The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jun. 15, 2021

Filed:

Jan. 31, 2018
Applicant:

Hitachi Metals, Ltd., Tokyo, JP;

Inventor:

Futoshi Kuniyoshi, Minato-ku, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F 41/02 (2006.01); H01F 1/057 (2006.01);
U.S. Cl.
CPC ...
H01F 41/0293 (2013.01); H01F 1/0577 (2013.01);
Abstract

A method of producing a sintered R-T-B based magnet includes providing a sintered R-T-B based magnet work, an RH compound (at least one selected from RH fluorides, RH oxides, and RH oxyfluorides), and an RL-Ga alloy, where the sintered magnet work contains R: 27.5 to 35.0 mass %, B: 0.80 to 0.99 mass %, Ga: 0 to 0.8 mass %, M: 0 to 2 mass % (where M is at least one of Cu, Al, Nb and Zr), and T: 60 mass % or more; a diffusion step of, while keeping the RH compound and the RL-Ga alloy in contact with a surface of the sintered magnet work, performing a first heat treatment between 700° C. and 950° C. to increase the RH amount contained in the sintered magnet work by between 0.05 mass % and 0.40 mass %; and performing a second heat treatment between 450° C. and 750° C. but which is lower than the first heat treatment.


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