相变调控高性能SmCo5基复相薄带磁体的微结构与磁机制的研究

In this project, it is proposed to optimize the alloy composition design by introducing decomposition-type Fe-based alloys which is thermodynamically stable into SmCo5 matrix with high anistropic field. And then, a new type of in-situ composite SmCo5-based ribbon magnets will be prepared by melt-spinning and heat treatment techniques. The aim of this work is to establish a novel SmCo5-matrixed multi-phase microstructure system, utilizing the phase transitions of Fe-based alloys and their interactions with the SmCo5 phase. Consequently, several magnetic mechanisms may arise in the magnets, and the cooperation of them can bring about the simutaneous improvement of coercivity and remanence. This project is about to study systematically the effects of multi-element addition, melt-spinning and heat treatment on the phase transitions in SmCo5-based ribbons, with an emphasis on the function of heat treatment with or without magnetic field. Microstructure and magnetic structure characteristics of the ribbons including the element distribution, the phase compositions and magnetic anisotropy as well as their evolution rules will be anyalyzed. On this basis, we can uncover the intrinsic correlations among the phase structure – microstructure – magnetic structure – magnetic mechanism, and set up the structure control and magnetic enhancement mechanism of SmCo5-based multi-phase ribbons. Through these researches, the problems of multi-element addition imbanlance and single magnetic mechanism existing in present SmCo5 alloys which impeded the improvement of magnetic properties are expected to be overcome. Furthermore, the theroretical system about the microstructure control and magnetic enhancement mechanism of permanent magnetic materials will be perfected. The research achievements can provide important theoretical basis and empirical experience for the development and application of SmCo5-type ribbon magnets.

本项目以高各向异性场的SmCo5合金为基体，引入热力学稳定的Fe基分解型合金进行成分优化设计，采用熔体快淬技术结合热处理工艺制备新型原位复合SmCo5基薄带磁体。项目旨在利用Fe基分解型合金的相变及其与SmCo5相的相互作用构建新的SmCo5基复相微结构体系，在磁体中引入多种磁性机制，并通过其协同作用实现剩磁和矫顽力的同时提高。项目将系统研究多元素添加、快淬及热处理对SmCo5基薄带中相变的影响；重点对比考察有或无磁场的热处理的作用，分析元素分布、物相种类、磁各向异性等微结构和磁结构特征及其演变规律；揭示相结构-微结构-磁结构-磁机制之间的内在关联，建立SmCo5基复相薄带的微结构控制及磁性增强机制。项目将克服SmCo5基合金中多元素添加时比例失调与磁硬化机制单一的问题，完善永磁材料微结构调控及磁性增强机制的理论体系，对于SmCo5型薄带磁体的开发和应用具有重要的理论意义和实用价值。

本项目以高各向异性场的SmCo5合金为基体，引入热力学稳定的Fe基分解型合金（Alnico、Fe-Cr-Co、Al-Cu-Fe合金）进行成分优化设计，采用熔体快淬技术结合热处理工艺制备了新型原位复合SmCo5基薄带磁体。项目首先对Alnico、Fe-Cr-Co、Sm(Co, M)5薄带合金进行了详细研究，然后研究了Sm(Co, M)5/Alnico、Sm(Co, M)5/Fe-Cr-Co、Sm(Co, M)5/Al-Cu-Fe合金，旨在利用Fe基分解型合金的相变及其与SmCo5相的相互作用构建新的SmCo5基复相微结构体系，在SmCo5形核机制的基础上引入钉扎机制，并通过其协同作用获得了更优异的综合磁性能。项目系统研究了多元素添加、快淬及热处理对SmCo5基薄带中相变的影响，重点对比考察了有或无磁场的热处理的作用，分析了元素分布、物相种类、磁各向异性等微结构和磁结构特征及其演变规律，揭示了相结构-微结构-磁结构-磁机制之间的内在关联，建立了SmCo5基复相薄带的微结构控制及磁性增强机制。.Alnico、Fe-Cr-Co的掺杂都促进了Sm(Co0.9Cu0.1)5薄带发生调幅分解，能同时提高Sm(Co0.9Cu0.1)5薄带的矫顽力和磁化强度，其中矫顽力分别提升至32.0 kOe及24.6 kOe。调幅分解后两种Sm(Co,M)5物相中的元素富集与Alnico及Fe-Cr-Co调幅分解后物相中的元素富集特征有很大相似性。这两种SmCo5基薄带的综合磁性能差异主要由所加合金元素的种类、元素分布、物相的相对含量及所形成的微结构等因素决定。相对于提升薄带矫顽力但降低磁化强度的无磁场退火，磁场热处理促进了SmCo5基复合型薄带中两相成分的均匀化，诱导掺杂元素分布在能够提高Sm(Co,M)5相磁各向异性的Co(2c)晶位，这导致掺杂了5wt%的Alnico或Fe-Cr-Co的SmCo5基薄带的磁化强度分别提高到70.6 emu/g与63.0 emu/g，并更为显著地将矫顽力分别提升至35.2 kOe和30.1 kOe。Al-Cu-Fe的复合也有类似效果。.项目克服了SmCo5基合金中多元素添加时比例失调与磁硬化机制单一的问题，完善了永磁材料微结构调控及磁性增强机制的理论体系，对于SmCo5型薄带磁体的开发和应用具有重要的理论意义和实用价值。