# US 11,305,345 B2 · Method for preparing neodymium-iron-boron permanent magnetic material

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- Number: US 11,305,345 B2
- Document ID: US11305345B2
- Status: Granted
- Kind: B2
- Application number: 16/472,034
- Filed: 2017-12-21
- Published: 2020-01-02
- Granted: 2022-04-19
- Earliest claimed: 2016-12-21
- Assignees: Baotou Research Institute of Rare Earths; National Engineering Research Centre of Ruike Rare Earth Metallurgy and Function Materials Co., Ltd.; Baotou Iron & Steel (Group) Co., Ltd.; Xiamen Institute of Rare Earth Materials; Baotou Jinshan Magnetic Material Co. Ltd
- Applicants: Baotou Research Institute of Rare Earths; National Engineering Research Centre of Ruike Rare Earth Metallurgy and Function Materials Co., Ltd.; Baotou Iron & Steel (Group) Co., Ltd.; Xiamen Institute of Rare-Earth Materials; Baotou Jinshan Magnetic Material Co. Ltd
- Inventors: Liangcheng Sun; Zhanfeng Yang; Zhihong Zhang; Xiaoyu Liu; Shufeng Liu; Fan Yang; Jixiang Liu; Yu Wang; Jingya Li; Fei Lu; Shupu Lou; Hui Li; Peixin Chen; Yang Bai; Yu Cheng; Feng Wang; Tiancang Zheng; Feng Xia; Caina Sun
- Web page: https://patentgrep.com/patent/US11305345B2

## CPC

- B22F 1/17: Metallic particles coated with metal
- B22F 9/04: starting from solid material, e.g. by crushing, grinding or milling ({C22C1/1084 takes precedence}; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C)
- C23C 14/16: on metallic substrates or on substrates of boron or silicon
- C23C 14/165: {by cathodic sputtering}
- C23C 14/18: on other inorganic substrates
- C23C 14/185: {by cathodic sputtering}
- C23C 14/223: {specially adapted for coating particles}
- C23C 14/35: by application of a magnetic field, e.g. magnetron sputtering {(C23C14/3457 takes precedence)}
- C23C 14/5806: {Thermal treatment}
- C23C 14/5886: {Mechanical treatment (involving removal of material C23C14/588)}
- H01F 1/0577: {sintered}
- H01F 41/0266: {Moulding; Pressing (H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11)}
- H01F 41/0273: {Imparting anisotropy (methods and devices for magnetising permanent magnets H01F13/003)}
- B22F 2301/355: Rare Earth - Fe intermetallic alloys
- B22F 2304/10: Micron size particles, i.e. above 1 micrometer up to 500 micrometer
- C22C 2202/02: Magnetic
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A method for preparing a NdFeB permanent magnetic material may include providing a covered NdFeB magnetic powder by depositing heavy rare earth particles or high-melting particles onto a NdFeB magnetic powder by physical vapor deposition; and performing orientation molding and sintering on the covered NdFeB magnetic powder to provide the NdFeB permanent magnetic material.

## Claims

### Claim 1

A method for preparing a NdFeB permanent magnetic material, the method comprising:
(1) carrying out ingredients-mixing, smelting, strip casting, hydrogen crushing, disproportionation reaction, and jet milling to obtain NdFeB fine powder with an average particle diameter D50 of 1 μm;
(2) placing the NdFeB fine powder and a CoZr thermal resistance wire respectively in a thermal resistance evaporation deposition device with a vacuum degree of 103 Pa; setting parameters so as to uniformly disperse the NdFeB fine powder; heating the CoZr thermal resistance wire to evaporate and deposit CoZr particles on the NdFeB fine powder; taking out the covered NdFeB fine powder after its temperature is decreased to room temperature;
(3) performing orientation molding, sintering, and heat treatment on the covered NdFeB fine powder so as to obtain the NdFeB permanent magnetic material.