Space charge measurements on different epoxy resin-alumina nanocomposites

Recently a number of papers have reported enhanced electrical (ageing and breakdown) performance of nano-composites when compared to the properties of the base resin material. The physical reasons for this improvement are the subject of many current studies and have yet to be fully formulated. In this work, the build-up and decay of space charge in epoxy resin materials, containing nano-particles of alumina of various concentrations, 0.5% to 2% was investigated during the application of DC voltage and after voltage removal. Space charge profiles in thin film samples were investigated using the Pulsed Electro-Acoustic (PEA) technique. The results were compared with the space charge behavior of the unfilled resin and for the 1% nano-filled resin with differing levels of absorbed moisture. The results demonstrate that the space charge behavior is dominated by the properties of the host resin. However, the accumulation of positive charge at the anode is affected by the concentration of filler particles. The results also demonstrate the importance of controlling the amount of absorbed moisture in the samples as this governs the dynamics of the charge build-up and decay in the samples.