烧结钕铁硼晶界扩散矫顽力增强机制研究

Coercivity enhancement of sintered Nd-Fe-B magnet with grain boundary diffusion treatment

高矫顽力烧结钕铁硼磁体具备较强的抗退磁能力和良好的温度稳定性,是保障永磁电机长期安全运转的关键基础。传统制造技术需要在材料中加入大量重稀土元素以提升材料的矫顽力,然而,重稀土元素极为稀缺因而价格高昂,并且重稀土元素直接添加不可避免的会造成材料剩磁的明显下降。本文研究了烧结钕铁硼晶界扩散处理后磁体的微观组织结构变化规律和矫顽力增强机制,通过晶界富稀土相组成及分布的优化,材料矫顽力得到大幅提升,适合制造兼具高剩磁、高矫顽力的高性能钕铁硼永磁材料。

High coercivity sintered Nd-Fe-B magnets with strong resistance to demagnetization and good thermal stability are crucial to ensure the stable long-term operation of permanent magnet motors.Heavy rare earth elements addition has long been used to enhance the coercivity of the sintered Nd-Fe-B magnet.However,low natural abundance of these elements lead to the concerns about high costs.Moreover,excess heavy rare earth elements lead to an inevitable loss of the remanence.In this work,microstructure and coercivity enhancement mechanism of sintered Nd-Fe-B with grain boundary diffusion treatment are studied.Significant coercivity enhancement can be achieved with the optimization of rare-earth rich phases.It can be used for the manufacture of high performance magnets with both high coercivity and high remanence.