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Coercivity enhancement of hot-deformed NdFeB permanent magnets with AlCuZn eutectic alloy grain boundary diffusion

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Abstract

It is approved that grain boundary diffusion is an effective method to increase the coercivity of hot-deformed NdFeB magnet. In this paper, a new rare earth-free grain boundary diffusion source of hot-deformed magnet was studied. AlCuZn powders blended with commercial NdFeB powders were hot-compacted to obtain fully dense magnets, hot-deformed into anisotropic magnets and finally annealed to gain better homogeneity. Initially, the influences of annealing temperature and time on the magnetic properties of the specimens were studied and the optimal parameters of 600 °C and 60 min were achieved. Then, by changing the proportions of AlCuZn grain boundary diffusion, the coercivity, remanence and maximum energy product of the hot-deformed NdFeB magnets were examined. The result showed that with 1.0 wt% AlCuZn grain boundary diffusion and annealing at 600 °C for 60 min, the coercivity rose from 828 to 987 kA·m−1 without deteriorating the remanence. Microstructural analysis confirmed that AlCuZn diffused into the intergranular boundaries and the magnet diffused with AlCuZn possessed finer grains than that of without AlCuZn grain boundary diffusion.

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Acknowledgments

This study was financially supported by the National Key Research and Development Program (No. 2016YFB0700902).

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Authors and Affiliations

  1. National Engineering Research Center for Rare Earth Materials, General Research Institute for Nonferrous Metals, Beijing, 100088, China

    Ye-Qi Yu, Kuo-She Li, Hai-Jun Peng, Xin-Yuan Bai, Ning-Tao Quan, Kai-Wen Wu, Yang Luo & Dun-Bo Yu

  2. GRIREM Advanced Materials, Co. Ltd., Beijing, 100088, China

    Kuo-She Li, Hai-Jun Peng, Xin-Yuan Bai, Ning-Tao Quan, Kai-Wen Wu, Yang Luo & Dun-Bo Yu

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  1. Ye-Qi Yu
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Correspondence to Kuo-She Li.

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Yu, YQ., Li, KS., Peng, HJ. et al. Coercivity enhancement of hot-deformed NdFeB permanent magnets with AlCuZn eutectic alloy grain boundary diffusion. Rare Met. 41, 226–231 (2022). https://doi.org/10.1007/s12598-020-01531-0

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