Preparation and magnetic properties of core-shell structured Fe-Si/Fe_3O_4 composites via in-situ reaction method

摘要

The Fe-Si/Fe_3O_4 soft magnetic composites (SMCs) have been fabricated via in-situ reaction method. A layer of Fe_3O_4 was formed on the Fe-Si particles in the KNO_3 solution, and the growth mechanism of the Fe_3O_4 coating layer has been studied, and its formation and thickness can be controlled by adjusting the concentration of KNO_3 solution to obtain the microstructure of the composites and then adjust the magnetic performance of SMCs. The formation of Fe_3O_4 shell on Fe-Si particles can effectively reduce the core loss of the composites. The samples in-situ reacted in 0.1 mol/L KNO_3 solution exhibit excellent comprehensive properties with high saturation magnetization, relatively high permeability (34), great frequency stability of permeability, and very low core loss of 13.6 w/kg (measured at 20 mT and 150 kHz).