Sn对烧结钕铁硼合金高温磁性能的影响及机制分析

Effect of Sn on stability of magnetic properties of NdFeB at elevated temperature and analysis of mechanism

研究了Sn对三元NdFeB合金和含Dy、Al的钕铁硼合金高温磁性能的影响 .发现添加Sn在所有成分系统中 ,都能显著降低磁通不可逆损失 .但是 ,Sn只对含Dy合金的矫顽力热稳定性有明显改善作用 .从微磁学角度分析表明 ,对于三元NdFeB合金 ,不可逆损失减小的原因是Sn改善了显微组织 ,从而降低了合金内部的局部退磁场 .而对于含Dy的合金 ,掺杂Sn使局部退磁场减小及矫顽力热稳定性改善 ,两者都对磁通不可逆损失降低有贡献 .NdDyFeBSn合金矫顽力热稳定性改善的根本原因 ,仍然是局部有效退磁因子因掺杂Sn而减小 .

Magnetic properties of sintered NdFeB with addition of Sn, Dy and Al were investigated with VSM and hysteresisograph at various temperatures. Irrevesible losses of magnetic flux are reduced apparently by doping with Sn. However, only coercivity stabilities of alloys doped with Sn are improved. After analyzing with micromagnetic model, we find the reduction of effective demagnetization factor for NdFeBSn results in decrement of its Lirr. As for alloys doped with Sn, both reduction of N eff and improvement of coercivity stability contribute to decremetn of magnet′s Lirr. Essentially, the improvement of coercivity stability of NdDyFeBSn benefits from reduction of N eff .