摘要
研究了晶界扩散处理对高Dy含量烧结Nd-Fe-B磁体性能和结构的影响。经蒸镀渗Dy晶界扩散处理,高Dy含量Nd-Fe-B磁体的矫顽力从1 713 kA/m提高至2 161 kA/m,而剩磁和最大磁能积基本没有下降,处理后磁体内Dy平均质量分数仅增加0.30%。不同深度片层分析表明,虽然磁体近表面片层比中心片层的Dy含量高,但是片层间矫顽力相差较少,而且所有片层的矫顽力均远高于未处理磁体片层的矫顽力。电子探针Dy元素面分布结果显示,在未处理高Dy含量磁体的晶界与主相中均存在Dy元素富集区且富集浓度较低,而经扩散处理后,晶界富Nd相中的Dy富集区浓度及所占比例明显提高;包括磁体芯部在内,磁体内大部分角隅处富Nd相内Dy含量明显增加,进一步提高了高Dy含量磁体内部各处的矫顽力。
Effect of grain boundary diffusion treatment on magnetic properties and structures of sintered Nd-Fe-B magnet with high Dy content was investigated.Using Dy vapor sorption process,the coercivity of high Dy content magnet increases from 1 713 kA/m to 2 161 kA/m without decrement of remanence or maximum energy product.Dy content of the whole magnet merely increased 0.30％ （mass percent） after treatment.Further investigation of the flakes at different depths of magnet reveals that the coercivity of the flakes is similar although the Dy content in subsurface flakes is more than that in central flakes.Moreover,the coervity of all flakes is much higher than untreated ones.According to the EPMA mapping images,Dy is dispersed not only in the grain boundary but also among the main phases,and concentration of Dy-rich area is lower in untreated sample.However,for the treated samples,the concentration and the scale of Dy-rich area in grain boundary are both much larger than those of untreated ones.The coercivity of the flakes at different depth is all greatly increased due to remarkable Dy increase among the most of Nd-rich triple junction grain phases.
出处
《粉末冶金工业》
CAS
北大核心
2014年第5期33-37,共5页
Powder Metallurgy Industry
基金
安泰科技重大技术创新项目(2012JA01GGN)
