	US 12,246,475 B2
	Ferrite particles for bonded magnets, resin composition for bonded magnets, and molded product using the same
Yasushi Nishio, Otake (JP); Yasuhiko Fujii, Otake (JP); and Hiromitsu Sakurai, Otake (JP)
Assigned to TODA KOGYO CORP., Hiroshima (JP)
Filed by TODA KOGYO CORP., Hiroshima (JP)
Filed on Oct. 13, 2023, as Appl. No. 18/379,809.
Application 18/379,809 is a continuation of application No. 14/781,777, granted, now 11,820,055, previously published as PCT/JP2014/059641, filed on Apr. 1, 2014.
Claims priority of application No. 2013-078073 (JP), filed on Apr. 3, 2013.
Prior Publication US 2024/0033979 A1, Feb. 1, 2024
Int. Cl. H01F 1/113 (2006.01); B29C 45/00 (2006.01); C01G 49/00 (2006.01); H01F 1/08 (2006.01); H01F 1/11 (2006.01); B29K 505/12 (2006.01); B29L 31/00 (2006.01)

CPC B29C 45/0001 (2013.01) [C01G 49/0036 (2013.01); H01F 1/11 (2013.01); B29K 2505/12 (2013.01); B29L 2031/00 (2013.01); C01P 2004/61 (2013.01); C01P 2006/12 (2013.01); C01P 2006/42 (2013.01)]

16 Claims

1. A process for producing ferrite particles for bonded magnets comprising:

blending and mixing raw material particles at a predetermined mixing ratio to provide mixed raw material particles;

molding the mixed raw material particles by compressing and granulating the mixed raw material particles to provide a molded product, wherein the molding is conducted using a roller compactor;

calcining the molded product at a temperature of 900 to 1250° C. in atmospheric air to provide calcined particles;

subjecting the calcined particles to a pulverization step and washing with water; and then

subjecting the resulting particles to annealing heat treatment at a temperature of 700 to 1100° C. in atmospheric air thereby providing the ferrite particles;

wherein the ferrite particles have a crystallite size of not less than 500 nm as measured in an oriented state by XRD, and an average particle diameter of not less than 1.30 μm as measured by Fisher method.