Optimizing the high-frequency magnetic properties of soft magnetic composites via surface nanoengineering

Owing to the presence of large residual internal stress during cold compaction, it is difficult to optimize the multiple high-frequency magnetic properties of amorphous soft magnetic composites (ASMCs) simultaneously. Here, a surface nanoengineering strategy was proposed to address the above dilemma by constructing a stress buffer layer composed of amorphous nano-particles, between amorphous powder and insulation coating. The amorphous FeSiBCCr@x wt.% FeB (x = 0.5, 1, 3) composite powders with core-shell structures were successfully prepared via an in-situ chemical reduction method. Especially, when the composite ratio of nano-particles is 1 wt.%, the comprehensive properties of the ASMC reach the best balance. Compared with the FeSiBCCr ASMC, the saturation magnetization of the modified ASMC enhances from 153 emu/g to 171 emu/g. Meanwhile, the core loss decreases by 28.25%, while the effective permeability increases by 25% and can stabilize to ∼20 MHz. Therefore, our work provides a strategy for achieving superior comprehensive soft magnetic properties of ASMCs via surface nanoengineering, which presents enormous application potential in high-frequency electric devices.