Effect of DyHx addition on the elemental distribution, magnetization reversal and coercivity in sintered Nd-Fe-B magnets
Effect of DyHx addition on the elemental distribution, magnetization reversal and coercivity in sintered Nd-Fe-B magnets
复制标题
添加 DyHx 对烧结 Nd-Fe-B 磁体中元素分布、磁化反转和矫顽力的影响
DOI：
10.1088/2053-1591/ab5b21
复制
发表时间：
2019
影响因子：
2.3
通讯作者：
Xue-feng Zhang
中科院分区：
文献类型：
--
作者：
Zhu-bai Li;Yuan Qin;Yun Li;Yan-li Liu;Xue-feng Zhang
Nd 12.2 Fe 81.8 B 6 powders were mixed with DyH x powders to prepare sintered magnets for improving the coercivity. The addition of 1 wt% DyH x leads to a significant increase of coercivity from 7.2 kOe to 12.4 kOe, and for 3 wt% DyH x addition the coercivity increases to 17.1 kOe. However, with increasing the addition amount of DyH x the increasing trend of coercivity becomes slower, and the remanence decreases in the sintered magnets. The activation size is a little larger than the theoretical value of domain wall size in Nd–Fe–B, implying that the reversed domain wall involves the defect region at grain outer-layer that promotes the nucleation of reversed domain wall in the interior of grain. Dy atoms prefer to diffuse into Nd–Fe–B and substitute for Nd due to the theomodynamics origin. For 1 wt% DyH x powders addition some of Dy atoms could diffuse into the outer-layer of main phase, which may modify the grain boundary structure and form (Nd, Dy)–Fe–B shell regions. So the nucleation field of reversed domain is improved at the grain outer-layer, and the coercivity increases largely in the sintered magnets. For more amount addition of DyH x powders, most of Dy atoms enter into the interior of Nd–Fe–B phase. The effect of enhancing the magnetocrystalline anisotropy at the grain outer-layer would be weakened, which should be responsible for the decrease of increasing amplitude of coercivity. Optimizing the addition amount of Dy alloys and regulating the elemental distribution are necessary to balance the coercivity, the remanence and energy product in the sintered magnets.
