矫顽力
晶界扩散系数
材料科学
微观结构
粒度
晶界
磁铁
扩散
冶金
有效扩散系数
晶粒生长
扩散过程
间断(语言学)
凝聚态物理
热力学
电气工程
物理
放射科
工程类
数学分析
磁共振成像
医学
知识管理
计算机科学
数学
创新扩散
作者
Shuai Guo,Xiao Yang,Xiaodong Fan,Guangfei Ding,Shuai Cao,Bo Zheng,Renjie Chen,Aru Yan
出处
期刊:Materials
[Multidisciplinary Digital Publishing Institute]
日期:2022-07-18
卷期号:15 (14): 4987-4987
被引量:7
摘要
The grain boundary diffusion process (GBDP) of heavy rare earth Tb is an effective method to improve the coercivity of Nd-Fe-B magnets, and the matrix grain size has a crucial effect on the diffusion efficiency and depth of the Tb element. In this work, magnets with different grain sizes have been fabricated using powder metallurgy to investigate the effect of grain size on Tb diffusion efficiency and the microstructure of Nd-Fe-B-type magnets. After the Tb diffusion process, the coercivity increment of the magnet with 4.9 μm large grain is 8.60 kOe, which is much higher than that of the magnet with 3.0 μm small grain (~5.90 kOe), which clearly demonstrates that the coercivity increment decreases as the grain size decreases. Microstructure analysis suggested that grain refinement significantly increases the total surface area, resulting in narrowing and discontinuity of the grain boundary phase (GBP). Therefore, as the channel for diffusion, the narrowing and discontinuity of the GBP are unfavorable for diffusion, resulting in a decrease in diffusion efficiency.
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