Tuning the distribution of Tb in Nd-Fe-B sintered magnet to overcome the magnetic properties trade-off
Tuning the distribution of Tb in Nd-Fe-B sintered magnet to overcome the magnetic properties trade-off
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DOI：
10.1016/j.scriptamat.2022.114789
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发表时间：
2022-08
影响因子：
6
通讯作者：
Zhanjia Wang;M. Yue;Weiqiang Liu;Yuqing Li;Haihui Wu;Youhao Liu;S. Zha;X. Yi;Dongtao Zhang-Dongt
中科院分区：
文献类型：
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作者：
Zhanjia Wang;M. Yue;Weiqiang Liu;Yuqing Li;Haihui Wu;Youhao Liu;S. Zha;X. Yi;Dongtao Zhang-Dongt
在现有的晶界扩散（GBD）Nd-Fe-B烧结磁体中，在矫顽力和其他磁性能（剩磁和最大磁能积）之间进行权衡是一个两难的选择。本文报道了一种新的固-液相分离扩散法制备Nd-Fe-B永磁体，该方法可大幅度、全面地提高永磁性能，尤其是退磁曲线的矩形度。结果表明，在液相扩散过程中，Tb通过熔融的富Nd晶界相优先扩散到磁体内部。然后，在随后的固相扩散过程中形成均匀的核壳结构。这种新的GBD策略增加了扩散深度并避免了导致当前GBD磁体磁性能恶化的明显Tb梯度。对比研究了现有工艺和新工艺扩散处理后Nd-Fe-B磁体的微观组织和磁畴演化。
A trade-off between the coercivity and other magnetic properties (remanence and maximum energy product) is a dilemma in current grain boundary diffusion (GBD) Nd-Fe-B sintered magnets. Here we report a new solid-liquid phase separation diffusion method for Nd-Fe-B magnets, which substantially and comprehensively enhances permanent magnetic performance, especially demagnetization curve squareness. The results show Tb diffused preferentially into the inside of magnets through the molten Nd-rich grain boundary phase during the liquid phase diffusion process. Then, uniform core-shell structures were formed during the subsequent solid phase diffusion process. This new GBD strategy increases the diffusion depth and avoids the evident Tb gradient that cause the deterioration of the magnetic performance of current GBD magnets. The microstructure and magnetic domain evolution in the Nd-Fe-B magnets diffused with both current and newly-developed techniques were also compared and investigated.