Ferromagnetic particles and process for producing the same, anisotropic magnet and bonded magnet

Patent metadata

Field	Value
Publication number	US-2016189836-A1
Application number	US-201615059906-A
Country	US
Kind code	A1
Filing date	Mar 3, 2016
Priority date	Oct 22, 2009
Publication date	Jun 30, 2016
Grant date	—

Abstract

The present invention relates to Fe 16 N 2 particles in the form of a single phase which are obtained by subjecting iron oxide or iron oxyhydroxide whose surface may be coated with at least alumina or silica, if required, as a starting material, to reducing treatment and nitridation treatment, a process for producing the Fe 16 N 2 particles in the form of a single phase for a heat treatment time of not more than 36 hr, and further relates to an anisotropic magnet or a bonded magnet which is obtained by magnetically orienting the Fe 16 N 2 particles in the form of a single phase. The Fe 16 N 2 particles according to the present invention can be produced in an industrial scale and have a large BH max value.

First claim

1 - 9 . (canceled)

10 . A bonded magnet comprising the ferromagnetic particles comprising an Fe 16 N 2 single phase and having a BH max value of not less than 5 MGOe.

11 . The bonded magnet according to claim 10 , wherein the ferromagnetic particles further comprise an Si compound and/or an Al compound with which a surface of the respective Fe 16 N 2 particles is coated.

12 . The bonded magnet according to claim 10 , wherein the ferromagnetic particles have a saturation magnetization value ss of not less than 130 emu/g and a coercive force Hc of not less than 1800 Oe.

13 . The bonded magnet according to claim 10 , wherein the ferromagnetic particles comprise primary particles having an average minor axis diameter of 5 to 40 nm and an average major axis diameter of 30 to 250 nm.

14 . The bonded magnet according to claim 10 , wherein the ferromagnetic particles have a BET specific surface area of 80 to 250 m 2 /g.

Assignees

• Toda Kogyo Corp
• Univ Tohoku

Inventors

• Takahashi Migaku
• Ogawa Tomoyuki
• Ogata Yasunobu
• Kobayashi Naoya

Classifications

• C01P2004/64

  Nanometer sized, i.e. from 1-100 nanometer · CPC title

• H01F1/08

  pressed, sintered, or bound together · CPC title

• C01P2006/12

  Surface area · CPC title

• H01F1/061

  with a protective layer · CPC title

• H01F1/06 Primary

  in the form of particles, e.g. powder (H01F1/047 takes precedence {; record carriers G11B5/70605}) · CPC title