Title:
RARE EARTH MAGNET POWDER AND PRODUCTION METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2023/119612
Kind Code:
A1
Abstract:
The present invention provides a production method for a rare earth magnet powder that is capable of stably exhibiting high magnetic properties even in a corrosive environment. The present invention is a production method for obtaining a rare earth magnet powder constituted by magnet particles that have a coating film including P, O, and Fe, said production method comprising a treatment step for bringing magnet particles containing Nd, Fe, and B, into contact with a treatment solution containing phosphoric acid ions, and a firing step for heating the magnet particles after the treatment step at 250-350°C. The content ratio (Nd/Fe), which is the atomic ratio of Nd with respect to Fe in the coating film, is, for example, not more than 0.5 in the range (outermost region) from the outermost surface of the coating film to a depth of 10 nm. The coating film may be dense, with no prominent voids etc. near the surface thereof. A bonded magnet using such a rare earth magnet powder is suitable, for example, as a field source for a pump motor to be used in corrosive environments (in water, oil, etc.).
Inventors:
SHIMBA KAZUAKI (JP)
Application Number:
PCT/JP2021/048083
Publication Date:
June 29, 2023
Filing Date:
December 24, 2021
Export Citation:
Assignee:
AICHI STEEL CORP (JP)
International Classes:
B22F9/00; B22F1/00; H01F1/057; H01F1/06
Domestic Patent References:
| WO2008146368A1 | 2008-12-04 | |||
| WO2010071111A1 | 2010-06-24 |
Foreign References:
| JP2011052277A | 2011-03-17 | |||
| JP2018009200A | 2018-01-18 | |||
| JP3882490B2 | 2007-02-14 | |||
| JP3882545B2 | 2007-02-21 | |||
| JP5499738B2 | 2014-05-21 |
Attorney, Agent or Firm:
MORIOKA Masayuki et al. (JP)
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