RARE-EARTH MAGNETIC POWDER, METHOD FOR MANUFACTURING SAME, AND BOND MAGNET

WIPO Patent Application WO/2023/119908

A1

The present invention provides a method for manufacturing a rare-earth magnetic powder that provides a high magnetic characteristic stably even in a corrosive environment. The method of the present invention comprises a treatment step for contacting magnetic particles containing Nd, Fe, and B with a treatment fluid containing phosphate ion, and a firing step for heating the magnetic particles after the treatment step at 250-350℃. With the method, it is possible to obtain a rare-earth magnetic powder composed of magnetic particles having a coating comprising P, O, and Fe. A content ratio (Nd/Fe), which is the atomic ratio of Nd to Fe contained in the coating, is 0.5 or less, for example, in a range (upper-most region) from the upper-most surface of the coating to a depth of 10 nm. Preferably, the coating is dense without any conspicuous voids and the like near the surface. A bond magnet in which the rare-earth magnetic powder is used is preferable, for example, as a field source for a pumping electric motor for use in a corrosive environment (such as in a water environment or an oil environment).

SHINTAKU MASAYA (JP)
SHIMBA KAZUAKI (JP)

PCT/JP2022/041306

June 29, 2023

November 07, 2022

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AICHI STEEL CORP (JP)

H01F1/057

WO2008146368A1	2008-12-04
WO2010071111A1	2010-06-24

JP2011052277A	2011-03-17
JP2018009200A	2018-01-18
JP3882490B2	2007-02-14
JP3882545B2	2007-02-21
JP5499738B2	2014-05-21

MORIOKA Masayuki et al. (JP)

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