富镧铈多主相热变形RE-Fe-B磁体的微结构调控及磁硬化机制研究

热变形纳米晶RE-Fe-B磁体具有磁性能优、抗腐蚀性强及热稳定性高等优点。本项目针对高丰度稀土元素La及Ce在稀土永磁中利用率低的不足，基于高丰度稀土元素Ce的反常磁性能增加效应和晶间相矫顽力增强效应，拟通过原始成分设计优化、低熔点晶间相添加和晶界扩散改性，制备出具有较高高丰度稀土元素含量、高矫顽力和高性价比的多主相热变形RE-Fe-B磁体。厘清稀土元素La、Ce、Pr、Nd及微量掺杂元素Co、Al、Ga、Cu等在致密化烧结、热变形及晶界扩散过程中的冶金偏聚行为。探明原始成分设计-制备工艺-相分离行为-磁性能的内在关系。阐明影响回复曲线张开程度的关键因素，揭示相关物理机制。结合微磁模拟、磁性测量和微结构表征，明确富镧铈多主相热变形RE-Fe-B的磁硬化机制。项目的开展将有利于促进高丰度稀土元素在稀土永磁中的平衡应用。

Hot deformed RE-Fe-B magnets have attracted much attention due to the excellent magnetic properties, strong corrosion resistance, and high thermal stability, etc. Based on the low utilization of La and Ce in the permanent magnets, in this project, hot deformed RE-Fe-B magnets with La/Ce-rich rare-earth elements, high coercivity, and high cost-effectiveness, will be prepared by original composition optimization, the addition of low melting-point intergranular phase, and grain boundary diffusion processes (GBDP). The metallurgical segregation behavior of rare-earth elements (La, Ce, Pr, Nd) and trace doping elements (Co, Al, Ga, Cu, etc.) in the sintering, hot deformation, and grain boundary diffusion processes, will be studied in details. The correlation of phase separation behavior, magnetic properties, microstructure, and preparation processes will be investigated. The key factors affecting the open degree of recoil loops will be clarified, and the related physical mechanism will be revealed. Based on the micromagnetic simulation, magnetic test, and microstructure characterization, the magnetic hardening mechanism will be clarified. The research results will promote the balance use of high abundance rare-earth elements in the rare-earth permanent magnets.