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. 30, 2009
Filed:
Jul. 19, 2005
Takeshi Sakamoto, Tokyo, JP;
Nobuya Uchida, Tokyo, JP;
Yoshitomo Tanaka, Tokyo, JP;
Yasuyuki Nakayama, Tokyo, JP;
Takeshi Sakamoto, Tokyo, JP;
Nobuya Uchida, Tokyo, JP;
Yoshitomo Tanaka, Tokyo, JP;
Yasuyuki Nakayama, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
A rare earth magnet having excellent corrosion resistance is provided. It has a magnet body () containing a rare earth element, and a protective film () formed on the magnet body (). In the protective film (), a first protective film (), a second protective film () and a third protective film () are laminated in this order from the side of the magnet body (). These are in a polycrystalline state and composed of a metal plated film, for example. The first protective film () and the third protective film () have a smaller mean crystal grain size than that of the second protective film (). Microcrystallization of the first protective film () can improve the density of the interface between the protective film () and the magnet body (), and decrease the number of pinholes.