Application of TbF3 Nano-powders by sand milling process in preparing high performance grain boundary diffusion Nd-Fe-B magnets

• Published in: Materials today communications 2024-12, Vol.41, p.110728, Article 110728
• Main Authors: Ji, Ming, Liu, Weiqiang, Wang, Zhanjia, Fan, Min, Wu, Haihui, Du, Ruihua, Li, Yuqing, Zhang, Dongtao, Song, Jie, Wang, Gang, Yi, Xiaofei, Liu, Youhao, Zha, Shanshun, Yue, Ming
• Format: Article
• Language: English
• Subjects: Electrophoretic deposition; Grain boundary diffusion; Nd-Fe-B magnets; Sand Milling; TbF3
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2024.110728

The Electrophoretic deposition grain boundary diffusion (EPD-GBD) technology for sintered Nd-Fe-B magnets has garnered significant attention. In this study, TbF3 nano-powders were synthesized via sand milling (SM) process, and the optimal processes were subsequently explored. Notably, the SM powders exhibit two morphologies: blocky and flocculent. With prolonged SM time, the proportion of larger blocky powders decreases gradually, while the proportion of smaller flocculent powders increases. The morphology and proportion of the powders significantly impact the EPD rate and the effectiveness of GBD. Higher blocky powders proportion improved diffusion, reducing residual Tb layer and enhancing magnet coercivity. Higher flocculent powders proportion caused cracking, poor diffusion, thicker residual layer, and lower coercivity. However, a high EPD rate was achieved with a high proportion of flocculent powders. Considering both EPD rate and diffusion effect, the SM process at 1500 r/min for 30 minutes was identified as the optimal parameter. The TbF3 nano-powders prepared by these conditions exhibited superior advantage in the EPD process and the coercivity of GBD magnets compared to traditional micron-scale TbF3 powders, demonstrating the benefits of the SM process in the EPD and GBD processes of Nd-Fe-B magnets. [Display omitted]