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Title:
METHOD FOR PRODUCING R-T-B SINTERED MAGNET
Document Type and Number:
WIPO Patent Application WO/2016/121790
Kind Code:
A1
Abstract:
[Problem] To provide a method for producing an R-T-B sintered magnet, having an excellent HcJ temperature coefficient, a minimal drop in HcJ at high temperatures, and with which it is possible to obtain a high HcJ. [Solution] A method for producing an R-T-B sintered magnet, comprising: a step in which an R-T-B sintered magnet material containing 29.5-35.0 mass% R, 0.80-0.90 mass% B, 0.1-0.8 mass% Ga, 0-2 mass% M, with the remainder being made up of T and unavoidable impurities is prepared; an RH diffusion step in which an RH diffusion source containing the heavy rare earth element RH and the R-T-B sintered magnet material are heated, and the heavy rare earth element RH is diffused in the R-T-B sintered magnet material from the RH diffusion source; a high-temperature heat-treatment step in which the R-T-B sintered magnet which has been subjected to the RH diffusion step is heated to a high temperature of 730-1020°C, and subsequently cooled to 300°C at a rate of at least 5°C/minute; and a low-temperature heat-treatment step in which the R-T-B sintered magnet having undergone the high-temperature heat-treatment step is heated to a temperature of 440-550°C.

Inventors:
Kuniyoshi Futoshi (Hitachi MetalsLtd. 2-15-17, Egawa, Shimamoto-ch, Mishima-gun Osaka 13, 〒6180013, JP)
Application Number:
JP2016/052262
Publication Date:
August 04, 2016
Filing Date:
January 27, 2016
Export Citation:
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Assignee:
HITACHI METALS,LTD. (2-70, Konan 1-chome Minato-k, Tokyo 24, 〒1088224, JP)
International Classes:
H01F41/02; B22F3/24; C21D6/00; C22C38/00; H01F1/057; H01F1/08
Domestic Patent References:
2012-04-05
2011-10-06
Foreign References:
JP2014027268A2014-02-06
JP2007329250A2007-12-20
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