Coercivity,microstructure,and thermal stability of sintered Nd-Fe-B magnets by grain boundary diffusion with TbH3 nanoparticles

• Published in: Rare metals Vol. 36; no. 9; pp. 718 - 722
• Main Authors: Liu, Wei-Qiang, Chang, Cheng, Yue, Ming, Yang, Jing-Shan, Zhang, Dong-Tao, Zhang, Jiu-Xing, Liu, Yan-Qin
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.09.2017; Springer Nature B.V
• Subjects: Biomaterials; Chemistry and Materials Science; Coercivity; Crystal structure; Energy; Ferrous alloys; Grain boundaries; Grain boundary diffusion; Iron; Magnetic materials; Magnetic properties; Materials Engineering; Materials Science; Metallic Materials; Microstructure; Nanoparticles; Nanoscale Science and Technology; Neodymium; Permanent magnets; Physical Chemistry; Remanence; Sintering; Thermal stability; 显微组织; 晶界扩散; 温度系数; 烧结Nd-Fe-B磁体; 热稳定性; 磁晶各向异性场; 纳米粒子; 高矫顽力; Grain boundary diffusion; nanoparticles; TbH; Thermal stability; Coercivity
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-014-0295-2

Grain boundary diffusion technique with TbH3 nanoparticles was applied to fabricate Tb-less sintered NdFe-B permanent magnets with high coercivity. The magnetic properties and microstructure of magnets were systematically studied. The coercivity and remanence of grain boundary diffusion magnet are improved by 112% and reduced by 26% compared with those of the original magnet, respectively. Meanwhile, both the remanence temperature coefficient（α） and the coercivity temperature coefficient（β） of the magnets are improved after diffusion treatment. Microstructure shows that Tb element enriches in the surface region of Nd2Fe（14）B grains and is expected to exist as（Nd,Tb）2Fe（14）B phase. Thus, the magneto-crystalline anisotropy field of the magnet improves remarkably. As a result, the sintered Nd-FeB magnets by grain boundary diffusion with TbH3 nanoparticles exhibit enhanced coercivity.