ホーム > 研究活動 > 口頭発表(2018) > Magnetic properties of Mn diffused Sm2Fe17Nx core-shell powder by reduction diffusionprocess

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Magnetic properties of Mn diffused Sm2Fe17Nx core-shell powder by reduction diffusionprocess

The 25th International Workshop on Rare-Earth and Future Permanent Magnets and theirApplications (REPM2018),2018.8.26-30, Beijing,China

2018年8月27日(月)

Masashi Matsuura, Keisuke Yarimizu, Nobuki Tezuka, Satoshi Sugimoto (Tohoku University),Takashi Ishikawa, Yukinobu Yoneyama (Sumiko Kunitomi Denshi, Co. Ltd.)

Abstract

Sm2Fe17Nx compounds have high anisotropy field, Curie temperature and saturation magnetization, thereforethis compound is expected for magnet with high thermal stability. Sm2Fe17Nx based Sm-Fe-N powder withsmall particle size below about 3 m can show high coercivity at room temperature, however coercivitydropped after heating above 150-200℃ . To enhance thermal stability of Sm-Fe-N powder, Mn addition waseffective. Imaoka et al[1] reported that Mn added Sm2(Fe,Mn)17Nx powder (x>3) showed high thermal stabilitywith increasing nitrogen content, however saturation magnetization decreased with increasing nitrogencontent. To achieve high saturation magnetization and high thermal stability simultaneously, Sm2Fe17Nx core- Sm2(Fe,Mn)17Nx shell structure is promising. Thus, the purpose of this study is preparation of Mn-diffusedSm2Fe17Nx core-shell particle by reduction diffusion process. Sm2Fe17 coarse powder, Mn3O4 and Sm2O3powders were pulverized and mixed by ball milling. After Ca grain mixing, the mixed powder was heated abovemelting temperature of Ca. Then, it was heat treated at 400℃ in N2 gas for nitriding, and the nitrided powderwas washed for removing residual Ca and CaO. Magnetic properties of powder was measured by VSM,microstructure was observed SEM and crystal structure was identified by XRD. Figure 1 shows SEM imageand Mn-mapping of Mn-diffused Sm-Fe-N powder prepared in this study. SEM image shows particle size ofSm-Fe-N powder was around 3-5 m, and Mn was enriched at the surface of Sm-Fe-N powder. XRD analysisindicated that crystal structure of the Mn-diffused Sm-Fe-N powder was Th2Zn17 structure. Therefore, it isconsidered that Mn-diffused Sm2Fe17Nx core-shell particle was obtained. Saturation magnetization of thecore-shell powder was higher than that of Sm-Fe-Mn-N powder which was reported in previous studies.

その他特記事項

This study is partially supported by the Elemental Strategy InitiativeCenter 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