Differences in the magnetic properties of Finemet/FeSi soft magnetic composites prepared with epoxy resin/nano-oxide composite coating layers

Organic and inorganic composite coating layers have attracted significant attention because of their excellent insulating properties. In this study, nano-oxide/epoxy resin composite coating layers were prepared in FeSiBCuNb/FeSi soft magnetic composites (SMCs). And the influence of Al 2 O 3 , CeO 2 , SiO 2 and Fe 3 O 4 nano-oxides on the properties of SMCs is analyzed in detail. The density and phase structure of nano-oxides result in differences in their modifiable and agglomerative properties, affecting the insulation coating layers on the surface of magnetic particles. This is refilected as a change in magnetic properties on a macroscopic scale. Analysis results show that the introduction of nano-Al 2 O 3 significantly decreases the effective permeability of SMCs. However, it exhibits excellent loss characteristics in the high-frequency field of 5 MHz. The introduction of nano-CeO 2 optimizes the losses and effective permeability of SMCs at 1 MHz. And the losses and effective permeability of SMCs are 591.4 mW/cm 3 (20mT, 1 MHz) and 35.5 (1 MHz), respectively. This work provides a reference for selecting nano-oxides in the insulation coating layers of SMCs.