新型复合永磁材料性能增强机理和稳定性研究

In accordance with the unique polyphase structure features of the new composite magnets, and previous experimental preparation and theoretic predictions on their magnetism and stability, by using a number of new preparation technologies, such as the double main phase (or multiple main phase) alloy, the original new composite permanent magnetic materials (including R-Fe-B/Nd-Fe-B, R-Fe-B/R-Co and polyphase composite magnets) will be prepared, and the research on the design, the basic theory of controllable preparation and performance enhancements mechanism of "multi-phase, multi-scale” new composite magnets will be carried out. The magnetic interactions and the formation mechanism of magnetic hardening between the grains with different anisotropy constant in anisotropic composite system will be clarified. The influence mechanism of composition and microstructure on dynamic magnetization and the magnetization reversal mechanism and their temperature dependent properties will be investigated. The association mechanism of the microstructure of composite magnets on their magnetic properties, conductive performance and stability will be revealed. The magnetic coupling mechanism, and the performance enhancement mechanism of the new composite permanent magnetic materials will be analyzed by using various calculation methods, and the material intrinsic magnetic criterion and theoretical model will be constructed. The experimental and theoretical studies on the magnetic structural stability of the new composite permanent magnet materials with high-quality use of rare earth elements will be developed. We are striving to achieve breakthroughs in basic scientific research of the recycling new composite permanent magnet materials.

针对新型复合永磁材料独特的多相结构特征，以及前期关于其磁性和稳定性的实验准备和理论预测，通过采用双主相（或多主相）合金等多相复合材料制备新技术，制备具有原创性的新型复合永磁材料（包括R-Fe-B/Nd-Fe-B、R-Fe-B/R-Co及多相复合磁体），开展“多相、多尺度”新型复合稀土永磁材料的设计、可控制备基础理论和性能增强机理研究。澄清各向异性复合体系中不同各向异性常数的磁性晶粒间的磁相互作用与磁硬化的形成机制；研究成分和微结构对其动态磁化、反磁化的影响机制及其温度依赖特性；揭示复合磁体微观结构与其磁性、导电性和稳定性等之间的关联机制；利用多种计算方法求解新型复合永磁材料磁性耦合和性能增强机理，构建材料内禀磁性判据及相关理论模型。开展优质利用稀土元素的新型复合永磁材料磁结构稳定性的实验和理论研究。力争在可循环利用的新型复合永磁材料基础科学研究方面取得突破。

针对新型复合永磁材料独特的多相结构特征，采用双主相（或多主相）合金等多相复合材料制备新技术，制备具有原创性的新型复合永磁材料（包括包括R-Fe-B/Nd-Fe-B、R-Fe-B/R-Co及多相复合磁体等双相或多相复合磁体），开展“多相、多尺度”新型复合稀土永磁材料的设计、可控制备基础理论和性能增强机理研究。采用熔体快淬、高能球磨、热压/热变形、磁控溅射等技术手段制备出了NdFeB/CeFeB、NdFeB/PrCo5、NdFeB/SmCo5、PrFeB/PrCo5、MnBi/Co、Mn-Bi/Fe65Co35、 Nd2Fe14B/Fe65Co35 /Nd2Fe14B、(Nd,Ce)-Fe-B等新型复合永磁材料，取得了较好的进展。制备出了高性能的大块NdFeB纳米晶复合磁体，经中国计量科学研究院磁性测量实验室测量，最大磁能积达到了53.9MGOe。制备的NdFeB/SmCo5、PrFeB/PrCo5型复合磁体的矫顽力温度系数优于单相的磁体，磁能积介于两个单相磁体之间；采用热压工艺制备了大块Nd-Fe-B/PrCo5复合磁体，热压过程没有造成相的分解以及元素的扩散，少量添加PrCo5，剩磁略有降低，矫顽力基本不变，少量添加PrCo5可改善磁体的矫顽力温度系数。采用微磁学计算的MnBi/Co和MnBi/Fe65Co35与单相MnBi磁体的理论磁能积相比，MnBi/Co和 MnBi/Fe65Co35复合磁体的最优理论磁能积分别提高了239%和88%。通过微磁学计算Nd2Fe14B/Fe65Co35/Nd2Fe14B多层膜，其最大磁能积高达630kJ/m3 (78.8MGOe)。.多个体系的复合磁体研究表明，双相或多相复合磁体能够充分发挥各相的优势，获得磁性能和微结构不同于现有稀土永磁体的复合磁体，通过对这些复合磁体的微观结构和磁硬化机理研究，能够更好的理解硬磁相/硬磁相之间的磁相互作用机理和矫顽力机制，对硬磁相/软磁相型的双相纳米晶复合磁体的研究可以起到借鉴和推动意义。同时，这些复合磁体的研制成功，能够更好的完善永磁体体系，拓宽永磁体的使用范围。