新型自组装双主相钴基高温磁体的多维显微结构演变及磁性关联

This project is guided by the urgent need of the magnets capable of operating at above 550 °C for the national major strategic projects. By starting from the action mechanism of the compositions of the magnets, and combining the Micromagnetic simulations, First-principles calculations based on PP-PAW and FP-LAPW methods, Molecular dynamics and Finite element analysis, the multi-scale microstructures of Co-base high temperature magnets during the self-assembled processes will be investigated via the multiple experimental characterization methods. The comprehensive researches will be done to explore the evolution of magnetic properties as a function of the spatial scales of the cell and cell wall, as well as temperature-, time- and magnetic-field-dependent properties. In order to obtain the correlations between the heat treatment processes and the microstructural and magnetic properties of the magnets, the dynamic magnetization reversal mechanism of high-temperature Co-based permanent magnets under magnetic field, temperature field, time and other complex electromagnetic environment will also be further studied. The theoretical and experimental basis for optimizing and improving the high temperature service characteristics of existing Samarium Cobalt permanent magnets and the development of a new generation magnetic material with higher operating temperature will be established.

本项目以国家重大战略工程急需服役温度在550℃以上的耐高温高性能永磁材料为研究导向，从合金成分在磁体中的作用机制出发，利用微磁模拟、基于PP-PAW和FP-LAPW方法的第一性原理计算、分子动力学与有限元分析结合，通过不同的实验表征手段，研究钴基高温合金自组装过程的多尺度显微结构，探索磁性能随晶胞和胞壁空间尺度、随磁场、温度场以及时间等多维度下的演变规律，针对高温钴基永磁材料在磁场、温度场、时间场以及复杂电磁环境中的动态磁化翻转机制，进而获得热处理工艺与显微结构以及磁体磁性能的关联。为优化和提高现有钐钴永磁材料的高温服役特性，开发新一代更高使用温度永磁材料奠定坚实的理论和实验基础。

本项目不同常规的液相烧结，双合金和软硬磁纳米双相等技术方法，通过采用多相复合材料制备新技术，主要针对新型双硬磁或多多硬磁主相复合永磁材料独特的结构特征，开展“多硬磁相、多尺度”新型复合稀土永磁材料（包括R-Fe-B/Nd-Fe-B、R-Fe-B/Sm-Co及多相复合磁体）的设计、可控制备基础理论和矫顽力机制的探讨。探索制备兼具多种单相永磁优点的新型复合型永磁材料，深入研究复合磁体中相分布形态以及不同相间的界面状态；研究材料成分、结构与其磁性能之间的构效关系。研究磁体内部不同磁性相之间的交换作用，静磁作用以及磁体磁硬化的详细机制；尝试利用微磁学理论、第一性原理计算，并结合蒙托卡罗方法，求解新型复合永磁材料磁性耦合，探索“1+1>2”的最佳复合结构。为新型高性能永磁材料的研发，平衡稀土资源在稀土永磁中的应用奠定理论基础。本项目中的双主相是指双硬磁主相。