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:
Nov. 06, 1990
Filed:
Dec. 21, 1989
Atsushi Hamamura, Kyoto, JP;
Takaki Hamada, Takatsuki, JP;
Hiroko Nakamura, Takatsuki, JP;
Tomoyuki Imai, Hiroshima, JP;
Toshiki Matsui, Hiroshima, JP;
Nanao Horiishi, Hiroshima, JP;
Sumitomo Special Metals Co., Ltd., Osaka, JP;
Toda Kogyo Corp., Hiroshima, JP;
Abstract
To obtain an anticorrosive Fe-B-R type permanent magnet; in particular, to reduce deterioration rate of the initial magnetic properties below 10% after the magnet has been kept at 80.degree. C. in 90% relative humidity for 500 hours, the surface of the sintered permanent magnet is coated with metallic coating film layers of at least one noble metal layer and at least one base metal layer disposed on the noble metal layer. Diffusion heat treatment further improves the adhesiveness of the coating film layers.