Nb对(Nd,Dy)-(Fe,Co)-B永磁体显微组织的影响

EFFECT OF Nb ADDITION ON MICROSTRUCTURE OF (Nd,Dy)-(Fe,Co)-B MAGNETS

用金相显微镜、扫描电镜分析了(Nd,Dy)-(Fe,Co)-B稀土永磁体加入Nb后显微组织的变化.结果表明,加入Nb后出现了板条状Fe_2Nb相和沉淀粒子相,且二者数量均随Nb量增加而增加.烧结时,φ相晶内的Fe_2Nb发生部分固溶,晶界的Fe_2Nb可机械阻碍晶粒长大.在时效时,φ相内固溶的Nb发生沉淀析出,晶界附近固溶的Nb扩散到富Nd相内形成新的含Nb粒子和增加富Nd相内的Nb含量。

An addition of Nb up to 2 at.-％ into (Nd, Dy)-(Fe, Co)-B alloy causes to form the primary lath Fe_2Nb crystallization and to precipitate the hard magnetic grain. Both increases with the increasing Nb content. During sintering, part of Fe_2Nb dissolves within the 2:14:1 phase, and the Fe_2Nb along grain boundary hinders the growth of 2:14:1 grain. In annealing processing, the dissolved Nb in φ phase precipitates out, and this nearby the grain boundary diffuses into Nd-rich phase to form new Nb-containing grain and to increase the Nb content in Nd-rich phase.