SiC/SiO2 filler reinforced EP composite with excellent nonlinear conductivity and high breakdown strength

In this paper, silicon carbide/silicon dioxide (SiC/SiO₂) filler with core/shell structure, as a filler in epoxy resin (EP), is studied. The effect of the thickness of the SiO₂ shell is studied as it affects the microstructure and electrical properties of the SiC/SiO₂/EP composites at various temperatures. Compared with SiC/EP composites, the SiC/SiO₂/EP composites show outstanding electrical properties. The nonlinear coefficient of the 4 nm-SiC/SiO₂/EP composites increases from 2.88 (5 wt% SiC/EP) to 3.79, and the breakdown field strength increases 1.23 times. With increasing temperature, the electrical conductivity increases and the threshold field strength decreases. Moreover, as the SiO₂ shell thickness increases, the breakdown field strength of the composite increases, and shows a weaker temperature dependence.