Influence of Silica Filler Particle Size in Epoxy Resins on the Electrical Treeing Characteristic

Abstract

To understand the electric treeing properties, the time to breakdown is measured using a CCD camera. As the filler occupancy ratio increases, the average tree propagation speed in the sample with 80-μm silica filler particles decreases, whereas that of the sample with 48-μm silica filler particles increases. For the 80-μm filler sample, the increase in the effective length between electrodes and the field relaxation of the tree tip are predominant factors. However, the tree propagation effect at the interface between the filler and epoxy, which induces a faster tree propagation speed, is predominant for the 48-μm filler sample.