Title:
PERMANENT MAGNET AND PROCESS FOR PRODUCING THE SAME
Document Type and Number:
WIPO Patent Application WO/2008/023731
Kind Code:
A1
Abstract:
A process for producing a permanent magnet, in which without deteriorating of
the surface of Nd-Fe-B sintered magnet, Dy is efficiently diffused in the crystal
grain boundary phase to thereby attain effective enhancements of magnetization
intensity and coercive force, and in which post-processes can be avoided. In
treatment chamber (20), Nd-Fe-B sintered magnet (S) and Dy are disposed with
an interspace therebetween. Subsequently, in vacuum, the treatment chamber
(20) is heated so that not only is the temperature of the sintered magnet raised
to a given temperature but also Dy is evaporated to thereby attain supply of evaporated
Dy molecules to the surface of the sintered magnet and adhesion therebetween.
In this stage, the rate of Dy molecules supplied to the sintered magnet is controlled
so that prior to the formation of any Dy layer on the surface of the sintered magnet,
Dy is diffused in the crystal grain boundary phase of the sintered magnet so as
to be uniformly present all over the phase.
Inventors:
NAGATA, Hiroshi (Inc. Tsukuba Institute for Super Materials, 5-9-6 Tokodai, Tsukuba-sh, Ibaraki 35, 3002635, JP)
永田 浩 (〒35 茨城県つくば市東光台５－９－６ 株式会社アルバック 筑波超材料研究所内 Ibaraki, 3002635, JP)
永田 浩 (〒35 茨城県つくば市東光台５－９－６ 株式会社アルバック 筑波超材料研究所内 Ibaraki, 3002635, JP)
Application Number:
JP2007/066272
Publication Date:
February 28, 2008
Filing Date:
August 22, 2007
Export Citation:
Assignee:
ULVAC, INC. (2500, Hagisono Chigasaki-sh, Kanagawa 43, 2538543, JP)
株式会社アルバック (〒43 神奈川県茅ヶ崎市萩園２５００番地 Kanagawa, 2538543, JP)
NAGATA, Hiroshi (Inc. Tsukuba Institute for Super Materials, 5-9-6 Tokodai, Tsukuba-sh, Ibaraki 35, 3002635, JP)
株式会社アルバック (〒43 神奈川県茅ヶ崎市萩園２５００番地 Kanagawa, 2538543, JP)
NAGATA, Hiroshi (Inc. Tsukuba Institute for Super Materials, 5-9-6 Tokodai, Tsukuba-sh, Ibaraki 35, 3002635, JP)
International Classes:
H01F41/02; H01F1/053; H01F1/08
Attorney, Agent or Firm:
Exeo Patent & Trademark Company (2nd Fl, Ebisu Lite Bldg.1-19, Ebisuminami 3-chome, Shibuya-ku Tokyo 22, 1500022, JP)