Electrical Breakdown Characteristics of Epoxy/Hollow Silica Composite Materials

Abstract

Additives and fillers are traditionally added into an epoxy resin to improve the mechanical and thermal properties. Epoxy/hollow particle composites have been developed to produce composite materials with new functions such as a low dielectric constant, lightweight and high heat insulation. To understand the basic electrical properties of epoxy/hollow silica composites, breakdown voltage, capacitance, and partial discharge are measured. The breakdown strength of the epoxy/hollow silica composite and the breakdown strength of the epoxy/no hollow silica (normal silica) composite are almost the same regardless of the applied voltage waveform. The AC breakdown voltage at the 0-peak of the epoxy/hollow silica composite also agrees with the DC breakdown voltage. Furthermore, the sharing voltage of gas in hollow silica estimated by the partial discharge inception voltage and the electrical potential analysis exceed Paschen's voltage for the same distance. Breakdown is not determined by the continuous partial discharge in the hollow silica, suggesting that the interface between the silica particles and the epoxy resin may become the electrical weak point.