Enhancing the Tb utilization efficiency and coercivity in high Ce content Nd-Fe-B magnets by Pr-Tb-Zn grain boundary diffusion

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials Pub Date : 2025-06-23 DOI:10.1016/j.jmmm.2025.173316

Zhibin Li , Wenbing Fan , Rongshun Lai, Haibo Xu, Xiaoxuan Zheng, Xin Wang, Qianji Wang, Bo Jiang, Xianglong Zhou, Qiang Ma

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引用次数: 0

Abstract

Grain boundary diffusion is an effective method for improving the coercivity of Nd-Fe-B sintered magnets. However, the coercivity is not significantly enhanced after grain boundary diffusion in magnets with high Ce content due to the presence of the REFe₂ phase. In this study, we have designed a novel low-melting-point ternary diffusion source of Pr₅₃Tb₄₂Zn₅ that can effectively improve the diffusion efficiency and utilization of Tb, thereby significantly enhancing the coercivity of the magnets. After diffusion of Tb and Pr₅₃Tb₄₂Zn₅ in sintered magnets with 25.8 wt% Ce substituted, the coercivity of the magnets was enhanced from 1019.7 kA/m to 1412.9 and 1500.5 kA/m, respectively. Observations of the microstructure and element distribution showed that after diffusion of Tb and Pr₅₃Tb₄₂Zn₅, Tb penetrated the surface of the RE₂Fe₁₄B main phase grains and formed a Tb-rich shell, which significantly increased its anisotropy field. Compared to the Tb diffused magnets, the Pr₅₃Tb₄₂Zn₅ diffused magnets exhibited a more uniform distribution of the Tb-rich shell and a deeper diffusion depth. Additionally, transmission electron microscopy analysis indicated that in the Tb diffused magnets, some Tb elements were consumed by the REFe₂ phase, whereas in the Pr₅₃Tb₄₂Zn₅ diffused magnets, there was almost no Tb in the REFe₂ phase, which improved the utilization of Tb and resulted in a higher increment in coercivity.

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利用Pr-Tb-Zn晶界扩散提高高Ce Nd-Fe-B磁体的Tb利用效率和矫顽力

晶界扩散是提高钕铁硼烧结磁体矫顽力的有效方法。而在高Ce含量磁体中，由于REFe2相的存在，晶界扩散后矫顽力没有明显增强。本研究设计了一种新型的低熔点三元扩散源Pr53Tb42Zn5，可以有效提高Tb的扩散效率和利用率，从而显著提高磁体的矫顽力。在Ce含量为25.8 wt%的烧结磁体中扩散Tb和Pr53Tb42Zn5后，磁体的矫顽力分别从1019.7 kA/m提高到1412.9和1500.5 kA/m。显微组织和元素分布观察表明，Tb和Pr53Tb42Zn5扩散后，Tb穿透RE2Fe14B主相晶粒表面，形成富Tb壳层，各向异性场显著增大。与Tb扩散磁体相比，Pr53Tb42Zn5扩散磁体富Tb外壳分布更均匀，扩散深度更深。此外，透射电镜分析表明，在Tb扩散磁体中，部分Tb元素被REFe2相消耗，而在Pr53Tb42Zn5扩散磁体中，REFe2相中几乎没有Tb元素，这提高了Tb的利用率，导致了更高的矫顽力增量。

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来源期刊

Journal of Magnetism and Magnetic Materials 物理-材料科学：综合

CiteScore

5.30

自引率

11.10%

发文量

1149

审稿时长

59 days

期刊介绍： The Journal of Magnetism and Magnetic Materials provides an important forum for the disclosure and discussion of original contributions covering the whole spectrum of topics, from basic magnetism to the technology and applications of magnetic materials. The journal encourages greater interaction between the basic and applied sub-disciplines of magnetism with comprehensive review articles, in addition to full-length contributions. In addition, other categories of contributions are welcome, including Critical Focused issues, Current Perspectives and Outreach to the General Public. Main Categories: Full-length articles: Technically original research documents that report results of value to the communities that comprise the journal audience. The link between chemical, structural and microstructural properties on the one hand and magnetic properties on the other hand are encouraged. In addition to general topics covering all areas of magnetism and magnetic materials, the full-length articles also include three sub-sections, focusing on Nanomagnetism, Spintronics and Applications. The sub-section on Nanomagnetism contains articles on magnetic nanoparticles, nanowires, thin films, 2D materials and other nanoscale magnetic materials and their applications. The sub-section on Spintronics contains articles on magnetoresistance, magnetoimpedance, magneto-optical phenomena, Micro-Electro-Mechanical Systems (MEMS), and other topics related to spin current control and magneto-transport phenomena. The sub-section on Applications display papers that focus on applications of magnetic materials. The applications need to show a connection to magnetism. Review articles: Review articles organize, clarify, and summarize existing major works in the areas covered by the Journal and provide comprehensive citations to the full spectrum of relevant literature.