Abstract The grain boundary diffusion (GBD) technology was used to prepare high performance Nd-Fe-B sintered magnets by NdH3 and TbH3 nanoparticle diffusion. The factors affecting the coercivity of GBD magnets include distribution of rare earth rich grain boundary phase and substitution of the heavy rare earth. In order to distinguish the influence of various factors on the coercivity, the microstructure and magnetic domain evolution of the original, reference, Nd-diffused, and Tb-diffused magnets were analyzed. The core-shell structure formed by heavy rare earth substitution is the main factor of coercivity enhancement, and it can transform the magnetic domain reversal mode from easy-nucleation (EN) to difficult-nucleation (DN). With increasing of the diffusion depth, the shell of the core-shell structure gradually becomes thinner, DN grains gradually decrease while the EN grains gradually increase, indicating that the magnetic domain reversal mode is directly related to the core-shell structure.

中文翻译：

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晶界扩散钕铁硼烧结磁体矫顽力增强机理的磁畴演化观察

摘要 采用晶界扩散(GBD)技术，通过NdH3和TbH3纳米颗粒扩散制备高性能Nd-Fe-B烧结磁体。影响GBD磁体矫顽力的因素包括富稀土晶界相的分布和重稀土的替代。为了区分各种因素对矫顽力的影响，分析了原始、参考、Nd扩散和Tb扩散磁体的微观结构和磁畴演变。重稀土取代形成的核壳结构是矫顽力增强的主要因素，它可以将磁畴反转模式从易成核（EN）转变为难成核（DN）。随着扩散深度的增加，核壳结构的壳层逐渐变薄，