A high-performance samarium-cobalt magnet and its preparation method

Abstract

This invention relates to a high-performance samarium-cobalt magnet and its preparation method, belonging to the field of magnet technology. This invention discloses a high-performance samarium-cobalt magnet, wherein the samarium-cobalt magnet is composed of a surface coated with N... y H z Sm layer (1‑x) M x (Co a Fe b Cu c Zr d ) e The magnet is made of magnetic powder material, wherein 0 ≤ x < 1, 0 ≤ a ≤ 1, 0 < b < 1, 0 < c < 1, 0 < d < 1, and 4.5 ≤ e ≤ 9. This invention also discloses a method for preparing a high-magnetic-performance samarium-cobalt magnet, the method comprising: mixing raw materials according to elemental ratios, and performing alloy melting using vacuum induction melting technology to obtain Sm... (1‑x) M x (Co a Fe b Cu c Zr d ) e Casting ingots; obtaining magnetic powder from the ingots through coarse crushing; then uniformly coating the surface of the magnetic powder with N. y H z Then, the mixed powder is post-processed to obtain a samarium cobalt magnet with high magnetic properties.

Description

Technical Field

[0001] This invention belongs to the field of magnet technology and relates to a high-magnetic-performance samarium-cobalt magnet and its preparation method. Background Technology

[0002] In recent years, grain boundary diffusion technology has made significant progress in the field of NdFeB magnets. With the maturity of the grain boundary diffusion process, most NdFeB manufacturers have developed grain boundary diffusion technologies suitable for their own development, and have conducted extensive research and exploration in areas such as diffusion sources, coating processes, heat treatment processes, and magnet formulations. The performance of NdFeB magnets has thus been greatly improved. Samarium cobalt (SCo) possesses excellent high-temperature performance and corrosion resistance, making it irreplaceable by NdFeB magnets in harsh environments and where high reliability is required. In recent years, SCo has also made some progress in improving magnetic properties. Currently, the highest energy product that companies can mass-produce is 32-33 MGOe, with the highest reported energy product in the literature being 35 MGOe. However, this is still lower than that of NdFeB magnets. High-temperature SCo and low-temperature coefficient SCo also face the problem of low energy products, generally between 10-20 MGOe. To improve the performance of samarium-cobalt magnets, researchers have developed a liquid-phase process. This process can help regulate the microstructure and composition of the magnet, thereby improving the overall magnetic properties of low-remanence temperature coefficient magnets. The low-temperature coefficient samarium-cobalt magnets prepared by this method have achieved good results, with a maximum magnetic energy product of 21.82 MGOe and a maximum HcJ of 22 kOe. The magnet's α (20-100℃) increased from -0.0213% / ℃ to -0.0079% / ℃, and β (20-200℃) increased from -0.2632% / ℃ to -0.1132% / ℃. However, simply combining the liquid-phase process with existing processes cannot meet practical requirements; therefore, further research on related technologies based on this theory is needed.

[0003] The cellular structure is the core structure of samarium-cobalt magnets. Samarium-cobalt magnets prepared using traditional processes exhibit uneven and large cellular structures with thin and uneven cell walls, containing discontinuous regions. This incomplete cellular structure significantly impacts magnet performance. Magnets prepared using diffusion processes have smaller, more uniform cellular structures with continuous and uniform cell walls, resulting in a homogeneous and complete cellular structure. Excessive element addition further reduces the size and uniformity of the cellular structure, increases cell wall thickness, and may even lead to aggregation, thus disrupting the uniformity of the cellular structure. Therefore, diffusion processes can optimize the magnet's microstructure by distributing elements uniformly along the cell wall phase, thereby reducing the amount of diffusion element required. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a surface-coated N... y Hz Sm (1-x) M x (Co a Fe b Cu c Zr d ) e Samarium cobalt magnets with high magnetic properties are made from magnetic powder materials.

[0005] The objective of this invention can be achieved through the following technical solution: a samarium-cobalt magnet with high magnetic performance, wherein the samarium-cobalt magnet is coated with N2 on its surface. y H z Sm layer (1-x) M x (Co a Fe b Cu c Zr d ) e Made of magnetic powder material, wherein 0≤x<1, 0≤a≤1, 0<b<1, 0<c<1, 0<d<1, 4.5≤e≤9.

[0006] Preferably, the values ​​are 0.5≤a≤0.7, 0.2≤b≤0.4, 0.01≤c≤0.08, and 0.01≤d≤0.05.

[0007] Further preferred, a+b+c+d=1.

[0008] Preferably, the N y H z The mass ratio of the magnet powder to the magnet powder is (0.001-0.1):1.

[0009] Further preferred, the N y H z It diffuses into the interior of the magnet powder and is distributed in a concentration gradient.

[0010] This invention involves heat treatment in an environment containing an inert gas or a vacuum, resulting in N y H z It diffuses into the interior of the alloy and is distributed in a concentration gradient.

[0011] Preferably, M includes one or more of Tb, Dy, La, Ce, Nd, Pr, Gd, Er, Y, Ho, Ga, Tm, and Lu.

[0012] Preferably, the N y H zIn the layer, N is one or more of Tb, Dy, La, Ce, Nd, Pr, Gd, Y, Ho, Ga, Co, Cu, Al, Zn, Nb, Zr, Ti, Tm, Lu, Fe, and Sm, and H is one of O, F, and H elements, where 0 < y ≤ 10 and 0 ≤ z < 10.

[0013] N is used in this invention y H z By coating the magnetic powder, the method makes it easier to achieve diffusion of the diffusion source due to the small particle size of the powder, resulting in more uniform diffusion.

[0014] More preferably, N is one or more of DyNd, DyCu, Nd, Dy, Cu, Gd, and Er.

[0015] Furthermore, the N y H z It is one or more of DyNdH2, Cu, Dy, DyH3, Gd, and Er.

[0016] When N contains two or more elements, the metal is first smelted according to the proportions, and then alloy powder is obtained by mechanical crushing or hydrogen crushing. When N is a single element, mechanical crushing and hydrogen crushing can be performed directly without smelting to obtain powder.

[0017] A method for preparing a high-magnetic-performance samarium-cobalt magnet, the method comprising: weighing raw materials according to elemental ratios, performing alloy melting using vacuum induction melting technology, and obtaining Sm (1-x) M x (Co a Fe b Cu c Zr d ) e Casting ingots; obtaining magnetic powder from the ingots through coarse crushing; then uniformly coating the surface of the magnetic powder with N. y H z Then, the mixed powder is post-processed to obtain a samarium cobalt magnet with high magnetic properties.

[0018] Preferably, the samarium cobalt magnet includes one or more of sintered samarium cobalt magnets and bonded samarium cobalt magnets.

[0019] Preferably, the N is uniformly coated on the surface of the magnet powder. y H z The methods include one or more of spin vapor deposition and spraying.

[0020] Preferably, the post-processing includes one or more of grinding, curing, orientation molding, heat treatment, and bonding.

[0021] More preferably, the heat treatment includes one or more of sintering, solution treatment, primary aging, and secondary aging treatment.

[0022] Preferably, the average particle size of the powder obtained after coarse crushing is 500-5000 μm; the average particle size of the powder obtained after grinding is 2-6 μm.

[0023] Further preferably, the average particle size of the powder obtained after coarse crushing is 2000-5000 μm.

[0024] Further preferably, the average particle size of the powder obtained after grinding is 3-5 μm.

[0025] More preferably, the grinding process employs one or more of air jet milling and ball milling.

[0026] Preferably, the curing process is carried out at a temperature of 600-900℃ for 1-5 hours.

[0027] The curing process can increase the bonding force between the coating powder and the magnet powder, making the coating powder less likely to fall off, ensuring diffusion and thus guaranteeing the performance of the magnet.

[0028] Preferably, the sintering process is carried out at a temperature of 1210-1240℃ for 1-3 hours.

[0029] Preferably, the solution treatment process is carried out at a temperature of 1180-1200℃ for 2-4 hours.

[0030] Preferably, the first-stage aging process is carried out at a temperature of 830-850℃ for a time of 45-60 hours.

[0031] Preferably, the secondary aging process is carried out at a temperature of 370-420℃ for 4-6 hours.

[0032] Further preferably, the cooling rate during the transition from the first-stage aging to the second-stage aging is 0.1-10℃ / min.

[0033] Preferably, the post-treatment of the sintered samarium cobalt magnet includes grinding, curing, sintering, solution treatment, first-stage aging, and second-stage aging.

[0034] Preferably, the post-processing steps of the bonded samarium cobalt magnet include sintering, solution treatment, primary aging, secondary aging, and bonding.

[0035] Preferably, the preparation process of the bonded samarium cobalt magnet includes: uniformly mixing the heat-treated magnet powder and the adhesive, rolling it into a magnet with a thickness of 5-20 mm, and then curing it at 100-140℃.

[0036] Further optimization involves using coarsely crushed powder as the magnet powder in the bonded samarium cobalt magnet.

[0037] Further preferably, the adhesive includes one or more of polyethylene resin, nylon polyamide, polyester, and nitrile rubber.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The package obtained by this invention contains N y H z Sm (1-x) M x (Co a Fe b Cu c Zr d ) e Samarium cobalt magnets made from magnet powder have high magnetic properties.

[0040] 2. The present invention Sm (1-x) M x (Co a Fe b Cu c Zr d ) e In the magnetic powder, 0 ≤ x < 1.

[0041] 3. The method of the present invention enables samarium cobalt magnets to obtain higher magnetic energy and coercivity.

[0042] 4. In this invention, the magnetic powder is cured before orientation molding, which can increase the bonding force between the coating powder and the magnet powder, making the coating powder less likely to fall off, ensuring diffusion and thus ensuring the performance of the magnet.

[0043] 5. The preparation process of this invention is carried out in an inert atmosphere or vacuum environment to avoid Sm being oxidized and thus reducing performance. Attached Figure Description

[0044] Figure 1 This is a scanning electron microscope image of the surface layer of samarium cobalt magnetic powder prepared in Example 1 of the present invention.

[0045] Figure 2 This is a scanning electron microscope image of the samarium cobalt magnetic powder prepared in Example 1 of the present invention at a distance of one-quarter from the surface.

[0046] Figure 3 This is a scanning electron microscope image of the center of the samarium cobalt magnetic powder prepared in Example 1 of the present invention. Detailed Implementation

[0047] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0048] Example 1

[0049] The raw materials were proportioned according to element ratios, and the alloy was smelted using vacuum induction melting technology to obtain Sm. 0.8 Dy 0.1 Nd 0.1 (Co 0.66 Fe 0.25 Cu 0.06 Zr 0.03 ) 7.2 The ingots were coarsely crushed to obtain magnetic powder with an average particle size of 2000 μm. DyNdH2 and magnetic powder were then sprayed together at a mass ratio of 0.008:1 to uniformly coat the surface of the magnetic powder with DyNdH2. The mixed powder was then milled by air jet milling to reduce the average particle size of the magnetic powder to 3.5 μm. The powder was then cured at 650℃ for 1 hour. The cured powder was then ball-milled to a particle size of 4 μm. Orientation molding was performed under argon protection, followed by pressing at 200 MPa for 3 minutes to obtain a blank. The blank was placed in a vacuum sintering furnace, heated to 1220℃ for 2 hours, then cooled to 1190℃ for solution treatment and held for 3 hours. After furnace cooling, a sintered samarium-cobalt magnet blank was obtained. The sintered samarium-cobalt magnet blank was then subjected to a first aging treatment under argon atmosphere at 840℃ for 50 hours with a cooling rate of 0.8℃ / min. A second aging treatment was then performed at 400℃ for 5 hours to obtain the sintered samarium-cobalt magnet. A scanning electron microscope image of the magnet powder before air jet milling is shown below. Figure 1-3 As shown, the percentage of Dy atoms at position 178 is 7.91%, at position 196 it is 0.55%, and at position 1102 it is 0.2%. The concentration of Dy elements gradually decreases from the surface to the interior of the magnetic powder, showing a concentration gradient distribution. The performance of the prepared samarium-cobalt magnet is shown in Table 1.

[0050] Example 2

[0051] The raw materials were proportioned according to element ratios, and the alloy was smelted using vacuum induction melting technology to obtain Sm. 0.8 Dy 0.1 Nd 0.1 (Co 0.66 Fe 0.25 Cu 0.06 Zr 0.03 ) 7.2The ingot was coarsely crushed to obtain magnetic powder with an average particle size of 2100 μm. DyNdH2 was then mixed with the magnetic powder at a mass ratio of 0.008:1 and sprayed to uniformly coat the magnetic powder surface with DyNdH2. The mixed powder was then milled using an air jet mill to achieve an average particle size of 3.5 μm. Orientation shaping was performed under argon protection, followed by pressing at 200 MPa for 3 minutes to obtain… The blank was placed in a vacuum sintering furnace and sintered at 1220℃ for 2 hours, then cooled to 1190℃ for solution treatment and held for 3 hours. After furnace cooling, a sintered samarium-cobalt magnet blank was obtained. The sintered samarium-cobalt magnet blank was then subjected to a first aging treatment in an argon atmosphere at 840℃ for 52 hours, with a cooling rate of 1℃ / min. The blank was then cooled to 400℃ for a second aging treatment and held for 5 hours to obtain the sintered samarium-cobalt magnet. The properties of the samarium-cobalt magnet are shown in Table 1.

[0052] Example 3

[0053] The raw materials were proportioned according to element ratios, and the alloy was smelted using vacuum induction melting technology to obtain Sm. 0.8 Dy 0.2 (Co 0.66 Fe 0.25 Cu 0.06 Zr 0.03 ) 7.2 The ingot was coarsely crushed to obtain magnetic powder with an average particle size of 2600 μm. DyNdH2 was then mixed with the magnetic powder at a mass ratio of 0.008:1 and sprayed to uniformly coat the magnetic powder surface with DyNdH2. The mixed powder was then milled using an air jet mill to achieve an average particle size of 4 μm. Following this, the powder was oriented and shaped under argon protection, and then pressed at 200 MPa for 3 minutes to obtain… The blank was placed in a vacuum sintering furnace and sintered at 1220℃ for 2 hours, then cooled to 1190℃ for solution treatment and held for 3 hours. After furnace cooling, a sintered samarium-cobalt magnet blank was obtained. The sintered samarium-cobalt magnet blank was then subjected to a first aging treatment in an argon atmosphere at 830℃ for 50 hours, with a cooling rate controlled at 1.2℃ / min. The blank was then cooled to 390℃ for a second aging treatment and held for 5 hours to obtain the sintered samarium-cobalt magnet. The properties of the samarium-cobalt magnet are shown in Table 1.

[0054] Example 4

[0055] The raw materials were proportioned according to their elemental ratios, and Sm(Co) was obtained by alloy smelting using vacuum induction melting technology. 0.66 Fe 0.3 Cu 0.01 Zr 0.03 ) 7.2The ingot was coarsely crushed to obtain magnetic powder with an average particle size of 2700 μm. DyNdH2 was then mixed with the magnetic powder at a mass ratio of 0.008:1 and sprayed to uniformly coat the magnetic powder surface with DyNdH2. The mixed powder was then milled using an air jet mill to achieve an average particle size of 4.1 μm. Following this, the powder was oriented and shaped under argon protection, and then pressed at 200 MPa for 3 minutes to obtain… A blank was obtained; the blank was placed in a vacuum sintering furnace and sintered at 1220℃ for 2.5 h, then cooled to 1195℃ for solution treatment and held for 3 h. After furnace cooling, a sintered samarium-cobalt magnet blank was obtained; the sintered samarium-cobalt magnet blank was then subjected to a first aging treatment in an argon atmosphere at 830℃ for 50 h with a cooling rate of 1℃ / min, followed by a second aging treatment at 400℃ for 5 h, to obtain the sintered samarium-cobalt magnet. The properties of the samarium-cobalt magnet are shown in Table 1.

[0056] Example 5

[0057] The raw materials were proportioned according to their elemental ratios, and Sm(Co) was obtained by alloy smelting using vacuum induction melting technology. 0.66 Fe 0.3 Cu 0.01 Zr 0.03 ) 7.2 The alloy ingot was coarsely crushed to obtain magnetic powder with an average particle size of 2200 μm. A layer of Cu powder was then coated onto the surface of the powder using a spraying method, with a Cu powder to magnetic powder mass ratio of 0.004:1. The resulting mixed powder was placed in a vacuum sintering furnace, heated to 1210℃ for 2 hours, then cooled to 1170℃ for solution treatment and held for 3 hours. After furnace cooling, it was transferred to an argon atmosphere for a first aging treatment at 830℃ for 50 hours, with a cooling rate controlled at 0.8℃ / min. A second aging treatment was then performed at 410℃ for 5 hours, yielding high-performance powder. This powder was further crushed to obtain powder with a particle size of 2200 μm. Then, 10% ethylene resin and nitrile rubber were added and uniformly mixed, rolled into a 10 mm thick magnet, and then cured at 120℃ to prepare a bonded samarium-cobalt magnet. The properties of the samarium-cobalt magnet are shown in Table 1.

[0058] Example 6

[0059] The raw materials were proportioned according to their elemental ratios, and Sm(Co) was obtained by alloy smelting using vacuum induction melting technology. 0.66 Fe 0.3 Cu 0.01 Zr 0.03 ) 7.2The ingot is coarsely crushed to obtain magnetic powder with an average particle size of 1800 μm. Magnetic powder and Cu powder are weighed in a mass ratio of 0.004:1 and uniformly coated with Cu on the surface of the magnetic powder by vapor deposition. The mixed powder is then cured at 650℃ for 1.5 h, and the cured powder is then crushed to 3 μm using a ball milling process. Orientation molding was performed under argon protection, followed by pressing at 200 MPa for 3 minutes to obtain a blank. The blank was placed in a vacuum sintering furnace, heated to 1210℃ and sintered for 2 hours, then cooled to 1180℃ and held for 3 hours. After furnace cooling, a sintered samarium-cobalt magnet blank was obtained. The sintered samarium-cobalt magnet blank was then subjected to a first aging treatment under argon atmosphere at 830℃ for 50 hours with a controlled cooling rate of 0.9℃ / min. A second aging treatment was then performed at 400℃ for 5 hours to obtain the sintered samarium-cobalt magnet. The properties of the samarium-cobalt magnet are shown in Table 1.

[0060] Comparative Example 1

[0061] The raw materials were proportioned according to element ratios, and the alloy was smelted using vacuum induction melting technology to obtain Sm. 0.8 Dy 0.1 Nd 0.1 (Co 0.66 Fe 0.25 Cu 0.06 Zr 0.03 ) 7.2 The ingots were coarsely crushed and ground into magnetic powder with an average particle size of 4 μm through an air jet mill. The powder was then oriented and shaped under argon protection, and pressed at 200 MPa for 3.5 min to obtain a billet. The billet was placed in a vacuum sintering furnace, heated to 1220℃ for 2 h, then cooled to 1190℃ for solution treatment and held for 3 h. After furnace cooling, a sintered samarium-cobalt magnet billet was obtained. The sintered samarium-cobalt magnet billet was then subjected to a first aging treatment under argon atmosphere at 840℃ for 50 h with a controlled cooling rate of 0.8℃ / min. A second aging treatment was then performed at 400℃ for 5 h, yielding the sintered samarium-cobalt magnet. The properties of the samarium-cobalt magnet are shown in Table 1.

[0062] Table 1. Magnet Performance Table

[0063]

[0064] According to the data in the table, the surface is coated with N using the method of the present invention. y H z Sm layer (1-x) M x (Co a Fe b Cu c Zrd ) e Samarium cobalt magnets made from magnet powder materials are superior to those without N. y H z The layered magnets have better coercivity and remanence temperature coefficient; the samarium cobalt magnets made of Cu-coated magnetic powder have better coercivity and magnetic energy product, and the samarium cobalt magnets made of DyNdH2-coated magnetic powder have better thermal stability; bonded samarium cobalt magnets can be used to prepare magnets with complex shapes; the thermal stability of samarium cobalt magnets made when M is two elements is better than that of samarium cobalt magnets made when M is one element, and even better than that of samarium cobalt magnets made without M.

[0065] In summary, through the method of the present invention, the surface is coated with N y H z Sm layer (1-x) M x (Co a Fe b Cu c Zr d ) e Samarium cobalt magnets made from magnetic powder materials have good coercivity and magnetic energy.

[0066] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for preparing a samarium-cobalt magnet, characterized in that, include: The raw materials were proportioned according to element ratios, and the alloy was smelted using vacuum induction melting technology to obtain Sm. (1-x) M x (Co a Fe b Cu c Zr d ) e Ingot; wherein 0≤x<1, 0≤a≤1, 0<b<1, 0<c<1, 0<d<1, 4.5≤e≤9; M includes one or more of Tb, Dy, La, Ce, Nd, Pr, Gd, Er, Y, Ho, Ga, Tm, and Lu; The ingot is coarsely crushed to obtain magnetic powder; then, nitrogen is uniformly coated onto the surface of the magnetic powder. y H z The coating method includes one or more of spin vapor deposition and spraying to obtain a surface coating N. y H z Sm layer (1-x) M x (Co a Fe b Cu c Zr d ) e Magnet powder material; the N y H z It is DyNdH2; Then coat the surface with N y H z Sm layer (1-x) M x (Co a Fe b Cu c Zr d ) e The magnetic powder material is post-processed to obtain samarium cobalt magnets; Where, N y H z It diffuses into the interior of the magnetic powder and is distributed in a concentration gradient; The samarium cobalt magnet includes one or more of sintered samarium cobalt magnets and bonded samarium cobalt magnets; The post-processing steps for the sintered samarium cobalt magnet include grinding, curing, sintering, solution treatment, first-stage aging, and second-stage aging. The post-processing steps for the bonded samarium cobalt magnets include sintering, solution treatment, primary aging, secondary aging, and bonding.

2. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, The N y H z Layers and Sm (1-x) M x (Co a Fe b Cu c Zr d ) e The mass ratio of the magnet powder is (0.001-0.1):

1.

3. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, The Sm (1-x) M x (Co a Fe b Cu c Zr d ) e is Sm 0.8 Dy 0.1 Nd 0.1 (Co 0.66 Fe 0.25 Cu 0.06 Zr 0.03 ) 7.2 .

4. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, The average particle size of the powder obtained after coarse crushing is 500-5000 μm; the average particle size of the powder obtained after grinding is 2-6 μm.

5. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, When the samarium-cobalt magnet is a sintered samarium-cobalt magnet, the curing treatment temperature is 600-900℃ and the time is 1-5h.

6. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, The solution treatment process is carried out at a temperature of 1180-1200℃ for 2-4 hours.

7. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, The first-stage aging process is carried out at a temperature of 830-850℃ for 45-60 hours; the second-stage aging process is carried out at a temperature of 370-420℃ for 4-6 hours.

8. The method for preparing a samarium-cobalt magnet according to claim 1, characterized in that, The preparation method includes: The raw materials were proportioned according to element ratios, and the alloy was smelted using vacuum induction melting technology to obtain Sm. 0.8 Dy 0.1 Nd 0.1 (Co 0.66 Fe 0.25 Cu 0.06 Zr 0.03 ) 7.2 The ingots were coarsely crushed to obtain magnetic powder with an average particle size of 2000 μm. DyNdH2 was then sprayed onto the magnetic powder at a mass ratio of 0.008:1 to uniformly coat the magnetic powder surface with DyNdH2. The mixed powder was then milled using an air jet mill to achieve an average particle size of 3.5 μm. The powder was then cured at 650℃ for 1 hour. The cured powder was then ball-milled to a particle size of 4 μm. Orientation shaping was performed under argon protection, followed by pressing at 200 MPa for 3 minutes. A blank was obtained; the blank was placed in a vacuum sintering furnace, heated to 1220℃ and sintered for 2 hours, then cooled to 1190℃ and held for 3 hours. After cooling in the furnace, a sintered samarium cobalt magnet blank was obtained; the sintered samarium cobalt magnet blank was then placed in an argon atmosphere for a first aging treatment at 840℃ for 50 hours, with a cooling rate of 0.8℃ / min. The blank was then cooled to 400℃ for a second aging treatment for 5 hours, resulting in a sintered samarium cobalt magnet. The concentration of Dy element gradually decreased from the surface to the interior of the magnetic powder, exhibiting a concentration gradient distribution.

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