磁控溅射法渗铽对烧结钕铁硼磁体性能和结构的影响

Effect of Grain Boundary Diffusion with Sputtering Tb on Properties and Microstructure of Sintered Nd-Fe-B Magnet

对烧结钕铁硼磁体进行渗铽处理,可以让晶体的结构得到改善,使得钕铁硼磁体的矫顽力得到提升,从而提高钕铁硼材料在高温环境使用下的稳定性。本文介绍的磁控溅射法,首先在磁体表面沉积一层金属铽膜,然后通过高温作用,使得铽金属在磁体内部发生晶界扩散,与原有的钕元素发生替换,最终分布于晶粒附近区域和形核外延层。其中,晶界的钕相连续分布在主相周围,起到了去磁耦合作用;扩散到形核外延层的铽则形成了新的壳体结构,可以提高主相晶粒和晶界附近区域的各向异性场并阻止反磁化核的形成,最终提升磁体材料的矫顽力,而且剩磁无明显降低。

Sintered NdFeB magnets through Tb element diffusion into grain boundary,the microstructure can be improved and the coercivity of the magnets will increased,so as to enhance the stability of NdFeB materials in high temperature environment.The magnetron sputtering will introduced in this paper,deposit terbium film on the surface of the magnet,and after heat treatment,the Tb metal diffuse into the magnet,replaces with the original Nd,finally distributes in the area of the grain boundary and the outer region of NdFeB grains.The grain boundary phases are continuously distributed around the main phase grains,which plays a demagnetizing coupling role;the new microstructure of the outer region of NdFeB grains conducive to inhibit the formation of anti-magnetic core and improve the material anisotropy and intrinsic coercivity,finally the coercivity increased significantly and remanence decreased slightly.