A method for preparing anisotropic samarium iron nitrogen magnetic powder

Abstract

This invention discloses a method for preparing anisotropic samarium iron nitrogen magnetic powder, belonging to the field of magnetic materials technology. The method includes the following steps: preparing Sm and Fe according to the designed composition, melting them to obtain samarium iron alloy molten steel; casting the samarium iron alloy molten steel onto a cooling roller to obtain iron-samarium alloy sheets; placing the iron-samarium alloy sheets in a vacuum heat treatment furnace for homogenization treatment; cooling the homogenized alloy sheets to 200-300°C; introducing hydrogen into the furnace under vacuum, controlling the absolute pressure of hydrogen at 0.05-0.1 MPa, and hydrogenating for 2 hours; after hydrogenation, raising the temperature to 400°C, filling with nitrogen to 0.5 MPa, raising the temperature to 530°C, and then lowering the furnace temperature to room temperature to obtain the anisotropic samarium iron nitrogen magnetic powder. This invention provides a method for preparing samarium iron nitrogen magnetic powder, which has the advantages of simple preparation process, low energy consumption, high production efficiency, small magnetic powder particle size, high magnetic properties, and good magnetic crystal anisotropy.

Description

Technical Field

[0001] This invention belongs to the field of magnetic materials technology, specifically relating to a method for preparing anisotropic samarium iron nitrogen magnetic powder. Background Technology

[0002] In the field of magnetic materials, samarium iron nitrogen (Sm2Fe) 17 N x Magnetic powder is an important functional material widely used in various magnetic components, such as motors, magnetic data cables, and induction magnetic rings. The main methods for preparing samarium iron nitrogen magnetic powder include the HDDR (hydrogenation-disproportionation-dehydrogenation-rehydrogenation) method, melt rapid quenching method, and reduction diffusion method.

[0003] In the field of powder metallurgy, the particle size, shape, and magnetic properties of magnetic powder are key factors affecting the performance of magnetic components. In the field of materials processing, the preparation process of magnetic powder needs to consider factors such as energy consumption, production efficiency, and environmental protection.

[0004] The HDDR method is a traditional preparation method that induces a phase transformation in samarium-iron alloys through hydrogenation, disproportionation, dehydrogenation, and re-hydrogenation to form samarium-iron-nitrogen magnetic powder with high magnetic anisotropy. For example, Chinese patent application CN118969491A discloses a method for preparing isotropic samarium-iron-nitrogen magnetic powder, including the following steps: [The text abruptly ends here, likely due to an incomplete sentence or missing information.] 17 The following steps are performed: Sm and Fe are weighed in excess (5%–10%) and smelted and rapidly solidified to produce samarium-iron alloy sheets. The samarium-iron alloy sheets are then crushed to prepare powdered samarium-iron alloy. The powdered samarium-iron alloy undergoes high-temperature nitriding (HDDR) treatment to obtain isotropic alloy blocks. These isotropic alloy blocks are crushed and aged to obtain isotropic alloy powder. The aged isotropic alloy powder is then subjected to high-temperature nitriding to obtain Sm₂Fe. 17 The isotropic magnetic powder prepared from N3 has both high magnetic energy product and coercivity.

[0005] For example, Chinese patent application CN117912795A provides a Sm2Fe 17 The in-situ multi-stage preparation method of N3 magnetic powder relates to the field of magnetic material preparation technology. It includes the following steps: (1) obtaining samarium iron alloy sheets by induction melting and rapid solidification under a protective atmosphere; (2) adding the samarium iron alloy sheets with good oxidation resistance to a reaction vessel, and using the principle of hydrogen disproportionation decomposition, crushing the samarium iron alloy sheets into powder through hydrogen filling and dehydrogenation; (3) filling the reaction vessel with high-pressure nitrogen gas to perform in-situ nitriding treatment on the samarium iron alloy powder to obtain Sm2Fe. 17 N3 magnetic powder.

[0006] Existing methods for preparing samarium iron nitrogen magnetic powder have several problems. The HDDR method is complex, energy-intensive, and has low production efficiency, making it unsuitable for large-scale production. The high-pressure hydrogen pyrolysis method requires high-pressure equipment, involves large investment, and is complex to operate, also making it unsuitable for large-scale production. Therefore, developing a method for preparing samarium iron nitrogen magnetic powder that is simple in process, low in energy consumption, highly efficient, produces small-particle-size magnetic powder with high magnetic properties and good magnetocrystalline anisotropy is the main challenge facing the technology at present. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing anisotropic samarium iron nitrogen magnetic powder, so as to solve the problems of high energy consumption and complex process in the preparation of samarium iron nitrogen magnetic powder in the prior art.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A method for preparing anisotropic samarium iron nitrogen magnetic powder includes the following steps:

[0010] Step 1: Prepare Sm and Fe, melt them to obtain samarium iron alloy steel liquid;

[0011] Step 2: Pour the molten samarium-iron alloy steel onto the cooling roller to obtain samarium-iron alloy sheets;

[0012] Step 3: Place the iron-samarium alloy sheet in a vacuum heat treatment furnace for homogenization treatment. After homogenization treatment, cool the alloy sheet to 200-300°C. In a vacuum environment, introduce hydrogen into the furnace. The absolute pressure of the hydrogen is controlled at 0.05-0.1 MPa. Hydrogenation treatment is carried out for 2 hours.

[0013] Step 4: After hydrogenation, the temperature is raised to 400°C, nitrogen gas is introduced to 0.5 MPa, the temperature is raised to 530°C, and then the furnace temperature is lowered to room temperature to obtain the anisotropic samarium iron nitrogen magnetic powder.

[0014] Furthermore, the specific operation of step 1 is as follows:

[0015] Prepare Sm and Fe. Add 50% of the total mass of Sm and all of the Fe to the melting furnace. Evacuate the inside of the melting furnace and heat it until Sm and Fe melt to a liquid state. Then add the remaining Sm. After it is completely melted, continue melting for 40 minutes to obtain samarium-iron alloy steel liquid.

[0016] This invention employs a two-stage feeding method for rapid solidification and smelting, followed by homogenization treatment to obtain Sm2Fe. 17 Unlike the complex processes of HDDR and high-voltage methods, the alloy sheet prepared in this invention has a simpler preparation process, lower energy consumption, higher production efficiency, and is suitable for large-scale production.

[0017] Furthermore, in step 4, the heating rate during the process of heating to 400℃ is 10℃ / min.

[0018] Furthermore, in step 1, the atomic percentages of Sm and Fe are Sm 2.2 Fe 17 Then, the atomic percentages were converted to mass percentages; among which, the theoretical alloy composition Sm2Fe 17 In comparison, Sm was 10% excessive.

[0019] Furthermore, in step 1, Sm is samarium particles with a particle size of 1 to 100 mm and a purity of ≥99.9%.

[0020] Furthermore, in step 1, Fe is an iron rod with a purity of ≥99%.

[0021] Furthermore, in step 1, the internal pressure of the smelting furnace is ≤10Pa.

[0022] Furthermore, in step 2, the cooling roller rotation speed is 2 r / min.

[0023] Furthermore, the homogenization pressure in step 3 is 1×10⁻⁶. -2 Pa, temperature 1000℃, time 8h.

[0024] Furthermore, in step 4, the average particle size of the anisotropic samarium iron nitrogen magnetic powder is 20 μm.

[0025] Furthermore, the method for preparing anisotropic samarium iron nitrogen magnetic powder also includes a testing step for the anisotropic samarium iron nitrogen magnetic powder, the testing step being as follows:

[0026] The anisotropic samarium iron nitrogen magnetic powder and polyvinyl chloride (CPE) were mixed at a mass ratio of 10:90. The mixture was then placed in a calender and calendered at a calendering temperature of 180°C, a calendering pressure of 10 MPa, and a calendering time of 5 min. After calendering, the obtained magnetic sheet was taken out, magnetized, and its surface magnetism was tested.

[0027] The beneficial effects of this invention are:

[0028] 1. Reduced energy consumption: This invention can obtain magnetic powder with an average particle size of 20μm by using only low-temperature negative pressure hydrogen pulverization method without dehydrogenation treatment. Compared with the HDDR method and high-pressure method, the equipment investment of this invention is small and the energy consumption is greatly reduced, which is conducive to saving energy and reducing production costs.

[0029] 2. Improved production efficiency: The nitriding process of this invention adopts a continuous slow heating method, which is different from the traditional segmented heat preservation method. This improves the activity of nitrogen atoms, making the nitriding process easier and the nitrogen content higher, thereby improving production efficiency.

[0030] 3. Improved magnetic powder performance: The magnetic sheets prepared by the anisotropic samarium iron nitrogen magnetic powder provided by the preparation method of the present invention have high magnetic properties, which is beneficial to improving the performance of the prepared magnetic components.

[0031] In summary, the present invention provides a method for preparing samarium iron nitrogen magnetic powder, which, compared with the prior art, has the advantages of simple preparation process, low energy consumption, high production efficiency, small magnetic powder particle size, high magnetic properties and good magnetic crystal anisotropy, and is an ideal method for preparing samarium iron nitrogen magnetic powder. Attached Figure Description

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] Figure 1 This is a temperature-time variation graph in a method for preparing anisotropic samarium iron nitrogen magnetic powder according to Embodiment 1 of the present invention.

[0034] Figure 2 This is a graph showing the pressure change over time in a method for preparing anisotropic samarium iron nitrogen magnetic powder according to Embodiment 1 of the present invention. Detailed Implementation

[0035] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0038] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0039] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0040] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0041] This application provides a method for preparing anisotropic samarium iron nitrogen magnetic powder, comprising the following steps:

[0042] Step 1: Prepare Sm and Fe, melt them to obtain samarium iron alloy steel liquid;

[0043] Step 2: Pour the molten samarium-iron alloy steel onto the cooling roller to obtain samarium-iron alloy sheets;

[0044] Step 3: Place the iron-samarium alloy sheet in a vacuum heat treatment furnace for homogenization treatment. After homogenization treatment, cool the alloy sheet to 200-300°C. In a vacuum environment, introduce hydrogen into the furnace. The absolute pressure of the hydrogen is controlled at 0.05-0.1 MPa. Hydrogenation treatment is carried out for 2 hours.

[0045] Step 4: After hydrogenation, the temperature is raised to 400°C, nitrogen gas is introduced to 0.5 MPa, the temperature is raised to 530°C, and then the furnace temperature is lowered to room temperature to obtain the anisotropic samarium iron nitrogen magnetic powder.

[0046] In some embodiments, step 1 is performed as follows:

[0047] Prepare Sm and Fe. Add 50% of the total mass of Sm and all of the Fe to the melting furnace. Evacuate the inside of the melting furnace and heat it until Sm and Fe melt to a liquid state. Then add the remaining Sm. After it is completely melted, continue melting for 40 minutes to obtain samarium-iron alloy steel liquid.

[0048] In some embodiments, the heating rate during step 4, when heating to 400°C, is 10°C / min.

[0049] In some embodiments, the atomic percentages of Sm and Fe in step 1 are Sm 2.2 Fe 17 Then, the atomic percentages were converted to mass percentages; among which, the theoretical alloy composition Sm2Fe 17 In comparison, Sm was 10% excessive.

[0050] In some embodiments, Sm in step 1 is samarium particles with a particle size of 1 to 100 mm and a purity of ≥99.9%.

[0051] In some embodiments, Fe in step 1 is an iron rod with a purity ≥ 99%.

[0052] In some embodiments, the internal pressure of the smelting furnace in step 1 is ≤10Pa.

[0053] In some embodiments, the cooling roller rotation speed in step 2 is 2 r / min.

[0054] In some embodiments, the homogenization pressure in step 3 is 1×10⁻⁶. -2 Pa, temperature 1000℃, time 8h.

[0055] In some embodiments, the average particle size of the anisotropic samarium iron nitrogen magnetic powder in step 4 is 20 μm.

[0056] In some embodiments, the method for preparing anisotropic samarium iron nitrogen magnetic powder further includes a testing step for the anisotropic samarium iron nitrogen magnetic powder, the testing step being as follows:

[0057] The anisotropic samarium iron nitrogen magnetic powder and polyvinyl chloride (CPE) were mixed at a mass ratio of 10:90. The mixture was then placed in a calender and calendered at a calendering temperature of 180°C, a calendering pressure of 10 MPa, and a calendering time of 5 min. After calendering, the obtained magnetic sheet was taken out, magnetized, and its surface magnetism was tested.

[0058] The following description, in conjunction with specific embodiments, provides further details.

[0059] Example 1

[0060] Please see Figures 1-2 A method for preparing anisotropic samarium iron nitrogen magnetic powder includes the following steps:

[0061] Step 1, press Sm 2.2 Fe 17 The raw materials were prepared according to atomic percentages. Fe was selected from iron rods with a purity of 99%, and Sm was selected from samarium particles with a purity of 99.9%. The samarium particles had a particle size of 1–10 mm, consistent with the theoretical alloy composition Sm₂Fe. 17 In comparison, Sm was 10% excess, iron rods weighed 75.95 kg, and samarium particles weighed 26.45 kg;

[0062] Step 2: Add 50% of the total mass of Sm and all of Fe from the weighed raw materials to the melting furnace. Put the remaining Sm into the secondary feeding hopper. Pull the furnace to 10 Pa and heat until Sm and Fe melt to liquid state. Then add the remaining Sm and continue melting for 40 minutes until completely melted. Measure the temperature of the samarium iron alloy steel melt and record it in Table 1.

[0063] Step 3: The molten samarium iron alloy steel is poured through an tundish and runner onto cooling rollers. The cooling rollers rotate at 2 r / min, allowing the molten samarium iron alloy steel to form Sm2Fe during the cooling process. 17 The phase falls onto the water-cooling plate below and is cooled to room temperature to obtain a samarium iron alloy sheet;

[0064] Step 4: Place the samarium iron alloy sheet into a vacuum heat treatment furnace and evacuate it to a vacuum level of 1×10⁻⁶. -2 Pa, heat to 1000℃, hold for 8 hours, then stop heating;

[0065] Step 5: Cool to 260℃ and keep warm. In a vacuum environment, introduce hydrogen into the vacuum heat treatment furnace. The absolute pressure of hydrogen is controlled at 0.08MPa and the hydrogenation time is 2h.

[0066] Step 6: After hydrogenation, the temperature is increased to 400°C at a rate of 10°C / min, and nitrogen gas is introduced to 0.5 MPa. Then, the temperature is increased to 530°C at a rate of 0.2°C / min. The furnace temperature is then reduced to room temperature to obtain anisotropic samarium iron nitrogen magnetic powder with an average particle size of 20 μm.

[0067] Step 7: Mix anisotropic samarium iron nitrogen magnetic powder and polyvinyl chloride (CPE) at a mass ratio of 10:90. Then, put the mixture into a calender and calender it at a calendering temperature of 180℃, a calendering pressure of 10MPa, and a calendering time of 5min. After calendering, take out a magnetic sheet with a thickness of 0.4mm, magnetize the magnetic sheet, test the surface magnetism of the magnetic sheet, and record the test results in Table 1.

[0068] Example 2

[0069] A method for preparing anisotropic samarium iron nitrogen magnetic powder, which differs from Example 1 only in that the step 5 in Example 1, "cooling to 260°C and holding at that temperature", is changed to "cooling to 200°C and holding at that temperature".

[0070] Example 3

[0071] A method for preparing anisotropic samarium iron nitrogen magnetic powder, which differs from Example 1 only in that the step 5 in Example 1, "cooling to 260°C and holding at that temperature", is changed to "cooling to 300°C and holding at that temperature".

[0072] Example 4

[0073] A method for preparing anisotropic samarium iron nitrogen magnetic powder, which differs from Example 1 only in that the absolute hydrogen pressure in step 5 of Example 1 is adjusted to "the absolute hydrogen pressure is controlled at 0.05 MPa".

[0074] Example 5

[0075] A method for preparing anisotropic samarium iron nitrogen magnetic powder, which differs from Example 1 only in that the absolute hydrogen pressure in step 5 of Example 1 is adjusted to "the absolute hydrogen pressure is controlled at 0.1 MPa".

[0076] Example 6

[0077] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that the phrase "then heat up to 530°C at a heating rate of 0.2°C / min" in step 6 of Example 1 is adjusted to "then heat up to 530°C at a heating rate of 0.1°C / min".

[0078] Example 7

[0079] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that the phrase "then heat up to 530°C at a heating rate of 0.2°C / min" in step 6 of Example 1 is adjusted to "then heat up to 530°C at a heating rate of 0.5°C / min".

[0080] Example 8

[0081] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that step 6 in Example 1, "taking out the magnetic sheet with a thickness of 0.4 mm", is changed to "taking out the magnetic sheet with a thickness of 0.3 mm".

[0082] Example 9

[0083] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that step 6 in Example 1, "taking out the magnetic sheet with a thickness of 0.4 mm", is changed to "taking out the magnetic sheet with a thickness of 0.5 mm".

[0084] Comparative Example 1

[0085] A method for preparing anisotropic samarium iron nitrogen magnetic powder, which differs from Example 1 only in that the step 5 in Example 1, "cooling to 260°C and holding at that temperature", is changed to "cooling to 150°C and holding at that temperature".

[0086] Comparative Example 2

[0087] A method for preparing anisotropic samarium iron nitrogen magnetic powder, which differs from Example 1 only in that the absolute hydrogen pressure in step 5 of Example 1 is adjusted to "the absolute hydrogen pressure is controlled at 0.01 MPa".

[0088] Comparative Example 3

[0089] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that the phrase "then heat up to 530°C at a heating rate of 0.5°C / min" in step 6 of Example 1 is adjusted to "then heat up to 530°C at a heating rate of 5°C / min".

[0090] Comparative Example 4

[0091] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that step 6 in Example 1 is adjusted. The operation of step 6 in this comparative example is as follows:

[0092] After hydrogenation, the temperature was increased to 400℃ at a rate of 10℃ / min, nitrogen gas was introduced to 0.5MPa, and the temperature was held for 0.5h. Then, the temperature was increased to 450℃ for 10min and held for 3h. Then, the temperature was increased to 530℃ for 10min and held for 5h. The heating was then stopped, and the furnace temperature was reduced to room temperature to obtain anisotropic samarium iron nitrogen magnetic powder.

[0093] Comparative Example 5

[0094] A method for preparing anisotropic samarium iron nitrogen magnetic powder, compared with Example 1, differs only in that a dehydrogenation step is added, that is, step 6 of Example 1 is adjusted. The operation of step 6 in this comparative example is as follows:

[0095] The temperature was increased to 400℃ at a rate of 10℃ / min, held for 30 min, and then dehydrogenation was performed. After dehydrogenation, the vacuum was reduced to below 1 Pa, and nitrogen was introduced to 0.5 MPa. Then the temperature was increased to 530℃ at a rate of 0.2℃ / min. The furnace temperature was then reduced to room temperature to obtain anisotropic samarium iron nitrogen magnetic powder with an average particle size of 20 μm.

[0096] The magnetic sheets obtained in Examples 1-9 and Comparative Examples 1-5 were tested. The thickness of the magnetic sheets was measured with vernier calipers and the surface magnetic field was measured with an FE-103 gaussmeter. The results are recorded in Table 1.

[0097] Table 1

[0098]

[0099] Analysis of the data in Table 1 shows that the magnetic sheets prepared from the samarium iron nitrogen magnetic powder obtained in Examples 1-9 have a thickness of 0.3-0.5 mm and a surface magnetic field of 960-1230 Gs, exhibiting good magnetic properties.

[0100] Specifically, the test results from Examples 1, 2, 3 and Comparative Example 1 show that the higher the hydrogen rupture temperature, the finer the magnetic powder is broken into during the hydrogen rupture process. In the subsequent nitriding process, the nitriding effect is better, the nitrogen content of the magnetic powder is higher, and thus it has higher magnetic properties. After being made into a magnetic sheet, it has higher surface magnetism.

[0101] The test results from Examples 1, 4, 5 and Comparative Example 2 show that the higher the hydrogen breaking pressure, the more hydrogen the alloy sheet absorbs during the hydrogen breaking process, and the more nitrogen it absorbs in the subsequent nitriding process. This results in a higher nitrogen content in the magnetic powder, thus giving it higher magnetic properties. After being made into a magnetic sheet, it has a higher surface magnetism.

[0102] The test results from Examples 1, 6, 7 and Comparative Example 3 show that during the nitriding process, the slower the heating rate, the better the nitriding effect, the higher the magnetic powder performance, and thus the higher the surface magnetism.

[0103] As can be seen from the test results of Example 1 and Comparative Example 4, slow heating has better magnetic properties than step heating because the activity of nitrogen gas also increases slowly during the slow heating process, resulting in a better nitriding effect.

[0104] As can be seen from the test results in Example 1 and Comparative Example 5, no dehydrogenation treatment is better than dehydrogenation treatment. Without dehydrogenation, hydrogen atoms open channels for nitrogen atoms to permeate, making nitriding easier. After dehydrogenation, there are no such channels, making the nitriding process more difficult, resulting in poor nitriding effect and reduced performance.

[0105] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0106] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing anisotropic samarium iron nitrogen magnetic powder, characterized in that, Includes the following steps: Step 1: Prepare Sm and Fe, melt them to obtain samarium iron alloy steel liquid; Step 2: Pour the molten samarium-iron alloy steel onto the cooling roller to obtain samarium-iron alloy sheets; Step 3: Place the iron-samarium alloy sheet in a vacuum heat treatment furnace for homogenization treatment. After homogenization treatment, cool the alloy sheet to 200-260°C or 300°C. In a vacuum environment, introduce hydrogen into the furnace. The absolute pressure of the hydrogen is controlled at 0.08-0.1 MPa. Hydrogenation treatment is carried out for 2 hours. Step 4: After hydrogenation, the temperature is increased to 400°C at a rate of 10°C / min, and nitrogen gas is introduced to 0.5MPa. Then, the temperature is increased to 530°C at a rate of 0.1°C / min. The furnace temperature is then reduced to room temperature. No dehydrogenation treatment is required to obtain anisotropic samarium iron nitrogen magnetic powder with an average particle size of 20μm. The homogenization pressure in step 3 is 1×10⁻⁶. -2 Pa, temperature 1000℃, time 8h.

2. The method for preparing anisotropic samarium iron nitrogen magnetic powder according to claim 1, characterized in that, Step 1 involves the following steps: Prepare Sm and Fe. Add 50% of the total mass of Sm and all of the Fe to the melting furnace. Evacuate the inside of the melting furnace and heat it until Sm and Fe melt to a liquid state. Then add the remaining Sm. After it is completely melted, continue melting for 40 minutes to obtain samarium-iron alloy steel liquid.

3. The method for preparing anisotropic samarium iron nitrogen magnetic powder according to claim 2, characterized in that, In step 1, the atomic percentage of Sm and Fe is Sm 2.2 Fe 17 .

4. The method for preparing anisotropic samarium iron nitrogen magnetic powder according to claim 2, characterized in that, The internal pressure of the smelting furnace is ≤10Pa.

5. The method for preparing anisotropic samarium iron nitrogen magnetic powder according to claim 1, characterized in that, It also includes testing procedures for anisotropic samarium iron nitrogen magnetic powder, the testing procedures being as follows: Anisotropic samarium iron nitrogen magnetic powder and polyvinyl chloride are mixed, and then the mixture is placed in a calender for calendering. After calendering is completed, the obtained magnetic sheet is taken out, magnetized, and then the surface magnetism of the magnetic sheet is tested.

6. The method for preparing anisotropic samarium iron nitrogen magnetic powder according to claim 5, characterized in that, The mass ratio of anisotropic samarium iron nitrogen magnetic powder to polyvinyl chloride is 10:

90.

7. The method for preparing anisotropic samarium iron nitrogen magnetic powder according to claim 5, characterized in that, The calendering temperature is 180℃, the calendering pressure is 10MPa, and the calendering time is 5min.

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