Effect ofSiO2particle size scale on the electrical performance of epoxy‐based nonlinear conductive composite

Abstract

AbstractIn this paper, SiO2particles with three particle sizes of 60 nm, 2 μm, and 25 μm were added as fillers into the composites prepared by epoxy resin and micron silicon carbide to investigate the mechanism of SiO2particle size on the nonlinear electrical conductivity and breakdown characteristics of the composites. Compared with SiC/EP composites, the smaller the added SiO2particle size, the lower the current density at high fields and the higher the breakdown field strength of SiO2/SiC/EP composites. The nonlinear coefficients of SiO2/SiC/EP composites increased slightly with the addition of 1phr 25 μm SiO2and 4phr 2 μm SiO2, and the breakdown field strengths were increased by 55.36% and 66.77%, respectively. The SiO2/SiC/EP composites with the addition of 4phr 60 nm SiO2particles showed the most significant attenuation of the conductivity current and the most prominent enhancement of the breakdown field strength, but the nonlinear coefficient was reduced by 24.6%. With the increase of SiO2doping amount, compared with the composites with the same particle size and low doping amount, the larger the SiO2particle size, the decrease of the current density of the composites under high field intensity is more obvious, and the dielectric constant drops even more.