MANUFACTURING METHOD FOR MAGNETIC POWDER FOR FORMING SINTERED BODY OF RARE-EARTH MAGNET PRECURSOR

WIPO Patent Application WO/2013/054778

A1

　Provided is a manufacturing method for a magnetic powder that forms a sintered body of a rare-earth magnet precursor, whereby fine magnetic powder not including coarse particles in the structure thereof can be accurately and efficiently sorted and magnetic powder having a structure comprising crystal grains of the optimal nanosize can be manufactured.　In the manufacturing method for a magnetic powder (p) that forms a sintered body (S) that is a precursor of a rare-earth magnet, the sintered body (S), which comprises nano-crystalline Nd-Fe-B main phase crystal grains and a grain-boundary phase, is subjected to hot plastic working to impart anisotropy to the sintered body (S), and an alloy for improving coercivity is diffused therein. Molten metal is discharged to a cooling roller (R) to produce a rapidly-quenched ribbon (B). The rapidly-quenched ribbon (B) is pulverized to fall within the particle size range 50μm-1000μm, and magnetic powder within the mass range 0.0003mg-0.3mg is produced. The magnetic powder within said mass range is tested for adhesion to a magnet having a surface magnetic flux density of at most 2mT. The magnetic powder (p) that does not adhere is sorted as the magnetic powder for forming the sintered body (S).

SAKUMA NORITSUGU (JP)
KISHIMOTO HIDEFUMI (JP)
MIYAMOTO NORITAKA (JP)
KATO AKIRA (JP)
MANABE AKIRA (JP)
ICHIGOZAKI DAISUKE (JP)
SHOJI TETSUYA (JP)
HARAKAWA SHOICHI (JP)

PCT/JP2012/076065

April 18, 2013

October 09, 2012

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TOYOTA MOTOR CO LTD (JP)
SAKUMA NORITSUGU (JP)
KISHIMOTO HIDEFUMI (JP)
MIYAMOTO NORITAKA (JP)
KATO AKIRA (JP)
MANABE AKIRA (JP)
ICHIGOZAKI DAISUKE (JP)
SHOJI TETSUYA (JP)
HARAKAWA SHOICHI (JP)

H01F41/02; B22F1/00; C22C33/02; C22C38/00; H01F1/057; H01F1/08

JP2010114200A	2010-05-20
JPS6415317A	1989-01-19
JPH06154646A	1994-06-03
JP2011159733A	2011-08-18
JP2011100881A	2011-05-19

KEIKO HIOKI ET AL.: "Cho Kyurei Funmatsu o Genryo to shita Sho-Dy-gata Nd-Fe-B-kei Netsukan Kako Jishaku no Kaihatsu", SOKEIZAI, vol. 52, no. 8, 20 August 2011 (2011-08-20), pages 19 - 24, XP008170756
See also references of EP 2767992A4

HIRAKI Yusuke et al. (JP)
Yusuke Hiraki (JP)

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