Effect of lattice distortion induced by Ce chemical valence on coercivity of Nd-Ce-Fe-B alloy

The (Nd1-xCex)(31.5)Fe67.5B1(x = 0, 0.15, 0.2, 0.25, 0.3, 0.5, 0.75 wt%) alloys were prepared by rapid solidifi- cation method. It is found that the coercivity, H-ci, abnormally increased to 1427.33 kA/m at x = 0.2. With the change of Ce content, the valence state of Ce shifted between 4 f(1) (+3) state and 4f (0) (+4) state. In the x = 0.2 ribbon, the Ce3+ has a high proportion, which is beneficial to the magnetic hardening of Ce2Fe14B type permanent magnetic materials. Meanwhile, the higher proportion of large radius Ce3+ and a lower proportion of small radius Ce4+ promoted the discrete change of the lattice parameters. The first principle calculations showed a large variation of lattice parameters with different Ce substitution occupying different positions. As a result, lattice distortions and scattered stress fields are formed inside the alloy. Such fields have high domain wall energy which hinder the movement of the domain walls during the process of reverse magnetization. (C) 2021 Published by Elsevier B.V.

Automated summary

The (Nd1-xCex)(31.5)Fe67.5B1 (x = 0, 0.15, 0.2, 0.25, 0.3, 0.5, 0.75 wt%) alloys were prepared by rapid solidification method. It was observed that the coercivity significantly increased to 1427.33 kA/m at x = 0.2, where Ce3+ proportion was high. The change in Ce valence state affects the magnetic properties, with Ce3+ promoting magnetic hardening in Ce2Fe14B type materials.