The effect of Nd content on the elemental interdiffusion mechanism of Nd–Dy–Fe–B magnets

In this work, the effect of Nd content on the interdiffusion mechanism of Nd/Dy elements in Nd-Dy-Fe-B magnets was elucidated by studying the differences in the magnetic properties, microstructure, and demagnetization process. As the Nd content increased, a uniform, continuous, and thicker layer of rare earth-rich (RE-rich) phase formed inside the magnets, which had a good magnetic isolation effect. During the demagnetization process, the strong ferromagnetic coupling effect between the main phase grains could be effectively weakened. At the same time, the thicker RE-rich phase layer could lead to a more obvious interdiffusion phenomenon of Nd/Dy elements, forming more (Nd, Dy)2Fe14B phases with high magnetocrystalline anisotropy fields, resulting in higher coercivity of the magnets. This paper elucidated the influence of Nd content on the interdiffusion mechanism of dual alloy Nd-Dy-Fe-B magnets, which had important significance for the preparation of high-performance Nd-Dy-Fe-B magnets.