烧结钕铁硼中(Al+Cu)含量对晶界扩散的影响  

Influence of (Al+Cu) Content on Grain Boundary Diffusion in Nd-Fe-B Sintered Magnet

作　　者：刘涛[1,2] 张昕 李建[2] 陈杰[2] 程星华 周磊[2] 喻晓军[2] 李波[1] Liu Tao;Zhang Xin;Li Jian;Chen Jie;Cheng Xinghua;Zhou Lei;Yu Xiaojun;Li Bo(Central Iron and Steel Research Institute,Beijing 100081,China;Advanced Technology&Materials Co.,Ltd,Beijing 101318,China)

机构地区：[1]钢铁研究总院,北京100081 [2]安泰科技股份有限公司,北京101318

出　　处：《稀有金属材料与工程》2021年第10期3765-3770,共6页Rare Metal Materials and Engineering

基　　金：安泰科技公司技术创新项目(2019JC0001ZCGN)。

摘　　要：对(Al+Cu)质量分数分别为0.25%和0.5%的钕铁硼基体分别进行Dy晶界扩散,并分析了其矫顽力、Dy含量分布和微观结构。通过比较2种磁体的成分、性能发现,在Dy增加量基本相同的情况下,高(Al+Cu)磁体扩散后的矫顽力提高量相较于低(Al+Cu)磁体高37~44 kA/m。进一步进行成分和矫顽力的梯度分析发现,基体的(Al+Cu)含量变化并没有改变扩散后磁体内部Dy元素随扩散深度的浓度分布,但是矫顽力梯度分析结果显示,高(Al+Cu)样品的各片层矫顽力提升量均比低(Al+Cu)样品各片层高40~80 kA/m。后续的EPMA的Dy面分布图显示,高(Al+Cu)基体扩散后Dy在晶界处富集条纹更清晰、连续,而TEM的EDS分析结果也显示,高(Al+Cu)样品中晶界附近Dy含量更高。(Al+Cu)含量的提高,使得晶界相的流动性增强,Dy更加连续包裹主相晶粒,使得在整体Dy增加量相同的情况下进一步提升矫顽力。Nd-Fe-B base magnets with 0.25wt%and 0.5wt%(Al+Cu)were treated by Dy grain boundary diffusion process and the coercivity distribution,Dy content distribution and microstructure were analyzed.By comparing the composition and properties of the two types of magnets,it is found that the coercivity increment of high(Al+Cu)magnet is 37~44 kA/m higher than that of low(Al+Cu)magnet in spite of the same Dy increment.Further gradient analysis of composition and coercivity shows that the change of(Al+Cu)content does not change Dy distribution versus to the diffusion depth,but the coercivity increments of high(Al+Cu)magnet slices are 40~80 kA/m higher than those of low(Al+Cu)slices.The subsequent EPMA Dy mapping images show that Dy-rich shells are distributed more clearly and continuously at the high(Al+Cu)magnet,and the TEM EDS analysis results also show Dy concentration near the grain boundary region is higher in the high(Al+Cu)magnet.With the increase of(Al+Cu)content,the fluidity of grain boundary phase is enhanced and Dy-rich shell wraps the main phase grains more continuously,which further enhances the coercivity with the same Dy increment.

关 键 词：烧结钕铁硼 晶界扩散 矫顽力 Dy含量 (Al+Cu)含量 

分 类 号：TG174.444[金属学及工艺—金属表面处理] TM272[金属学及工艺—金属学]