New grain boundary diffusion strategy of Nd-Fe-B sintered magnets to achieve breakthroughs in Tb-availability and thick limitation
New grain boundary diffusion strategy of Nd-Fe-B sintered magnets to achieve breakthroughs in Tb-availability and thick limitation
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DOI：
10.1016/j.jallcom.2023.169174
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发表时间：
2023-02
影响因子：
6.2
通讯作者：
Zhanjia Wang;Yuqing Li;Haihui Wu;M. Ji;Hongguo Zhang;Weiqiang Liu;M. Yue
中科院分区：
文献类型：
--
作者：
Zhanjia Wang;Yuqing Li;Haihui Wu;M. Ji;Hongguo Zhang;Weiqiang Liu;M. Yue
采用新开发的固-液相分离扩散(SEPD)技术和目前流行的固-液同时扩散(SIMD)技术制备了晶界扩散(GBD)NdFeB烧结磁体。然后用这两种方法研究了不同Tb含量的扩散磁体的磁性能、微观结构和磁畴形态。与使用0.50wt%Tb的SIMD磁体相比，使用0.25wt%Tb的SEPD磁体显示出类似的矫顽力和更强的最大能量积，显示出高Tb利用率。此外，利用新的扩散技术，Tb可以更深地扩散到磁体中，并更均匀地分布在Nd2Fe14B晶体的表面区，形成关键的核-壳结构，而不会在磁体的表面积上产生不良的富集物。结果表明，方形系数由现有工艺扩散磁铁的0.842显著提高到厚度为8 mm的新工艺扩散磁铁的0.925。
Grain boundary diffusion (GBD) Nd-Fe-B sintered magnets were prepared using a newly developed solid-liquid phase separation diffusion (SepD) technique, as well as a currently popular solid-liquid phase simultaneous diffusion (SimD) technique. The magnetic properties, microstructures, and magnetic domain morphologies of the magnets with different Tb contents diffused using the two techniques were then investigated. A SepD magnet using 0.25 wt% Tb exhibited a similar coercivity and a stronger maximum energy product compared to a SimD magnet with 0.50 wt% Tb, demonstrating high Tb availability. Moreover, by using the new diffusion technique, Tb could diffuse deeper into the magnet and distribute more homogeneously around the surface region of the Nd2Fe14B crystal grains, forming the crucial core-shell structure without undesirable enrichment in the surface area of the magnet. As a result, the squareness factor increased noticeably from 0.842 for the current technique diffused magnet to 0.925 for the new technique diffused magnet with a thickness of 8 mm.