Development of high-coercivity SmFe12-based permanent magnet powders by reduction-diffusion method for achieving carbon neutrality

提出了一种在SmFe_（10）V_（2-x）Sm_2 O_3（x为Sm_2 O_3与SmFe_（10）V_2的摩尔比）体系中，通过在磁粉表面形成弱磁层来提高磁性的新方法。由于SmFe_（10）V_2 - 0.5Sm_2O_3磁性基体的相纯度和高性能得以保持，同时弱磁性的富Sm层抑制了相邻磁粉之间的交换作用，因此，具有这种特殊结构的SmFe_（10）V_2 - 0.5Sm_2O_3的最佳成分显示出744.9kA/m的高矫顽力。与传统的从磁性基体中析出弱磁性晶间相的方法不同，因此，我们的工作可能会提供一个新的见解，设计高矫顽力磁体。

We proposed a new approach to improve coercivity by generating weak-magnetic layers at the surfaces of fine magnetic powders in SmFe10V2-xSm2O3 (x represents the mole ratio of Sm2O3 to SmFe10V2) system. The optimal composition of SmFe10V2-0.5Sm2O3 with this special structure displays a high coercivity of 744.9 kA/m because the phase purity and high properties of magnetic SmFe10V2 matrix are maintained while the exchange interactions of adjacent magnetic powders are suppressed by the weak-magnetic Sm-rich layers.This work reports a new effective approach to acquire high coercivity by generating weak-magnetic layers around the fine magnetic powders, which is different from the conventional way to precipitate weak-magnetic intergranular phases from the magnetic matrixes. Thus, our work may give a new insight to design high-coercivity magnets.