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:
Nov. 26, 2019

Filed:

Nov. 02, 2017
Applicants:

Hyundai Motor Company, Seoul, KR;

Kia Motors Corporation, Seoul, KR;

Star Group Ind. Co., Ltd., Daegu, KR;

Inventors:

Jae Ryung Lee, Hwaseong-si, KR;

Dong Hwan Kim, Daegu, KR;

Koon Seung Kong, Daegu, KR;

Assignees:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F 1/057 (2006.01); H01F 41/02 (2006.01); B22F 3/10 (2006.01); B22F 9/04 (2006.01); C22C 1/04 (2006.01);
U.S. Cl.
CPC ...
H01F 1/0577 (2013.01); B22F 3/10 (2013.01); B22F 9/04 (2013.01); C22C 1/0441 (2013.01); H01F 41/0293 (2013.01); B22F 2999/00 (2013.01);
Abstract

Disclosed is a method of producing a rare earth permanent magnet including preparing a NdFeB sintered magnet, coating a surface of the NdFeB sintered magnet with a grain boundary diffusion material including R hydrate or R fluoride, and RMor M, to form a grain boundary diffusion coating layer, and diffusing the grain boundary diffusion material into a grain boundary of the NdFeB sintered magnet by heat treatment, wherein M is a metal having a melting point higher than a heat treatment temperature during the diffusion, R is a rare earth element, and a and b each represent atomic percentages which satisfy the following Equations (1) and (2):0.1<<99.9  (1)=100  (2).


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