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:
Dec. 09, 2008
Filed:
Jun. 24, 2004
Tetsuya Hidaka, Tokyo, JP;
Hironari Okada, Tokyo, JP;
Kazuya Sakamoto, Tokyo, JP;
Takeshi Sakamoto, Tokyo, JP;
Yasuyuki Nakayama, Tokyo, JP;
Tomomi Yamamoto, Tokyo, JP;
Tetsuya Hidaka, Tokyo, JP;
Hironari Okada, Tokyo, JP;
Kazuya Sakamoto, Tokyo, JP;
Takeshi Sakamoto, Tokyo, JP;
Yasuyuki Nakayama, Tokyo, JP;
Tomomi Yamamoto, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
An R-T-B system permanent magnetcomprises a magnet bodycomprising a sintered body comprising at least a main phase comprising RTB grains (wherein R represents one or more rare earth elements, and T represents one or more transition metal elements including Fe or Fe and Co essentially) and a grain boundary phase containing R in a larger amount than the main phase, the magnet bodyhaving a 300 μm or less thick (not inclusive of zero thick) hydrogen-rich layerhaving a hydrogen concentration of 300 ppm or more formed in the surface layer portion, and an overcoatcovering the surface of the magnet bodycan improve the corrosion resistance of the R-T-B system permanent magnetwith an overcoatformed thereon without degrading the magnetic properties thereof. The present invention can be applied to formation of the overcoatby electrolytic plating, can fully ensure the corrosion resistance as a primary target of the overcoatformation without substantially degrading the production efficiency, and can provide the R-T-B system permanent magnetwith a high dimensional precision by suppressing the partial collapse (detachment of grains) of the surface thereof.