晶界扩散型烧结钕铁硼永磁的磁硬化机理研究

本项目以重稀土晶界扩散烧结钕铁硼永磁的磁硬化机理为研究对象。首先以重稀土氢化物纳米颗粒为扩散源，采用晶界扩散技术制备出微结构可控的重稀土晶界扩散烧结钕铁硼永磁。在此基础上，分析、测定磁体的显微组织、化学成分、磁畴结构及各项磁性能参量。并以微磁学为理论基础，用有限元/有限差分的方法建立与重稀土晶界扩散烧结钕铁硼永磁结构特征相符的理论模型。进一步，深入研究磁体的磁化、反磁化行为对其磁性能的影响。其中重点考查磁体的宏观磁化行为与其微观磁畴结构演化过程的关联性；并考查磁体在反磁化过程中形成磁硬化的详细机制。最终建立重稀土晶界强化型烧结钕铁硼永磁的微结构与磁性能之间的构效关系模型。本研究的结果有望进一步丰富烧结钕铁硼永磁材料的技术磁化理论，同时为研制磁性能优异的新型低重稀土耐高温烧结钕铁硼永磁材料提供科学指导。

In present project, we study the magnetic hardening mechanism of sintered Nd-Fe-B magnets processed with heavy rare earth (HRE) grain boundary diffusion (GBD). The microstructure, chemical composition, magnetic domain structure, and magnetic properties will be investigated for GBD processed sintered Nd-Fe-B magnets with controllable structure by using HRE hydride nanoparticles. A theoretical simulation model based on the GBD processed sintered Nd-Fe-B magnets will be set up by using the micromagnetic finite element/finite difference method. Moreover, effect of magnetization and demagnetization behavior on the magnetic properties of the magnets will be studied. Specially, the correlation between the macroscopic magnetization behavior and microscopic magnetic domain evolution of the magnets, as well as the magnetic hardening mechanism of the magnets during magnetic reversal process will be investigated. Finally, correlation between microstructure and magnetic properties of the GBD processed sintered Nd-Fe-B magnets with HRE will be set up. As a result, the technical magnetization theory of sintered Nd-Fe-B magnets can be enriched, and scientific instruction for fabricating novel low HRE content sintered Nd-Fe-B magnets for elevated temperature application with excellent magnetic properties will be proposed.