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1. (WO2013146781) NdFeB-BASED SINTERED MAGNET

Pub. No.:    WO/2013/146781    International Application No.:    PCT/JP2013/058777
Publication Date: Fri Oct 04 01:59:59 CEST 2013 International Filing Date: Wed Mar 27 00:59:59 CET 2013
IPC: H01F 1/057
B22F 3/00
B22F 3/24
B22F 9/04
C22C 33/02
C22C 38/00
H01F 1/08
H01F 41/02
Applicants: INTERMETALLICS CO., LTD.
インターメタリックス株式会社
Inventors: SAGAWA, Masato
佐川 眞人
FUJIMOTO, Naoki
藤本 尚輝
KOMURA, Kazuyuki
紺村 一之
MIZOGUCHI, Tetsuhiko
溝口 徹彦
Title: NdFeB-BASED SINTERED MAGNET
Abstract:
The purpose of the present invention is to provide an NdFeB-based sintered magnet which is less susceptible to irreversible demagnetization under a high-temperature atmosphere or heat-buildup. This NdFeB-based sintered magnet is a magnet which is manufactured by preparing a base material from an NdFeB-based alloy powder through both orientation in a magnetic field and sintering, making Dy and/or Tb adhere to the surface of the base material, and subjecting the resulting base material to grain boundary diffusion treatment to diffuse the Dy and/or Tb into the grain boundaries in the base material, and which is characterized by having a squareness ratio of 95% or more. The NdFeB-based sintered magnet can be manufactured by: using, as the starting alloy, an NdFeB-based alloy in which lamellas of a rare earth-rich phase are dispersed at prescribed intervals nearly uniformly; making the alloy occlude hydrogen; preparing a base material for an NdFeB-based sintered magnet from the resulting alloy in a manner such that the heating for desorbing the occluded hydrogen is not conducted prior to a sintering step; and subjecting the base material to grain boundary diffusion treatment.