	US 12,234,534 B2
	Sintered magnet and production method for sintered magnet
Matahiro Komuro, Tokyo (JP); and Yuichi Satsu, Tokyo (JP)
Assigned to Hitachi, Ltd., Tokyo (JP)
Appl. No. 17/259,253
Filed by Hitachi, Ltd., Tokyo (JP)
PCT Filed Mar. 8, 2019, PCT No. PCT/JP2019/009396 § 371(c)(1), (2) Date Jan. 11, 2021, PCT Pub. No. WO2020/026501, PCT Pub. Date Feb. 6, 2020.
Claims priority of application No. 2018-143675 (JP), filed on Jul. 31, 2018.
Prior Publication US 2021/0272727 A1, Sep. 2, 2021
Int. Cl. C22C 38/00 (2006.01); B22F 3/00 (2021.01); B22F 3/24 (2006.01); H01F 1/057 (2006.01); H01F 41/02 (2006.01)

CPC C22C 38/005 (2013.01) [B22F 3/00 (2013.01); B22F 3/24 (2013.01); H01F 1/0577 (2013.01); H01F 41/0253 (2013.01); B22F 2003/248 (2013.01); B22F 2998/10 (2013.01); C22C 2202/02 (2013.01)]

7 Claims

1. A sintered magnet, comprising:

a grain including:

a main phase containing, as a main component, a compound containing a rare-earth element, iron and boron, and

a diffusion layer provided on a surface of the main phase,

wherein the diffusion layer contains, as a main component, a compound in which a part of the boron constituting the compound of the main phase is substituted with at least one of carbon and nitrogen,

a concentration of the at least one of the carbon and the nitrogen in the diffusion layer is higher than that in the main phase,

the at least one of the carbon and the nitrogen exhibits a concentration gradient from a surface toward an interior of the grain, and

a ratio X/Y of a concentration X of at least one of the carbon and the nitrogen to a concentration Y of the boron in the diffusion layer is 0.1 or more and 10 or less based on an atomic mass.