Microstructure Optimization and Magnetic Properties Enhancement of Hot Pressed Nd-Fe-B Magnets via Grain Boundary Diffusion of NdCu Powder
Microstructure Optimization and Magnetic Properties Enhancement of Hot Pressed Nd-Fe-B Magnets via Grain Boundary Diffusion of NdCu Powder
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DOI：
10.1016/j.jmmm.2022.170325
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发表时间：
2022-12
影响因子：
2.7
通讯作者：
Wei Li;Q. Feng;Cheng Chen;Xiaosong Zhang;Zhenglin Fu;Yuhua Hou;Youlin Huang
中科院分区：
文献类型：
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作者：
Wei Li;Q. Feng;Cheng Chen;Xiaosong Zhang;Zhenglin Fu;Yuhua Hou;Youlin Huang
Nd-Fe-B磁体的显微组织改性是调节磁体磁性能的关键。本文通过添加低熔点NdCu合金来提高NdFeB薄带的矫顽力，并采用热压烧结法制备了高矫顽力纳米晶NdFeB磁体。结果表明，Nd-Cu粉掺量为15wt%时，NdFeB粉的矫顽力提高最大，达到12.69kOe。经HPS处理后，获得了磁性能优良的致密磁体。显微组织分析表明，Nd-Cu合金在热处理过程中沿沿着向硬磁晶粒内部扩散。Nd、Pr和Cu在晶界相中的富集削弱了晶界相的磁性，降低了晶间交换耦合。这是磁致伸缩性增强的主要原因。此外，Nd 70 Cu 30的扩散可以显著提高磁体的热稳定性。
Microstructure modification of Nd-Fe-B magnets plays a key role in regulating magnetic properties. In this work, low melting point NdCu alloy was added to improve the coercivity of NdFeB ribbons, and then high coercivity nanocrystalline NdFeB magnets were prepared by hot pressing sintering (HPS). The result shows that the coercivity of NdFeB powders blending with 15 wt% Nd-Cu powders obtained a maximum increment, as high as 12.69 kOe. After HPS, the fully dense magnets with excellent magnetic properties are obtained. Microstructure analysis confirmed that the Nd-Cu alloy has diffused into the interior of hard magnetic grains along the grain boundary during heat treatment. The enrichment of Nd, Pr, and Cu in the grain boundary phase weakens the magnetism of the grain boundary phase and reduces the intergranular exchange coupling. This is the main reason for the coercivity enhancement. In addition, the diffusion of Nd70Cu30can significantly improve the thermal stability of the magnets.