Effect of SiC Grain Size on Curing and Dielectric Properties of SiC/EP Composites

Abstract

This study investigates the preparation and properties of silicon carbide/epoxy (SiC/EP) composites, using epoxy resin as the matrix and micrometer-sized SiC particles as the inorganic filler. The influence of particle size on the curing behavior and dielectric properties of the composites is systematically analyzed. The scanning electron microscopy (SEM) confirms the absence of significant cross-sectional defects and shows that smaller particle sizes enhance the connectivity of SiC particles. Isothermal curing experiments indicate that a reduction in particle size improves the degree of cure in the composites. Conductivity measurements reveal that composites with smaller SiC particles exhibit lower conductivity and achieve a higher nonlinear coefficient, reaching a maximum of 6.31. Breakdown field tests demonstrate a nonlinear trend, with the breakdown field initially decreasing and subsequently increasing as particle size decreases. Similarly, dielectric spectrum analysis shows that the relative dielectric constant and dielectric loss first increase and then decrease with the reduction in SiC particle size.