Enhancing Coercivity and Thermal Stability in High-Remanence Nd-Fe-B Magnets via TbF3 Grain Boundary Diffusion

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia Pub Date : 2025-06-05 DOI:10.1016/j.actamat.2025.121176

Shilin Li, Youhong Peng, Yaodong Wu, Yuqing Xing, Yu Zhang, Tao Liu, Sitian Cai, Qiong Wu, Ming Yue, Haifeng Du, Jin Tang

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Abstract

Applications in the field of magnetic motors, separators, etc., necessitate permanent magnets exhibiting a synergy between coercivity and remanence. However, sintered Nd-Fe-B magnets with high remanence feature relatively large grains leading to a decrease in coercivity. In this study, we investigate the impact of the TbF₃ grain boundary diffusion process (GBDP) on sintered Nd-Fe-B magnets possessing a high remanence of 14.92 kGs but a low coercivity of 9.92 kOe. Through TbF₃ diffusion, we observe a substantial increase in room-temperature coercivity by 84%, reaching 18.25 kOe, accompanied by a relatively minor reduction in remanence (∼ 0.31 kGs). Notably, the diffused magnets maintain a coercivity of 5.3 kOe at elevated temperatures (150°C), demonstrating effective improvement in thermal stability. The modifications in core-shell structures and grain boundaries due to the GBDP are systematically characterized using an electron probe micro-analyzer and transmission electron microscopy. Furthermore, micromagnetic simulations are employed to discuss the enhancement in coercivity attributed to shell thickness. Our findings, which achieve a synergy between coercivity and remanence in Nd-Fe-B sintered magnets, hold the potential to advance applications of permanent magnets.

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利用TbF3晶界扩散增强高剩磁Nd-Fe-B磁体的矫顽力和热稳定性

在磁性电机、磁分离器等领域的应用，需要永磁体在矫顽力和剩磁之间表现出协同作用。然而，高剩余率烧结钕铁硼磁体晶粒较大，导致矫顽力降低。在本研究中，我们研究了TbF3晶界扩散过程（GBDP）对烧结Nd-Fe-B磁体的影响，该磁体具有14.92 kGs的高剩余力和9.92 kOe的低矫顽力。通过TbF3扩散，我们观察到室温矫顽力大幅增加84%，达到18.25 kOe，同时剩余物减少相对较小（约0.31 kGs）。值得注意的是，扩散磁体在高温（150°C）下保持5.3 kOe的矫顽力，表明热稳定性得到有效改善。利用电子探针微分析仪和透射电子显微镜系统地表征了GBDP对核壳结构和晶界的影响。此外，采用微磁模拟方法讨论了壳体厚度对矫顽力的影响。我们的研究结果在Nd-Fe-B烧结磁体中实现了矫顽力和剩余力之间的协同作用，具有推进永磁体应用的潜力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Acta Materialia 工程技术-材料科学：综合

CiteScore

16.10

自引率

8.50%

发文量

801

审稿时长

53 days

期刊介绍： Acta Materialia serves as a platform for publishing full-length, original papers and commissioned overviews that contribute to a profound understanding of the correlation between the processing, structure, and properties of inorganic materials. The journal seeks papers with high impact potential or those that significantly propel the field forward. The scope includes the atomic and molecular arrangements, chemical and electronic structures, and microstructure of materials, focusing on their mechanical or functional behavior across all length scales, including nanostructures.