LiF与TbF3二元系晶界扩散改善Nd-Fe-B磁性能研究

Nd-Fe-B magnetic properties modified by grain boundary diffusion method of LiF and TbF3 mixed binary system

采用LiF和TbF3混合二元系作为扩散源,通过晶界扩散法研究了不同厚度钕铁硼磁体扩散后磁性能变化规律。结果表明,在最优扩散条件下,6 mm磁体的矫顽力从1.05×106 A/m提高到1.71×106 kA/m,10 mm磁体从1.05×106 A/m提高到1.52×106 A/m,且退磁曲线仍具有较高的方形度,剩磁与磁能积也没有显著的降低。SEM图像表明,晶界扩散与表面扩散的共同作用,影响重稀土元素Tb和晶界相在磁体内部的分布,从而使磁体的矫顽力获得较大幅度的提升。

Using the LiF and TbF3 mixed binary systems as diffusion source, the magnetic properties of Nd-Fe-B magnets with different thickness after grain boundary diffusion were studied. The results showed that under the optimum diffusion condition, the coercivity of 6 mm magnets increased from 1.05×106 to 1.71×106 A/m and that of 10 mm magnets increased from 1.05×106 to 1.52×106 A/m. The demagnetization curves still had a high square degree, and the remanence and magnetic energy product were not apparently reduced. From SEM images demonstrated that grain boundary diffusion and surface diffusion jointly affected the distribution of heavy rare earth element Tb in the magnet, which was the reason why the magnets gained a great coercivity increment.