Enhancement of coercivity of Nd-Fe-B ultrafine powders comparable to single domain size by grain boundary diffusion process

S. Sugimoto, M. Nakamura, M. Matsuura, Y. Une, H. Kubo, M. Sagawa

研究成果: Conference contribution

抄録

Nd-Fe-B sintered magnets are widely used in many applications. However, for the use in motors for hybrid electric vehicles (HEV), the development of Dy-free or Dy-lean Nd-Fe-B sintered magnets with high coercivity is desirable. Decreasing grain size of the Nd2Fe14B phase is an established method for increasing coercivity of Nd-Fe-B sintered magnets. We decreased the size of jet-milled powder to around 1 mm by helium (He) jet-milling in Dy-free Nd-Fe-B sintered magnets and obtained high coercivity (μ0 HcJ) of 2 T with (BH)max of around 400 kJm-3 [1]. We also succeeded further decrease in the size to 0.3 μm by combining hydrogenation-disproportionation-desorption-recombination (HDDR), hydrogen decrepitation (HD) and He jet-milling [2, 3]. However, the effect of annealing on magnetic properties of the ultrafine powders was not clear. On the other hand, the grain boundary diffusion (GBD) process [4-6] is well known as an effective method for the enhancement of coercivity. However, the effect for the ultrafine powders has not been investigated. Therefore, in this investigation, we investigated the effects of annealing and GBD process on coercivity of the Nd-Fe-B ultrafine jet-milled powders prepared by our developed process which combined HDDR, HD and He jet-milling.

本文言語English
ホスト出版物のタイトル2015 IEEE International Magnetics Conference, INTERMAG 2015
出版社Institute of Electrical and Electronics Engineers Inc.
ISBN(電子版)9781479973224
DOI
出版ステータスPublished - 2015 7月 14
イベント2015 IEEE International Magnetics Conference, INTERMAG 2015 - Beijing, China
継続期間: 2015 5月 112015 5月 15

出版物シリーズ

名前2015 IEEE International Magnetics Conference, INTERMAG 2015

Other

Other2015 IEEE International Magnetics Conference, INTERMAG 2015
国/地域China
CityBeijing
Period15/5/1115/5/15

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 電子工学および電気工学
  • 表面、皮膜および薄膜

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