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EP-4379755-B1 - SAMARIUM-BASED RARE EARTH PERMANENT MAGNET MATERIAL, AND PREPARATION METHOD THEREFOR AND APPLICATION THEREOF

EP4379755B1EP 4379755 B1EP4379755 B1EP 4379755B1EP-4379755-B1

Inventors

  • LI, YUPING
  • SUN, Yongyang
  • JIANG, YUNTAO
  • ZHANG, Yunyi
  • GUO, Changzheng

Dates

Publication Date
20260506
Application Date
20230530

Claims (12)

  1. A samarium-based rare-earth permanent magnet material, which has a composition in an atomic ratio: Sm 2 Fe α Cu β V γ Mo δ N ε , wherein 11.5 ≤ α ≤ 17.5, 0.1 ≤ β ≤ 0.4, 1.0 ≤ γ ≤ 1.8, 0 ≤ δ ≤ 1.0, and 2.9 ≤ ε ≤ 4.0.
  2. A preparation method for the samarium-based rare-earth permanent magnet material according to claim 1, comprising the following steps: (1) mixing a samarium powder, an iron powder, a copper powder, a vanadium powder and a molybdenum powder according to a formula amount, and performing melting and rapid-solidification ingot casting in sequence to obtain an alloy sheet; (2) subjecting the alloy sheet obtained in step (1) to grinding, nitriding and ball-milling in sequence to obtain an alloy powder; and (3) subjecting the alloy powder obtained in step (2) to phosphating and a heat treatment in sequence, and cooling to obtain the samarium-based rare-earth permanent magnet material.
  3. The preparation method according to claim 2, wherein the melting in step (1) is performed at a temperature of 1400-1600 °C.
  4. The preparation method according to claim 2 or 3, wherein the melting in step (1) is performed for a period of 50-70 min.
  5. The preparation method according to any one of claims 2-4, wherein the melting in step (1) is performed in an argon atmosphere.
  6. The preparation method according to any one of claims 2-5, wherein the step of grinding in step (2) is: subjecting the alloy sheet obtained in step (1) to mechanical crushing and jet-mill grinding in sequence to obtain powder particles; preferably, an average particle size of the powder particles is 50-100 µm; preferably, the jet-mill grinding is performed in an argon atmosphere.
  7. The preparation method according to any one of claims 2-6, wherein the nitriding in step (2) comprises a first heat treatment and a second heat treatment which are performed in sequence; preferably, the first heat treatment is: under an ammonia atmosphere, heating to 500-550 °C, and holding the temperature for 4-10 h; preferably, the second heat treatment is: under an argon atmosphere, cooling to 400-450 °C, and holding the temperature for 50-70 min.
  8. The preparation method according to any one of claims 2-7, wherein the ball-milling in step (2) is performed in an argon atmosphere; preferably, an average particle size of the alloy powder in step (2) is 2-4 µm.
  9. The preparation method according to any one of claims 2-8, wherein the step of phosphating in step (3) is: mixing phosphoric acid, a solvent and the alloy powder obtained in step (2), and heating until the solvent is evaporated off to obtain a phosphated alloy powder; preferably, a mass of the phosphoric acid is 2.5-3.5wt% of a mass of the alloy powder in step (2); preferably, a mass ratio of the solvent to the alloy powder in step (2) is (0.8-1.2): 1; preferably, the solvent comprises ethanol; preferably, the heating is performed to a final temperature of 78-82 °C; preferably, the phosphating in step (3) is performed in a nitrogen atmosphere.
  10. The preparation method according to any one of claims 2-9, wherein a final temperature of the heat treatment in step (3) is 140-160 °C; preferably, the heat treatment in step (3) has a temperature holding period of 3.5-4.5 h; preferably, the heat treatment in step (3) is performed in an oxygen-containing atmosphere, and a protective gas of the oxygen-containing atmosphere is nitrogen; preferably, the oxygen-containing atmosphere has an oxygen concentration of 50-100 ppm.
  11. The preparation method according to any one of claims 2-10, comprising the following steps: (1) mixing a samarium powder, an iron powder, a copper powder, a vanadium powder and a molybdenum powder according to a formula amount, and in an argon atmosphere, sequentially performing melting at 1400-1600 °C for 50-70 min and rapid-solidification ingot casting to obtain an alloy sheet; (2) sequentially subjecting the alloy sheet obtained in step (1) to mechanical crushing and jet-mill grinding, nitriding, and ball-milling in an argon atmosphere to obtain an alloy powder with an average particle size of 2-4 µm; an average particle size of powder particles obtained by the jet-mill grinding is 50-100 µm; the nitriding comprises a first heat treatment and a second heat treatment which are performed in sequence; the first heat treatment is: under an ammonia atmosphere, heating to 500-550 °C and holding the temperature for 4-10 h; the second heat treatment is: under an argon atmosphere, cooling to 400-450 °C and holding the temperature for 50-70 min; and (3) sequentially subjecting the alloy powder obtained in step (2) to phosphating, and a heat treatment which is performed to 140-160 °C with a temperature holding period of 3.5-4.5 h in an oxygen-containing atmosphere with an oxygen concentration of 50-100 ppm, and cooling to obtain the samarium-based rare-earth permanent magnet material; the step of phosphating is: in a nitrogen atmosphere, mixing phosphoric acid, a solvent and the alloy powder obtained in step (2), and heating until the solvent is evaporated off to obtain a phosphated alloy powder; a mass of the phosphoric acid is 2.5-3.5wt% of a mass of the alloy powder in step (2); a mass ratio of the solvent to the alloy powder in step (2) is (0.8-1.2): 1.
  12. An application of the samarium-based rare-earth permanent magnet material according to claim 1, wherein the samarium-based rare-earth permanent magnet material is used in the fields of small and special electrical machines, magnetic sensors or audio equipment.

Description

TECHNICAL FIELD Examples of the present application relate to the technical field of magnetic materials, for example, a permanent magnet material, a preparation method therefor and an application thereof, and specifically, a samarium-based rare-earth permanent magnet material, a preparation method therefor and an application thereof. BACKGROUND Neodymium-iron-boron rare-earth permanent magnet materials are widely used in fields of vehicles, household appliances and industrial equipment due to the advantages of superhigh remanence, high coercivity and high magnetic energy product. Samarium-based rare-earth permanent magnet materials, represented by a Sm2Fe17Nx compound, have a higher Curie temperature, higher anisotropy field and similar saturation magnetization compared with the NdFeB permanent magnet materials, and are regarded as having the potential to become a new generation of permanent magnet materials. However, in a case where the temperature is more than or equal to 550°C, the Sm2Fe17Nx compound will be irreversibly decomposed, and the magnetic properties will be greatly reduced. CN105355354A discloses a samarium-iron-nitrogen-based anisotropic rare-earth permanent magnet powder and a preparation method therefor. A 2:17-type main phase providing magnetism is wrapped by a low-melting phase composed of element R and element M2, which can not only accommodate excess rare-earth elements in the alloy without forming a SmFe2 phase or a SmFe3 phase, but also help the 2:17-type main-phase grains to eliminate defects, reduce antiphase boundary nucleation sites and decoupling effect. However, the oxidation resistance and magnetic properties of this magnetic powder are still required to be further improved. CN108994311A discloses a preparation method for an anisotropic high-performance samarium-iron-nitrogen permanent magnet alloy powder by solid salt spray granulation and reduction diffusion method, which comprises steps: preparing and mixing raw materials; performing spray granulation; mixing microspheres obtained in the previous step with calcium particles, and performing a reduction diffusion reaction to obtain a samarium-iron alloy; and performing a nitriding treatment to obtain the product. The samarium-iron-nitrogen permanent magnet alloy powder obtained by spray granulation in this application has high coercivity, but the magnetic powder is difficult to be cleaned with water after the nitriding, which has a great impact on the subsequent granulation, and chloride is adopted in the spray granulation and easy to corrode equipment. CN111403165A discloses a preparation method for a samarium-iron-nitrogen/nano-iron composite bonded permanent magnet. In this method, by using chemical vapor deposition method, a layer of nano-Fe film is coated on the surface of a samarium-iron-nitrogen powder for an oxidation resistant coating treatment, and the powder is subjected to granulation and then injection molding or calendering, mold-pressing and extrusion to prepare the composite bonded magnet. This bonded magnet has a high oxidation resistance but also a complicated preparation process, and the overall magnetic performance of the prepared bonded magnet is poor. In view of shortcomings of the related art, it is urgent to provide a rare-earth permanent magnet material with excellent magnetic properties and a low cost. SUMMARY The following is a summary of the subject described in detail herein. This summary is not intended to limit the protection scope of the claims. An example of the present application provides a samarium-based rare-earth permanent magnet material, a preparation method therefor and an application thereof. By the introduction of vanadium element, copper element and molybdenum element, an intrinsic property and a microstructure of the samarium-based rare-earth permanent magnet material can be adjusted, thereby improving the overall magnetic performance of the samarium-based rare-earth permanent magnet material, and the preparation process is simple and economical. In a first aspect, an example of the present application provides a samarium-based rare-earth permanent magnet material, and the samarium-based rare-earth permanent magnet material has a composition in an atomic ratio: Sm2FeαCuβVγMoδNε, wherein 11.5 ≤ α ≤ 17.5, 0.1 ≤ β ≤ 0.4, 1.0 ≤ γ ≤ 1.8, 0 ≤ δ ≤ 1.0, and 2.9 ≤ ε ≤ 4.0. In the composition Sm2FeαCuβVγMoδNε of the samarium-based rare-earth permanent magnet material, 11.5 ≤ α ≤ 17.5, which can be, for example, 11.5, 12.5, 13.5, 14.5, 15.5, 16.5 or 17.5; however, the α is not limited to the listed values, and other unlisted values within this numerical range are also applicable. In the composition Sm2FeαCuβVγMoδNε of the samarium-based rare-earth permanent magnet material, 0.1 ≤ β ≤ 0.4, which can be, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4; however, the β is not limited to the listed values, and other unlisted values within this numerical range are also applicable. In the composi