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:
Jul. 03, 2001
Filed:
Oct. 21, 1998
Motohisa Hasegawa, Kumagaya, JP;
Takashi Sasaki, Fukaya, JP;
Hitachi Metals, Ltd., Tokyo, JP;
Abstract
An R—T—B-based, permanent magnet with improved resistance to the deterioration of magnetic properties by working, electroplating, etc. and to their change with time, wherein R is one or more of rare earth elements including Y, and T is Fe, part of which may be substituted by Co, has (a) a corrosion-resistant film layer having an average thickness of 5 &mgr;m or more on a surface of a sintered magnet having a composition consisting essentially of 20-45 weight % of R, 15 weight % or less of Co, 0.5-6 weight % of B, and 10 weight % or less of M selected from the group consisting of Al, Si, Nb, Mo, V, Mn, Sn, Ni, Zn, Ti, Cr, Ta, W, Ge, Zr, Hf and Ga, the balance being substantially Fe and inevitable impurities, and (b) a layer richer in rare earth elements than a main phase of R,Fe,B beneath the corrosion-resistant film layer.