TopPageTopics 2003 > 2003-11


2008/04/07(Mon) 22:00

Coercivity Enhancements by High-Magnetic-Field Annealing
in Sintered Nd-Fe-B Magnets


High-field annealing was performed in sintered Nd-Fe-B magnets in order to increase the coercivity by modifying the interface between the Nd2Fe14B and Nd-rich phases. When the sample, containing 1.3 at.% Dy and 0.32 at.% Al, was annealed at Ta = 823 K under a magnetic field of μ0Ha = 14 T, the coercivity reached 1.92 T, which is 37% higher than that for the control sample annealed at zero field. This result is expected to stimulate higher-temperature applications such as power motors for electric vehicles.

Dept. of Appl. Phys., Tohoku University: H. Kato, T. Miyazaki
Intermetallics Co.: M. Sagawa
IMR, Tohoku University: K. Koyama
Referece: H. Kato, T. Miyazaki, M. Sagawa and K. Koyama, "Coercivity enhancements by
high-magnetic-field annealing in sintered Nd-Fe-B magnets", Appl. Phys. Lett. 84
(2004) 4230 - 4232.

Nd-Fe-B 焼結磁石の主相Nd2Fe14BとNd-rich粒界相の界面構造制御によって保磁力上昇を目指すために,強磁場熱処理を行った.その結果,Dyを1.3 at.%,Alを0.32at.%含む試料について 823 Kで14 Tの磁場を加えながら熱処理した場合の保磁力は1.92 Tと,ゼロ磁場熱処理した参照試料の値に比べて,37%もの向上を示すことが明らかになった.この成果によって,電気自動車や動力モータなどの高温用永久磁石への応用が加速されるものと期待される.

東北大学 大学院工学研究科 応用物理学専攻:加藤宏朗,宮﨑照宣
東北大学 金属材料研究所:小山佳一