US 12,437,917 B2
Method for manufacturing rare earth sintered magnet
Akira Yamada, Echizen (JP); Tetsuya Ohashi, Echizen (JP); and Koichi Hirota, Echizen (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Nov. 1, 2021, as Appl. No. 17/516,232.
Claims priority of application No. 2020-188449 (JP), filed on Nov. 12, 2020.
Prior Publication US 2022/0148801 A1, May 12, 2022
Int. Cl. H01F 41/02 (2006.01); B22F 7/02 (2006.01); B22F 9/04 (2006.01); B22F 9/08 (2006.01); C22C 28/00 (2006.01); H01F 1/057 (2006.01)
CPC H01F 41/0266 (2013.01) [B22F 7/02 (2013.01); B22F 9/04 (2013.01); B22F 9/082 (2013.01); C22C 28/00 (2013.01); B22F 2301/45 (2013.01); C22C 2202/02 (2013.01); H01F 1/0577 (2013.01)] 26 Claims
OG exemplary drawing
 
1. A method for manufacturing a rare earth sintered magnet comprising the steps of:
preparing a plurality of R1-T-X sintered bodies each having a major phase of R12T14X composition wherein R1 is at least one element selected from rare earth elements, and wherein at least one R1 group is Pr or Nd, T is selected from the group consisting of Fe, Co, Al, Ga, and Cu, and wherein at least one T group is Fe, and X is boron and/or carbon, and wherein the plurality of R1-T-X sintered bodies each contains 60 to 99% by volume of the R12T14X composition as the major phase,
forming an alloy powder, which is formed of an alloy containing R2, M and B wherein R2 is at least one element selected from rare earth elements, and wherein at least one R2 group is Dy or Tb, M is at least one element selected from the group consisting of Fe, Cu, Al, Co, Mn, Ni, Sn and Si, and B is boron, the alloy containing 5 to 60 at % of R2, 5 to 70 at % of M, and from more than 20 at % to 70 at % of B,
disposing the alloy powder on the surface of each of the plurality of sintered bodies to obtain a plurality of alloy-covered sintered bodies,
laminate the plurality of alloy-covered sintered bodies to form a laminate,
heat treating the laminate in vacuum or inert gas atmosphere at a temperature not higher than a sintering temperature of the plurality of sintered bodies, and
separating each of the alloy-covered sintered bodies from the laminate.