Enhanced thermal and dielectric performance of epoxy resin/aluminum nitride nanocomposites at high temperatures

The effects of nano-aluminum nitride (nano-AlN) on the thermal conductivity and dielectric performances of epoxy resin (EP) are investigated. The addition of nanoparticles in the materials is characterized. The trap characteristics of the samples are estimated using the surface potential decay (SPD) measurements at high temperatures. The results show that the nano-AlN fillers are well dispersed in the nano-AlN composites. The thermal conductivity consistently increases with an increase of the nano-AlN content. The DC breakdown strength of the EP is enhanced with the addition of the nanoparticles as well, especially for the 0.5 and 1 wt% EP/AlN composites. The DC conductivity of the EP/AlN composites increases more obviously at the high temperature. The initial surface charge density of the samples with the same content of nano-filler decreases with the increase of the temperature. Both the addition of nanoparticles and high temperature can improve the apparent carrier mobility of the EP sample. The trap density and trap level of the deep traps decreases with the increase of the temperature. It is postulated that shallow traps influence the voltage decay in the EP samples and increase the activation energy and the apparent carrier mobility of the specimens at the high temperature.