Tracking resistance of epoxy/Al2O3 nanocomposites under DC voltage

Based on the viewpoint that the properties of polymer could be changed by nano particles, epoxy/Al₂O₃ nanocomposites were prepared to study the effects of nano particles on tracking failure. Nano-Al₂O₃ particles were mixed into neat epoxy with filler content of 1, 3, 5 and 7 wt%. Tracking experiments were carried out by applying positive dc voltage. The effects of the filler content on tracking resistance were studied by recording the tracking phenomena and discharge currents during the tracking process. Obtained results showed that when the filler content increased from 0 to 5 wt%, the duration of the whole tracking process increased, the weight loss of nanocomposites and the area of tracking pattern decreased. The opposite tendency was observed when the content increased from 5 to 7 wt%. The discharge currents were studied using the recurrence plot technique to investigate the nonlinear characteristics of discharge currents and reflect the effects of nano particles on discharge. The fractal dimension method was used to study the structures of scintillation discharge distribution and tracking pattern to analyze the effects of nano particles on the occurrence of tracking pattern. The results showed that the nano-Al₂O₃ particles had very significant effects on the tracking resistance of epoxy. The best restriction effects were obtained with the filler content of 5 wt%.