纳米双相复合磁粉的原位制备及其热压/热变形研究

项目名称： 纳米双相复合磁粉的原位制备及其热压/热变形研究

项目编号： No.21201041

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 无机化学

项目作者： 张珂

作者单位： 钢铁研究总院

项目金额： 25万元

中文摘要： 目前实际得到的纳米双相复合磁体的磁能积，与理论预测相比仍有较大的差距，软硬磁相纳米尺度的均匀分散以及各向异性结构的构筑制约着其发展。本项目将"自下而上"的纳米制备手段与传统冶金的热压/热变形工艺相结合，以NdFeB快淬粉作为形核中心，借鉴"种子调控"的方法在其表面原位制备均匀包覆的软磁性Fe纳米颗粒。有利于实现对软磁性Fe纳米颗粒的尺寸、分散状态、包覆厚度的控制，从而对软硬磁相的组成及磁交换耦合作用进行调控。进一步利用热压/热变形工艺的高压剪切流变技术，实现硬磁相易磁化c轴的高取向度，形成具有取向织构的磁体，制备出各向异性的纳米双相复合磁体。通过构建理论模型分析软硬磁相的交换作用畴结构以及界面效应，阐明纳米双相复合磁体的矫顽力机制以及磁交换耦合机制，建立易于实现各向异性复合体系内纳米耦合的微观结构和条件。

中文关键词： 自下而上；纳米双相；热变形；永磁材料；

英文摘要： The practical obtained energy product of nano-composite magnets is far below the prediction. The uniform dispersion of soft and hard phase in nanoscale as well as the anisotropy structure are two key factors that constrain the development. In this research plan we combine the "bottom-up" synthesis method for nanomaterials with Hot Press/Hot Deformation (HP/HD) process of traditional metallurgy. The soft phase of Fe nanoparticles are in situ uniformly precipitated on the surface of NdFeB rapid quenching powders via the "seed-mediated" approach. By this way the size, dispersion and coating thickness of Fe nanoparticles can be finely controlled which is in favor of tuning the compositions between soft and hard phase and the magnetic exchange coupling. The as-prepared nano-composite powders are followed by undergoing high pressure shear rheology of HP/HD process after which the high oriented c-axis can be achieved and textured magnet can be formed. After the two steps we could get anistropic nano-composite magnets. By constructing a theoretical model we could further analyze the domain structure and interfacial effect of the exchange coupling of soft and hard magnetic phase, clarify the coercivity and magnetic exchange coupling mechanism. The optical microstructures and exchange coupling conditions for anisotropic n

英文关键词： bottom-up；nanocomposite；hot deformation；permanet magnet；