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Magnetic properties and microstructure of high coercivity Zn-bonded Sm-Fe-N magnets

The 10th Pacific Rim International Conference on Advanced Materials and Processing (PRICM10)

2019年8月8日(木)

Masashi Matsuura, Ryo Matsunami, Nobuki Tezuka, Satoshi Sugimoto (Tohoku Univerisity), Tetsuya Shoji, Noritsugu Sakuma (Toyota Motor Corp, MagHEM)

Abstract

 Sm2Fe17N3 has a high saturation magnetization, a large anisotropy field, and a high Curie temperature, however, this compound cannot be sintered because of decomposition above about 600 oC. To obtain high performance Sm-Fe-N bulk magnet, Zn-bonded Sm-Fe-N magnets is expected. Our group prepared Zn-bonded Sm-Fe-N magnets using Zn fine powder with low oxygen content (d50= 0.23 m, oxygen content= 680 ppm), and the low oxygen Zn-bonded Sm-Fe-N magnets showed high coercivity of 2.66 MA/m (15 wt% Zn) [1].
In this study, we investigated relationship between microstructure and coercivity. In magnets without Zn, coercivity decreased and there were -Fe grains at the surface of Sm-Fe-N powder after annealing. However, in high coercive Zn-bonded magnets, Zn-diffused layer existed between the Fe-rich and Sm2Fe17N3 phases after annealing. This indicates that the Zn-diffused layer isolates Sm2Fe17N3 phase from soft magnetic phase (Fe-rich phase), therefore the magnetic isolation can induce high coercivity.
[1]M. Matsuura et al, J. Magn. Magn. Mater., 452 (2018) 243-248.

その他特記事項

This work was partially supported by the Future Pioneering Program “Development of magnetic material technology for high-efficiency motors” commissioned by the New Energy and Industrial Technology Development (NEDO), Japan, and the Elements Strategy Initiative Center for Magnetic Materials (ESICMM) under the outsourcing project of MEXT, Japan.


研究活動

文部科学省

文部科学省
元素戦略プロジェクト(活動紹介)
NIMS磁石パートナーシップ

元素戦略拠点

触媒・電池元素戦略拠点
触媒・電池元素戦略研究拠点 (京都大学)
東工大元素戦略拠点
東工大元素戦略拠点 (東京工業大学)
構造材料元素戦略研究拠点
構造材料元素戦略研究拠点 (京都大学)
高効率モーター用磁性材料技術研究組合
高効率モーター用 磁性材料技術研究組合