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1. (WO2018101239) R-FE-B SINTERED MAGNET AND PRODUCTION METHOD THEREFOR

Pub. No.:    WO/2018/101239    International Application No.:    PCT/JP2017/042535
Publication Date: Fri Jun 08 01:59:59 CEST 2018 International Filing Date: Wed Nov 29 00:59:59 CET 2017
IPC: H01F 1/057
B22F 3/00
B22F 3/24
C21D 6/00
C22C 33/02
C22C 38/00
H01F 41/02
Applicants: SHIN-ETSU CHEMICAL CO., LTD.
信越化学工業株式会社
Inventors: OHASHI Tetsuya
大橋 徹也
HIROTA Koichi
廣田 晃一
NAKAMURA Hajime
中村 元
Title: R-FE-B SINTERED MAGNET AND PRODUCTION METHOD THEREFOR
Abstract:
This R-Fe-B sintered magnet has a main phase containing R2(Fe, (Co))14B intermetallic compound and a grain boundary phase, and is characterized in that: the inter-particle grain boundary of the grain boundary phase includes an expanded width part that is surrounded by a narrow width part at which the inter-particle width is 10 nm or less and that has a structure distended in the inter-particle width direction as compared with the grain boundary width of the narrow width part; the inter-particle width at the expanded width part is at least 30 nm; Fe/R which is the atomic ratio of Fe with respect to R in the expanded width part is 0.01-2.5; the main phase includes, in the surface part thereof, an HR-rich phase represented by (R', HR)2(Fe, (Co))14B (R' represents one or more elements that are selected from rare-earth elements including Y but excluding Dy, Tb, and Ho, and that essentially include Nd; and HR represents one or more elements selected from among Dy, Tb, and Ho); the contained amount of HR in the HR-rich phase is higher than that in the central part of the main phase. The R-Fe-B sintered magnet according to the present invention has a high magnetic coercive force even when the contained amount of Dy, Tb, and Ho is small.