晶界扩散中Tb对烧结NdFeB磁体微观组织和磁性能的影响

通过晶界扩散技术提升烧结钕铁硼(NdFeB)磁体矫顽力的方法已获得广泛应用，为了研究重稀土磁粉对磁体综合磁性能的影响，本文采用喷涂扩散的方法将重稀土Tb含量为6.0%(质量分数)的磁粉作为复合扩散源的一部分进行晶界扩散并制备了高性能烧结NdFeB磁体。结果表明，当主扩散源占比为60%(质量分数)时，Nd₄₀Tb₆₀对应扩散磁体的矫顽力最高达到21.52 kOe，矫顽力增幅明显。经过微观组织结构和XRD表征分析，重稀土元素Tb沿晶界相扩散进入磁体内部的同时发生了晶格取代反应，可在晶粒表层生成磁晶各向异性场更强的(Nd,Dy/Tb)₂Fe₁₄B硬磁相，显著增强了磁体矫顽力。当主扩散源占比为20%、40%和80%(质量分数)时，Nd₈₀Tb₂₀,Nd₆₀Tb₄₀和Nd₂₀Tb₈₀对应扩散磁体的矫顽力增幅较小，其中Nd₈₀Tb₂₀扩散...

Micro-structure and Magnetic Properties of Sintered NdFeB Magnets With Addition of Tb during Grain Boundary Diffusion

Improving the coercivity of sintered NdFeB magnets through grain boundary diffusion technology has been widely used. In order to study the effect of magnetic powder diffusion source containing heavy rare earth metals on the comprehensive performance of NdFeB magnets, the composite diffusion source containing magnetic powder was used, in which the mass proportion of Tb was 6.0%. The mass proportion of the magnetic powder in the composite diffusion source were 20%, 40%, 60%, and 80%, respectively. The results show that when the mass proportion of the main diffusion source (magnetic powder) is 60%, the maximum coercivity of the diffused magnet, Nd40Tb60, reaches 21.52 kOe, which realized a significant increment. After analysis by micro-structure and XRD characterization, it was found that the heavy rare earth of Tb diffused into the interior of the magnet through the grain boundary phase, which also resulted in the lattice substitution reaction. The formation of (Nd, Dy/Tb)2Fe14B phase with stronger magnetic crystal anisotropy field, significantly enhanced the coercivity of the magnet. The coercivity of the diffused magnets, Nd80Tb20, Nd60Tb40 and Nd20Tb80 were weakly improved, in which the coercivity of Nd80Tb20 was 19.60 kOe and the mass proportion of the main diffusion source were 20%, 40%, and 80%, respectively.