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:
Jun. 08, 2004
Filed:
May. 30, 2001
Kazuo Tamura, Takefu, JP;
Masanobu Shimao, Takefu, JP;
Ryuji Hamada, Takefu, JP;
Takehisa Minowa, Takefu, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
An R—Fe—B permanent magnet wherein R is Nd or a combination of Nd with a rare earth element is prepared by casting an R—Fe—B alloy, crushing the alloy in an oxygen-free atmosphere of argon, nitrogen or vacuum, effecting comminution, compaction, sintering, aging, and cutting and/or polishing the magnet to give a finished surface. The magnet is then heat treated in an argon, nitrogen or low-pressure vacuum atmosphere having a limited oxygen partial pressure, obtaining a highly oil resistant sintered permanent magnet having corrosion resistance and hydrogen barrier property even in a high pressure hot environment of refrigerant and/or lubricant as encountered in compressors.