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Title:
HIGHLY CORROSION-RESISTANT RARE EARTH PERMANENT MAGNET AND PROCESS FOR PRODUCING THE SAME
Document Type and Number:
WIPO Patent Application WO/2008/020467
Kind Code:
A1
Abstract:
This invention provides a highly corrosion-resistant rare earth permanent magnet. The rare earth permanent magnet comprises an R-T-B-base or R-T-B-M-base permanent magnet produced by hot compaction of an R-T-B-base or R-T-B-M-base magnet powder subjected to dehydrogenation/recombination treatment by a method comprising heating the R-T-B-base or R-T-B-M-base magnet powder in a hydrogen atmosphere to conduct hydrogenation/phase decomposition and then conducting vacuum drawing in the heated state, and a protective film of a composite oxide (R, Fe)2O3, composed mainly of R and Fe, formed on the surface of the permanent magnet, wherein R represents a Y-containing rare earth element; T represents Fe or a component obtained by replacing a part of Fe with Co; M represents one or at least two of Si, Ga, Zr, Nb, Mo, Hf, Ta, W, Al, Ti, and V; and B represents a boron element.

Inventors:
MORIMOTO, Koichiro (3-1-1 Kogane-cho, Niigata-sh, Niigata 40, 9508640, JP)
Application Number:
JP2006/316003
Publication Date:
February 21, 2008
Filing Date:
August 14, 2006
Export Citation:
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Assignee:
MITSUBISHI MATERIALS PMG CORPORATION (3-1-1, Kogane-cho Niigata-sh, Niigata 40, 9508640, JP)
三菱マテリアルPMG株式会社 (〒40 新潟県新潟市小金町3-1-1 Niigata, 9508640, JP)
International Classes:
B22F1/00; B22F3/24; C22C38/00; H01F1/053; H01F1/08; H01F7/02; H01F41/02
Attorney, Agent or Firm:
SHIGA, Masatake et al. (2-3-1, YaesuChuo-ku, Tokyo53, Tokyo1048453, JP)
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