Magnetic properties optimization of nanocomposite Nd^sub 9^Fe^sub 85^B^sub 6^ magnets by controlling microstructure of as-quenched ribbons

• Published in: Rare metals 2014-06, Vol.33 (3), p.299
• Main Authors: Liu, Yu-chao, Li, Hong-wei, Li, Kuo-she, Yu, Dun-bo, Jin, Jin-ling, Luo, Yang, Sun, Liang, Quan, Ning-tao
• Format: Article
• Language: English
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-014-0311-6

To optimize the magnetic properties of nanocomposite Nd^sub 9^Fe^sub 85^B^sub 6^ magnets, the as-quenched ribbons with different microstructures were prepared at six wheel velocities from 10 to 30 m·s^sup -1^ through rapid quenching, followed by a series of annealing treatments at 550-800 °C for 5-10 min. It is found that both the large initial grains at low cooling rate and high content of amorphous phase at high cooling rate cause [alpha]-Fe grains coarsening, which leads to a decline in the strength of exchange coupling interaction and the deterioration of magnetic properties. In order to optimize the magnetic properties, the as-quenched ribbons should be chosen with relatively small initial grains as well as a small amount of amorphous phase. For nanocomposite Nd^sub 9^Fe^sub 85^B^sub 6^ materials, the optimized magnetic properties of H ^sub cj^ = 446 kA·m^sup -1^, B ^sub r^ = 0.86 T, (BH) ^sub max^ = 80 kJ·m^sup -3^ are obtained for ribbons prepared at 18 m·s^sup -1^ after annealing at 620 °C for 5 min.[PUBLICATION ABSTRACT]