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:
Apr. 09, 2019
Filed:
Dec. 22, 2014
Tdk Corporation, Tokyo, JP;
Yoshinori Fujikawa, Tokyo, JP;
Yuki Nagamine, Tokyo, JP;
Wakako Okawa, Tokyo, JP;
Chikara Ishizaka, Tokyo, JP;
Eiji Kato, Tokyo, JP;
Katsuo Sato, Tokyo, JP;
TDK CORPORATION, Tokyo, JP;
Abstract
The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the main phases and the crystal boundary phases among the RTB crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 25 to 35% for R, 60 to 70% for T and 2 to 10% for M.