are weighed according to the nominal composition of Mn:Bi = 55:45. The raw materials are placed in a copper crucible of an electric arc melting furnace, and then a vacuum is drawn into the furnace cavity to a vacuum level of 3 × 10⁻⁶. -3 After Pa, argon gas is introduced to -0.05 Pa to ensure that the melting environment is oxygen-free. Then, the melting is repeated 6 times to obtain a blocky ingot with uniform composition.

[0083] Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0084] The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing at 563K for 24 hours. After removal, it was cooled to room temperature with water. The ingot was then removed and its oxide scale was removed and ground. It was crushed and ground in a glove box to obtain coarse powder, which was then sieved through a 100-mesh sieve. Two powders were placed in a ball mill jar with a ball-to-powder ratio of 12.5:1. Oleic acid (3% by weight of powder) was added as a surfactant and 60 mL of ethanol as a solvent. The jar was then placed in a ball mill and the milling time was set to 3 hours. After the milling was completed, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is molded and then cured at 120°C for 2 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0085] Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0086] Fe powder and Ni powder were weighed in a 100:5 ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, the milling speed was fixed at 300 r / min, and the milling time was 20 h. Subsequently, 2% (by mass) of epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for 30 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400 MPa. Finally, it was annealed at 700℃ for 3 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0087] Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0088] The Mn obtained in step (3) was placed in an inert gas glove box chamber with an oxygen content controlled at 8 ppm. 55 Bi 45The alloy hard magnetic phase bonded magnet and the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4) are uniformly mixed and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4g of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than 2×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0089] Comparative Example 1

[0090] Step (1) Preparation of solid epoxy resin

[0091] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70°C. The stirring speed was then adjusted to 300 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 9:1. The addition time was controlled at 2 h, and the reaction was maintained at this temperature for another 2 h to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by a mixed solvent (xylene: n-butanol = 3:1). The solid content was adjusted to 85% to obtain solid epoxy resin.

[0092] Step (2) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0093] MnBi alloy ingots were annealed in a tubular vacuum annealing furnace at 563 K for 24 hours. After removal, the ingots were water-cooled to room temperature. The oxide scale was removed, and the ingots were then crushed and ground in a glove box to obtain coarse powder, which was sieved through a 100-mesh sieve. Two portions of the powder were placed in a ball mill jar at a ball-to-powder ratio of 12.5:1, with 3% (by weight) of oleic acid as a surfactant and 60 mL of ethanol as a solvent. The jar was then placed in a ball mill and milled for 4 hours. After milling, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic MnBi alloys. 55 Bi 45For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is molded and then cured at 120°C for 2 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0094] Step (3) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0095] Fe powder and Ni powder were weighed in a 100:5 ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, the milling speed was fixed at 300 r / min, and the milling time was 20 h. Subsequently, 2% (by mass) of epoxy resin was dissolved in acetone solution and stirred for 30 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400 MPa. Finally, it was annealed at 575℃ for 3 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0096] Step (4) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0097] The Mn obtained in step (2) was placed in an inert gas glove box chamber with an oxygen content controlled at 8 ppm. 55 Bi 45 The alloy hard magnetic phase bonded magnet and the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (3) are uniformly mixed and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4g of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than 2×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0098] Comparative Example 2

[0099] Step (1) Preparation of solid epoxy resin

[0100] E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70°C. The stirring speed was then adjusted to 300 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 10:1 over a period of 2 hours. The reaction was then maintained at this temperature for another 2 hours to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, along with a mixed solvent (xylene: n-butanol = 3:1), and the solid content was adjusted to 85% to obtain the solid epoxy resin.

[0101] Step (2) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets

[0102] MnBi alloy ingots were annealed in a tubular vacuum annealing furnace at 563 K for 24 hours. After removal, the ingots were water-cooled to room temperature. The oxide scale was removed, and the ingots were then crushed and ground in a glove box to obtain coarse powder, which was sieved through a 100-mesh sieve. Two portions of the powder were placed in a ball mill jar at a ball-to-powder ratio of 12.5:1, with 3% (by weight) of oleic acid as a surfactant and 60 mL of ethanol as a solvent. The jar was then placed in a ball mill and milled for 5 hours. After milling, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic MnBi alloys. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is molded and then cured at 120°C for 2 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets;

[0103] Step (3) Preparation of nanocrystalline Fe-Ni soft magnetic composite material

[0104] Fe powder and Ni powder were weighed in a 100:5 ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, the milling speed was fixed at 300 r / min, and the milling time was 20 h. Subsequently, 2% (by mass) of epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for 30 min. The powder was then added to the solution and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400 MPa. Finally, it was annealed at 550℃ for 3 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

[0105] Step (4) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials

[0106] The Mn obtained in step (2) was placed in an inert gas glove box cavity with an oxygen content controlled at 7 ppm. 55 Bi 45 The alloy hard magnetic phase bonded magnet and the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (3) are uniformly mixed and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, about 0.4g of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than 2×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

[0107] Comparison of detection experiments:

[0108] The nanocomposite permanent magnet materials obtained in Examples 1 to 4 and comparative products 1 and 2 were tested using the following specific testing methods:

[0109] Viscosity testing

[0110] Viscosity testing of epoxy resin systems: The viscosity of different epoxy resins was tested using a digital viscometer. The temperature was set at 25℃, the rotor within the measurement range was selected, the digital viscometer was adjusted to maintain a horizontal position, and various data were set. The viscosity test of each epoxy resin sample was performed 3 times, and the average value of the 3 tests was taken.

[0111] Magnetic property analysis

[0112] Annealed Mn 55 Bi 45 Mn was prepared by high-energy ball milling for 0.5 hours, 1 hour, 2 hours, 4 hours, 5 hours, and 6 hours after crushing, grinding, and sieving of alloy ingots. 55 Bi 45 This patent uses a soft magnetic AC testing device to test the Mn alloy. 55 Bi 45The magnetic properties of the Fe-Ni nanocomposite permanent magnet material were analyzed and tested, and the saturation magnetization and coercivity of the sample were analyzed separately. The results are shown in the table below.

[0113] Table 1 Viscosity Detection

[0114]

[0115] As shown in Table 1, Example 1 exhibits the best viscosity performance, while Comparative Example 2 is inferior. In Example 1, the viscosity of the epoxy resin reaches 42,000 mPa·s, while in Comparative Example 2 it is only 24,000 mPa·s. This indicates that the viscosity of this epoxy resin decreases with increasing mass of raw material E51 resin. The greater the mass of raw material E51 resin, the lower the viscosity of this epoxy resin. Higher viscosity indicates better toughness of this epoxy resin, and improved toughness plays an important role in the subsequent composite of magnetic materials, providing a foundation for excellent performance.

[0116] Table 2 Coercivity Test

[0117]

[0118] As shown in Table 2, Example 1 exhibits the best performance. Its intrinsic coercivity reaches 13.4 Oe, the highest, while Comparative Example 2 is inferior, with an intrinsic coercivity of 5.1. This indicates that intrinsic coercivity increases with increasing ball milling time, but peaks at 2 hours and then decreases with further increases in ball milling time. Therefore, a ball milling time of 2 hours is optimal in this invention, maximizing the optimal performance of Mn. 55 Bi 45 The intrinsic coercivity of alloy hard magnetic phase bonded magnets is the best.

[0119] Table 3 Magnetic Property Detection

[0120]

[0121] As shown in Table 3, Example 1 exhibits the best performance, while Comparative Example 2 performs worse. Example 1 has a saturation magnetization as high as 33.1 Am. 2 / kg, compared to 20.1 Am in Comparative Example 2 2 / kg, which shows that the saturation magnetization increases with the increase of annealing temperature. The saturation magnetization reaches its peak when the annealing temperature reaches 650℃, and then weakens with the increase of annealing temperature. In summary, the nanocrystalline Fe-Ni soft magnetic composite material has the best saturation magnetization and the best magnetic properties when the annealing temperature is 650℃.

[0122] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for preparing a nanocomposite permanent magnet material with high magnetic energy product and strong coercivity, characterized in that, include: Step (1) Preparation of solid epoxy resin, Step (2) Preparation of MnBi alloy ingot, Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnet, step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material, step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials; Among them, step (4) preparation of nanocrystalline Fe-Ni soft magnetic composite material includes: Fe powder and Ni powder are weighed according to a certain measurement ratio and subjected to high-energy ball milling. During the process, alcohol is added to prevent the powder from oxidizing. The ball milling atmosphere is argon. Then, epoxy resin is weighed and dissolved in acetone solution and mixed and stirred. The above powder is added to the solution and mixed and stirred evenly until it is completely evaporated. Then, it is compacted and molded under a certain pressure. Finally, it is annealed at high temperature for a period of time to obtain nanocrystalline Fe-Ni soft magnetic composite material. Step (5) Mn 55 Bi 45 The preparation of Fe-Ni nanocomposite permanent magnet materials includes: The Mn obtained in step (3) 55 Bi 45 The alloy hard magnetic phase bonded magnet is uniformly mixed with the nanocrystalline Fe-Ni soft magnetic composite material obtained in step (4), and then ball-milled to produce powder. After ball milling, the powder is collected. After collecting the ball-milled powder, a certain amount of the ball-milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum level is lower than a certain amount, the tube sealing is completed. Finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the process and finally obtain Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

2. The preparation method of the nanocomposite permanent magnet material with high magnetic energy product and coercivity according to claim 1, characterized in that: Step (1) Preparation of solid epoxy resin E51 resin and E20 resin were added to a four-necked flask, the temperature was raised, the stirring rate was adjusted, and under these conditions, the chain extender polyaspartic acid ester resin was added dropwise, the dropwise time was controlled, and the reaction was carried out at the temperature to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by the mixed solvents xylene and n-butanol, and the solid content was adjusted to obtain solid epoxy resin. Step (2) Preparation of MnBi alloy ingot High-purity manganese and bismuth metal raw materials are ground and then crushed to a suitable size. A certain amount of raw materials are weighed and placed into a copper crucible in an electric arc melting furnace. The furnace cavity is then evacuated and filled with argon gas to ensure that the melting environment is oxygen-free. The melting is then repeated to obtain a blocky ingot with uniform composition. Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing. A certain annealing temperature and time were set. When it was taken out, it was water-cooled to room temperature. The ingot was then removed and the oxide scale was polished. It was crushed and ground in a glove box to obtain coarse powder. The powder was then sieved and placed in a ball mill jar. The ball-to-material ratio was set, and oleic acid was added as a surfactant and ethanol as a solvent. Then it was placed in a ball mill and a certain ball milling time was set. After the ball milling was completed, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is then molded and cured at a certain temperature to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets; Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material Fe and Ni powders were weighed according to a specific ratio and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, with a fixed milling speed and time. Subsequently, epoxy resin was weighed and dissolved in acetone solution, and the mixture was stirred for a certain time. The powder was then added to the solution and stirred evenly until completely evaporated. The mixture was then transferred to a ring mold and compacted under pressure. Finally, it was annealed at high temperature for a period of time to obtain the nanocrystalline Fe-Ni soft magnetic composite material. Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials The Mn obtained in step (3) is placed in an inert gas glove box cavity with a certain oxygen content. 55 Bi 45 The alloy hard magnetic phase bonded magnet is uniformly mixed with the nanocrystalline Fe-Ni soft magnetic composite material prepared in step (4), and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains a certain amount of Ar gas, which can play a role in protecting the powder material and reducing oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the experimental conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, a certain amount of the ball milled powder is placed in a quartz glass tube and installed on a tube sealing machine for vacuuming. When the vacuum degree is lower than a certain amount, the tube sealing work is completed. Finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the process and finally obtain Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

3. The preparation of the nanocomposite permanent magnet material with high magnetic energy product and coercivity according to claim 2, characterized in that: Step (1) Preparation of solid epoxy resin E51 and E20 resins were added to a four-necked flask, and the temperature was raised to 70-80℃. The stirring speed was then adjusted to 300-400 r / min, and the chain extender polyaspartic acid ester resin was added dropwise under these conditions at a ratio of 4:1-12:

3. The addition time was controlled between 2-3 hours, and the reaction was maintained at this temperature for another 2-3 hours to obtain the chain-extended epoxy resin. Then, 1,4-cyclohexanediethanol diglycidyl ether was added, followed by a mixed solvent (xylene: n-butanol = 3:1-5:2). The solid content was adjusted to 85-90% to obtain the solid epoxy resin.

4. The preparation of the nanocomposite permanent magnet material with high magnetic energy product and coercivity according to claim 3, characterized in that: Step (2) Preparation of MnBi alloy ingot High-purity manganese and bismuth metal raw materials are ground and then crushed to suitable sizes. The raw materials are weighed according to the nominal composition of Mn:Bi = 55:45-60:

50. The raw materials are placed in a copper crucible of an electric arc melting furnace. The furnace cavity is then evacuated to a vacuum level of (3-3.5) × 10⁻⁶. -3 After Pa, argon gas is introduced to -(0.05-0.07) Pa to ensure that the melting environment is oxygen-free. Then, the melting is repeated 6-7 times to obtain a blocky ingot with uniform composition.

5. The preparation of the nanocomposite permanent magnet material with high magnetic energy product and coercivity according to claim 4, characterized in that: Step (3) Mn 55 Bi 45 Preparation of alloy hard magnetic phase bonded magnets The MnBi alloy ingot obtained in step (2) above was placed in a tubular vacuum annealing furnace for annealing at a temperature of 563-570K for 24-26 hours. After removal, it was water-cooled to room temperature. The ingot was then removed and its oxide scale was removed and ground. It was then crushed and ground in a glove box to obtain coarse powder, which was sieved through a 100-150 mesh screen. 2-4g of the powder was placed in a ball mill jar with a ball-to-powder ratio of 12.5:1-25:

2. Oleic acid (3-3.5% by weight of the powder) was added as a surfactant, and 60-80mL of ethanol was added as a solvent. The mixture was then placed in a ball mill and milled for 0.5-6 hours. After milling, the slurry was washed with anhydrous ethanol and then mixed with paraffin to prepare anisotropic Mn. 55 Bi 45 For alloy magnetic powder, acetone is added to the epoxy resin obtained in step (1), and after it is completely melted, it is added to the magnetic powder. The mixture is stirred with a stirrer. As the stirring proceeds, the acetone gradually evaporates, and the epoxy resin and magnetic powder are evenly mixed together. The magnetic powder mixed with epoxy resin is then molded and cured at 120-140℃ for 2-3 hours to obtain Mn. 55 Bi 45 Alloy hard magnetic phase bonded magnets.

6. The preparation of the nanocomposite permanent magnet material with high magnetic energy product and coercivity according to claim 5, characterized in that: Step (4) Preparation of nanocrystalline Fe-Ni soft magnetic composite material Fe powder and Ni powder were weighed in a ratio of 100:5-200:10 and added to a stainless steel ball mill jar. High-energy ball milling was performed using a planetary high-energy ball mill, with 3-4% alcohol added to prevent powder oxidation. The ball milling atmosphere was argon, with a fixed milling speed of 300-350 r / min and a milling time of 20-50 h. Subsequently, 2-3% (by mass) of epoxy resin was dissolved in acetone solution and mixed and stirred for 30-45 min. The powder was then added to the solution and mixed and stirred until completely evaporated. The mixture was then transferred to a ring mold and compacted under a pressure of 400-450 MPa. Finally, the mixture was annealed at 550-700℃ for 3-4 h to obtain the nanocrystalline Fe-Ni soft magnetic composite material.

7. The preparation of the nanocomposite permanent magnet material with high magnetic energy product and coercivity according to claim 6, characterized in that: Step (5) Mn 55 Bi 45 Preparation of Fe-Ni nanocomposite permanent magnet materials The Mn obtained in step (3) was placed in an inert gas glove box cavity with an oxygen content controlled at 6-8 ppm. 55 Bi 45 The alloy hard magnetic phase bonded magnet is uniformly mixed with the nanocrystalline Fe-Ni soft magnetic composite material obtained in step (4), and then placed in a high-energy ball mill jar with steel balls. After that, the ball mill cover is tightened and taken out from the inert gas glove box. At this time, the ball mill jar contains Ar gas, which can protect the powder material and reduce oxidation during subsequent grinding. The tightened ball mill jar is taken out from the inert gas glove box and installed and fixed in the high-energy ball mill. Ball milling is carried out according to the conditions. After ball milling, the powder is collected in the inert gas glove box. After collecting the ball milled powder, 0.4-0.5g of the ball milled powder is placed in a quartz glass tube, installed on the tube sealing machine and vacuumed. When the vacuum degree is lower than (2-3)×10 -4 At Pa, the tube sealing process is completed; finally, the vacuum-sealed quartz glass tube is placed in a box-type resistance furnace to complete the final process, yielding Mn. 55 Bi 45 / Fe-Ni nanocomposite permanent magnet material.

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