Tracking of epoxy/MgO nanocomposites under DC Stress

Epoxy/MgO nanocomposites were obtained by mixing nano-MgO particles into neat epoxy with filler loading of 1, 3, 5, 7 wt%. To study the effects of nano-particle content on the tracking failure under dc stress, tracking experiments were carried out. The dc resistance to tracking failure, tracking process and discharge current were measured in relation with the content and the applied voltage. The results show that when the filler content increases from 0 to 5 wt%, the number of drops to tracking failure rises and the erosion depth declines. But the reverse varying tendency happens when the content continue to increase from 5 to 7 wt%. With the purpose of reflecting the underlying mechanism in the tracking failure affected by the nano particles, the recurrent plot technique was applied to reveal the nonlinear characteristics of discharge currents. Finally, the experimental results suggest that the tracking resistance of epoxy can be improved by nano-MgO particles. The best results were obtained with the filler content of 5 wt%.