摘要：稀土Nd-Fe-B系永磁材料已经经历了三十多年的发展，目前国内外的研究热点集中于高矫顽力、低成本高性能材料研究两个方面。热压/热变形工艺制备过程具有简单，工艺流程短，近终成型，防止相分解等优点，有利于制备具有较高矫顽力和高的各向异性全密度永磁材料，然而目前制备的热变形钕铁硼磁体矫顽力远远低于理论预期。本文利用晶界扩散低熔点合金的办法，提高了具有富稀土相的商业-MQU-F-粉的矫顽力，并研究了低熔点合金晶界扩散对磁性能、微观结构的影响，同时，探究了在制粉阶段热处理对于液相分布的作用。
首先，本文探索热处理工艺对低熔点合金Pr-Cu晶界扩散磁粉矫顽力的影响。采用双合金法，将MQU-F与Pr82.4Cu17.59(wt.%)粉末按不同质量比混合均匀，将混合粉末进行一定时间的热处理，获得分布均匀的混合磁粉，并在适当的工艺条件下进行热压/热变形，获得致密的热变形磁体（密度~7.6g/cm3）。
其次，研究了热变形温度对添加低熔点合金磁体磁性能的影响，发现随热变形温度升高，矫顽力先升高后降低，热变形温度为810℃时矫顽力最高。因为热变形温度越高有助于低熔点合金的进一步扩散，但是热变形温度过高，晶粒发生异常长大，使矫顽力恶化。
最后，在本实验中，通过研究低熔点合金的Pr-Cu的添加量对磁体磁性能的影响。结果表明，添加10wt.%Pr-Cu，热变形磁体矫顽力从15.77kOe提高到了23.39kOe。磁体中液相富集区变多，晶界变厚。热处理可以有效的使Pr-Cu扩散均匀并且可以制得更高添加量的混粉磁体而不沾模具。
关键词 热压/热变形;MQU-F磁粉;Pr-Cu晶界扩散;矫顽力
Title Processing technology of hot-pressing and die upsetting NdFeB permanent magent materials
Abstract：The rare earth-series permanent magnetic materials have been developed for more than more than 30 years, at present, domestic and foreign research focuses on both high coercivity and low cost high-performance materials. The preparation process of hot-pressing/hot deformation process has the advantages of simplicity, short process flow and preventing phase decomposition, which is advantageous to the preparation of high coercivity and higher anisotropic full density permanent magnet materials, however, the coercivity of thermally deformed NdFeB magnets is far lower than theoretical expectation. In this paper, using the method of grain boundary diffusion low melting point alloy, the coercivity of commercial MQU-F powder with rich rare earth phase is improved, and the effect of grain boundary diffusion on the magnetic property and microstructure of low melting point alloy is studied, and the effect of heat treatment on liquid phase distribution in the milling stage is explored. Firstly, the effect of heat treatment technology on the process of grain Boundary diffusion in low melting point alloy Pr-Cu is investigated. The MQU-F and Pr82.4Cu17 (wt.%) were adopted by double alloy method. The powder is evenly mixed with different mass ratio, the mixed powder is heat-treated with a certain time, the mixed magnetic powder is distributed evenly, and hot-pressing/hot- deformation is obtained under the suitable technological conditions, and the compact hot-deformation magnet (density 7.6 g/cm3) is acquired.
Secondly, the effect of hot-deformation temperature on the magnetic properties of the added low melting point alloy magnets is studied, and the coercivity is found to be the highest when the thermal deformation temperature increases, and the coercivity rises first and then decreases after the thermal deformation temperature is 810℃. The higher the hot-deformation temperature is helpful to the further diffusion of the low melting point alloy, but the hot-deformation temperature is too high and the grains grow abnormally, which worsens the coercivity. 热压/热变形钕铁硼永磁材料制备技术:http://www.chuibin.com/wuli/lunwen_205409.html