	US 12,325,072 B2
	R—Fe—B-based sintered magnet
Akihiro Yoshinari, Echizen (JP); Hiroki Iida, Echizen (JP); Koichi Hirota, Echizen (JP); and Mikio Yoshida, Echizen (JP)
Assigned to Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Appl. No. 17/772,332
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
PCT Filed Nov. 5, 2020, PCT No. PCT/JP2020/041346 § 371(c)(1), (2) Date Apr. 27, 2022, PCT Pub. No. WO2021/095633, PCT Pub. Date May 20, 2021.
Claims priority of application No. 2019-203978 (JP), filed on Nov. 11, 2019.
Prior Publication US 2022/0406498 A1, Dec. 22, 2022
Int. Cl. B22F 3/00 (2021.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); H01F 1/057 (2006.01)

CPC B22F 3/00 (2013.01) [C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/06 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); H01F 1/0577 (2013.01); C22C 2202/02 (2013.01)]

6 Claims

1. An R—Fe—B-type sintered magnet having a composition which consists essentially of from 12.5 to 14.5 at % of R (where R is one or more element selected from the rare-earth elements, with Nd being essential), from 5.0 to 6.5 at % of B, from 0.15 to 5.0 at % of M (where M is one or more element selected from Si, Al, Mn, Ni, Co, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb and Bi), from 0.02 to 0.5 at % of X (where X is one or more element selected from Ti, Zr, Hf, Nb, V and Ta), from 0.1 to 1.6 at % of C and from 0.2 to 0.5 at % of O, with the balance being Fe and inadvertent impurities, and which contains a main phase that is an R₂Fe₁₄B intermetallic compound and a grain boundary phase, wherein the sintered magnet has, in the grain boundary phase, an R-C phase with higher R and C concentrations than the main phase, the areal ratio of the R-C phase in a cross-section of the R—Fe—B-type sintered magnet being greater than 0 and up to 0.5%.