US 12,394,546 B2
Method for producing magnet powder and sintered magnet produced by the same
Jinhyeok Choe, Daejeon (KR); Soon Jae Kwon, Daejeon (KR); Hyounsoo Uh, Daejeon (KR); Kwang Won Jeon, Daejeon (KR); Seung Ho Moon, Yuseong-gu Daejeon (KR); and Jakyu Chun, Daejeon (KR)
Assigned to LG Chem, Ltd., Seoul (KR)
Appl. No. 17/616,518
Filed by LG Chem, Ltd., Seoul (KR)
PCT Filed Jul. 6, 2020, PCT No. PCT/KR2020/008768
§ 371(c)(1), (2) Date Dec. 3, 2021,
PCT Pub. No. WO2021/025301, PCT Pub. Date Feb. 11, 2021.
Claims priority of application No. 10-2019-0094474 (KR), filed on Aug. 2, 2019.
Prior Publication US 2022/0238264 A1, Jul. 28, 2022
Int. Cl. H01F 1/057 (2006.01)
CPC H01F 1/0573 (2013.01) [H01F 1/0572 (2013.01); H01F 1/0577 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for producing a magnet powder comprising:
synthesizing a R—Fe—B-based magnet powder by a reduction-diffusion process;
coating an antioxidant film onto a surface of the R—Fe—B-based magnet powder; and
immersing and cleaning the R—Fe—B-based magnet powder in an aqueous solvent or a non-aqueous solvent, and
wherein coating the antioxidant film onto the surface of the R—Fe—B-based magnet powder is performed before immersing and cleaning the R—Fe—B-based magnet powder,
wherein R is Nd, Pr, Dy or Tb,
wherein the antioxidant film includes a compound containing at least one amino group, and
wherein the compound includes at least one selected from the group consisting of ethylene diamine and 2-ethylhexyloxy propyl amine.