NdFeB磁体的Dy热扩渗过程及其矫顽力提高机制  

Dy Thermal Diffusion Process of NdFeB Magnets and Its Coercive Force Improvement Mechanism

作　　者：刘富刚 赵东 向令 裴文利 LIU Fu-gang;ZHAO Dong;XIANG Ling;PEI Wen-li(School of Materials Science&Engineering,Northeastern University,Shenyang 110819,China;Key Laboratory for Anisotropy and Texture of Materials of Ministry of Education,Northeastern University,Shenyang 110819,China.)

机构地区：[1]东北大学材料科学与工程学院,辽宁沈阳110819 [2]东北大学材料各向异性与织构教育部重点实验室,辽宁沈阳110819

出　　处：《东北大学学报（自然科学版）》2022年第4期517-523,共7页Journal of Northeastern University(Natural Science)

基　　金：国家自然科学基金资助项目(51871045,52071070);中央高校基本科研业务费专项资金资助项目(N2017003).

摘　　要：采用回收料制备的商业35M磁体作为研究对象,使用自制新型DyF_(3)涂料对磁体进行热扩渗处理.研究表明:新型涂料具有速干、附着力好、涂覆均匀的特点,有效改善了热扩渗工艺的稳定性;该磁体经过920℃×10 h的热扩渗处理,获得了良好的综合磁性能,磁体矫顽力提高到1710.2 kA/m,增幅为37.9%.微观结构分析揭示了Dy元素的扩渗过程和磁体矫顽力提高机理.Dy元素沿晶界扩渗,在主相晶粒周围形成了各向异性场更高(Nd,Dy)_(2)Fe_(14)B的富Dy壳层,使晶界富Nd相变得更加连续、清晰,导致磁体矫顽力大幅增加.The commercial 35M magnet prepared from recycled materials was used as the research object,and a self-made new DyF_(3) coating was used to conduct thermal diffusion treatment on the magnets.The results show that the new coating has the characteristics of quick-drying,good adhesion and uniform coating,which effectively improves the stability of thermal diffusion process.The magnet subjected to thermal diffusion treatment at 920℃×10 h,has a good performance on the magnetic properties,where the coercive force of the magnet reaches 1710.2 kA/m with an increase of 37.9%.Microstructure analysis reveals the diffusion process of Dy element and the mechanism of coercive force improvement of the magnet.It is found that Dy element diffuses along the grain boundary and a Dy-rich shell of(Nd,Dy)_(2)Fe_(14) B with a higher anisotropy field can be formed around the grains of main phase,which makes the Nd-rich phase of the grain boundary more continuous and clear,resulting in a substantial increase in the coercive force of the magnet.

关 键 词：NDFEB磁体 晶粒尺寸 晶界扩渗 矫顽力 Dy扩渗过程 

分 类 号：TM273[一般工业技术—材料科学与工程]