AC breakdown characteristics of epoxy alumina nanocomposites

Experiments were conducted to measure the ac breakdown strength of 0.5 mm, thick epoxy alumina nanocomposites with different filler concentrations of 0.1, 1 and 5wt%. The experiments were performed as per the ASTM D 149 standard. It was observed that the ac breakdown strength was marginally lower up to 1wt% filler concentration and then increased at 5wt% filler concentration as compared to the unfilled epoxy. The Weibull shape parameter (β) increased with the addition of nanoparticles to epoxy. The dependence of thickness on the ac breakdown strength was also analyzed by conducting experiments on 1mm and 3mm thick unfilled epoxy and epoxy alumina nanocomposites of 1wt% and 5wt% filler concentrations. The DSC analysis was done to understand the material properties at the filler resin interface in order to study the effect of the filler concentration and thereby the influence of the interface on the ac breakdown strength of epoxy nanocomposites.