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. 04, 2002
Filed:
May. 10, 2001
Sumitomo Special Metals Co., Ltd., Osaka, JP;
Abstract
An Fe—B—R based permanent magnet has a metal oxide film having a thickness of 0.01 &mgr;m to 1 &mgr;m on its surface with a metal film interposed therebetween. Thus, the film is excellent in adhesion to the surface of the magnet. Even if the permanent magnet is left to stand under high-temperature and high-humidity of a temperature of 80° C. and a relative humidity of 90% for a long period of time, the magnetic characteristic of the magnet cannot be degraded. The magnet has a thermal shock resistance enough to resist even a heat cycle for a long period of time in a temperature range of −40° C. to 85° C., and can exhibit a stable high magnetic characteristic. Therefore, it is possible to produce an Fe—B—R based permanent magnet having a corrosion-resistant film free from hexa-valent chromium.