为优化热变形Nd-Fe-B磁体粗晶区的结构并提高其组织均匀性,本文以快淬磁粉和Cr粉为原料,采用热压及热变形工艺制备不同Cr含量Nd-Fe-B磁体,通过扫描电子显微镜、能谱仪、X射线衍射仪等研究Cr含量对磁体显微组织和磁性能的影响,并揭示其磁性能变化的机理。结果表明：适量添加Cr能显著提升Nd-Fe-B磁体的剩磁和最大磁能积。当w(Cr)为0.5%时,磁体的剩磁和磁能积分别可达1.39 T和353 kJ/m3。Cr在磁体中以单个颗粒的形式存在,富稀土相在Cr颗粒周围富集并形成包裹层。这种结构能有效改善Nd-Fe-B中富稀土相的不均匀分布,优化粗晶区的整体宽度和分布情况。磁体的织构因此得到优化,从而实现综合磁性能的提升。
To optimize the structure of the coarse-grained regions in hot-deformed Nd-Fe-B magnets and enhance their structural uniformity. In this paper, Nd-Fe-B magnets with different Cr contents were prepared using fast-quenched magnetic powder and Cr powder as raw materials through hot pressing and hot deformation processes. The effects of Cr content on the microstructure and magnetic properties of the magnets were studied by scanning electron microscope, energy spectrometer, X-ray diffractometer, and the mechanism of its magnetic property changes was revealed. The results indicate that an appropriate addition of Cr can significantly enhance the remanence and maximum magnetic energy product of Nd-Fe-B magnets. When w(Cr) is 0.5%, the remanence and magnetic energy product can reach 1.39 T and 353 kJ/m3, respectively. Cr exists as single particles, and the rare-earth-rich phase enriches around the Cr particles, forming a coating layer, which effectively reduces the inhomogeneous distribution of rare-earth-rich phases, optimizes the overall width and distribution of the coarse-grained regions. Thus, the texture of the magnet is optimized, leading to the improvement of comprehensive magnetic properties.
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