Abstract Al film, which was coated in sintered Nd-Fe-B magnets prepared by magnetron sputtering, was employed for grain boundary diffusion source. Effects of the grain boundary diffusion processes (GBDP) on the microstructure evolution and properties were investigated in detail. Through grain boundary diffusion processes, the highest coercivity of 1184 kA/m and maximum energy product of 238 kJ/m3 could be obtained, increasing by 21.8% and 3.9%, respectively, compared with the initial magnet. Meanwhile, our results showed that fine, uniform and continuous intergranular phase induced by Al diffusion, was the main reason for properties improvement, while a weak ferromagnetic phase and the vague interface between main phase and RE-rich phase should be responsible to the deterioration of coercivity when the diffused temperature exceed 600 °C. Besides, the corrosion resistance of Al-diffused magnets was also greatly improved, owing to the fact that the Al element could promote the electrochemical potential of RE-rich phase and the more thin, continuous intergranular phase would also narrow the corrosion channel.

中文翻译：

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非稀土晶界扩散烧结钕铁硼磁体的显微组织和性能改善

摘要 采用磁控溅射法制备烧结Nd-Fe-B磁体，包覆Al薄膜作为晶界扩散源。详细研究了晶界扩散过程 (GBDP) 对微观结构演变和性能的影响。通过晶界扩散过程，可以获得1184 kA/m的最高矫顽力和238 kJ/m3的最大能积，与初始磁体相比，分别提高了21.8%和3.9%。同时，我们的研究结果表明，由 Al 扩散引起的细小、均匀和连续的晶间相是性能改善的主要原因，而弱铁磁相和主相与富稀土相之间的模糊界面应该是造成性能恶化的原因。扩散温度超过 600 °C 时的矫顽力。除了，