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.
Patent No.:
Date of Patent:
Mar. 02, 2021
Filed:
Sep. 20, 2017
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Tetsuya Ohashi, Echizen, JP;
Tetsuya Kume, Echizen, JP;
Koichi Hirota, Echizen, JP;
Hajime Nakamura, Echizen, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
An R—Fe—B base sintered magnet is prepared through the steps of providing an alloy fine powder having a predetermined composition, compression shaping the alloy fine powder in an applied magnetic field into a compact, sintering the compact at a temperature of 900-1,250° C. into a sintered body, cooling the sintered body to 400° C. or below, high-temperature heat treatment including placing a metal, compound or intermetallic compound containing HR which is Dy, Tb and/or Ho, on the surface of the sintered body, heating at a temperature from more than 950° C. to 1,100° C., for causing grain boundary diffusion of HR into the sintered body, and cooling to 400° C. or below, and low-temperature heat treatment including heating at a temperature of 400-600° C. and cooling to 300° C. or below. The sintered magnet produces a high coercivity despite a low content of Dy, Tb and Ho.