无稀土MnBi基永磁薄膜的合成及其沉积动力学

With the rare earth resources dwindling and its price increasing rapidly, the development of a new kind of rare earth free permanent magnet with high magnetic properties is not only the requirement for the magnetic industry, but also the major issue for the sustainable development of Chinese rare earth industry. In this project, based on the comprehensive knowledge of electrodeposition nucleation theory，crystal growth dynamics, and micro-magnetic, a new kind of rare earth free MnBi-based multicomponent alloy permanent magnetic thin film with strong texture and high performance is prepared by the method of electrodeposition and laser surface modification technology. The effect of external conditions such as temperature, laser power and calcination atmosphere in laser surface modification technology , on nanocrysalline oriented growth dynamics and the evolution of the micro-magnetic domain structure behavior were researched in rare earth free MnBi-based alloy multicomponent alloy permanent magnetic thin film. Also the reason was clarified that the microstructure in permanent magnetic thin film including the grain oriented growth, evolution of defect, the grain boundary state and its particle accumulation mode, determines the magnetic exchange coupling effect. The physical mechanism of the domain wall moving and domain structure evolution was investigated. The core issue was to clarify the mechanism of the outfield inducing strong texture formation in rare earth free MnBi-based multicomponent alloy permanent magnetic thin film. We will reveal the internal impact about the effect strong texture on the exchange coupling between the magnetic moment changes and nanocrystals intrinsic spin/orbit coupling. The above results will contribute to the theoretical research for developing a new high-magnetic rare earth free permanent magnetic thin film and its microstructure design.

随着稀土资源日益减少、价格迅猛增长，及时开发一类新型高磁性无稀土永磁体不但是磁性行业发展的要求，更是我国稀土产业可持续发展的重大课题之一。本申请基于电沉积成核理论、晶体取向生长动力学及微磁学的基础上，综合利用电沉积技术和激光表面改性技术，制备出一类新型强织构、高性能的无稀土MnBi基多元合金永磁薄膜；通过研究激光表面改性技术中的温度、激光功率及煅烧气氛等条件作用下无稀土MnBi基多元合金永磁薄膜的纳米晶取向生长动力学和微磁畴结构的演化行为，揭示永磁薄膜中的晶粒取向生长、缺陷形成、晶界状态及其颗粒堆积方式等微结构对磁交换耦合效应、畴壁移动和磁畴结构演化的影响规律及其控制机理；核心问题是阐明外场诱导MnBi基多元合金永磁薄膜纳米晶织构的形成机理，并从理论上阐明强织构与交换耦合、磁矩改变及纳米晶粒之间自旋/轨道耦合的内在关联，为开发新型高磁性无稀土永磁薄膜的微结构设计及其可控技术提供理论。

无稀土MnBi基多元合金永磁薄膜材料由于其优异的磁性能及价格低廉，有望取代价格高昂的稀土永磁材料，具有非常美好的应用前景。本项目在电沉积成核理论、晶体取向生长动力学及微磁学的基础上，综合利用电沉积技术和激光表面改性技术，制备了新型高性能的无稀土MnBi基多元合金永磁薄膜和新型的锂离子电池磷基合金负极材料。通过研究激光表面改性技术中温度、处理时间等对无稀土MnBi基多元合金永磁薄膜的纳米晶取向生长动力学和微磁畴结构的演化行为，揭示了永磁薄膜中的晶粒取向生长、晶界状态和磁畴结构演化的影响规律及其控制机理；阐明了MnBi基多元合金永磁薄膜纳米晶织构的形成机理，为开发新型高磁性无稀土永磁薄膜的微结构设计及其可控技术提供理论；系统研究了新型磷基合金负极材料的制备方法和电化学性能，揭示了制备工艺-性能之间的内在联系，这些研究有利于深化对磷基合金负极材料的认识，同时对进一步拓展其在锂离子电池中的应用也具有重要的理论指导意义和应用价值。