Abstract Grain boundary diffusion process (GBDP) of Tb on sintered Ce-substituted Nd-Fe-B magnets has been conducted by magnetron sputtering deposition of Tb film for coercivity enhancement. The microstructure and magnetic properties of the diffused (Nd,Ce)FeB magnets have been evaluated and the effect of diffusion temperature, time and Tb coating thickness on the Ce-substituted N35 magnets are discussed. The results show that a core-shell structure is formed around the main grains after GBDP, which promotes the coercivity enhancement of the magnets. A maximum coercivity enhancement from 10.9 kOe to 15.2 kOe is achieved in Ce-N35 magnets by deposition of 10 μm Tb films followed by diffusion processing at 900 °C for 300 min. The inhibition effect of Ce in GBDP of Tb is also evaluated using (Nd,Ce)FeB magnets with different Ce contents and discussed using diffusion model simulation implemented by Tb distributions through GD-OES. The rare earth element (REE)-rich nodes located at the triple junction of the grains may attribute to the Tb aggregation and the formation of TbFe2, resulting in the inhibition of further Tb diffusion.

中文翻译：

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Tb晶界扩散提高烧结Ce取代Nd-Fe-B磁体的矫顽力

摘要 通过磁控溅射沉积 Tb 薄膜以增强矫顽力，在烧结 Ce 取代的 Nd-Fe-B 磁体上进行了 Tb 的晶界扩散过程 (GBDP)。已经评估了扩散 (Nd,Ce)FeB 磁体的微观结构和磁性能，并讨论了扩散温度、时间和 Tb 涂层厚度对 Ce 取代的 N35 磁体的影响。结果表明，GBDP后主晶粒周围形成核壳结构，促进了磁体的矫顽力增强。通过沉积 10 μm Tb 薄膜，然后在 900 °C 下扩散处理 300 分钟，在 Ce-N35 磁体中实现了从 10.9 kOe 到 15.2 kOe 的最大矫顽力增强。还使用 (Nd, 具有不同 Ce 含量的 Ce)FeB 磁体，并讨论了使用通过 GD-OES 由 Tb 分布实现的扩散模型模拟。位于晶粒三重结处的富含稀土元素（REE）的节点可能归因于 Tb 聚集和 TbFe2 的形成，从而抑制了 Tb 的进一步扩散。