Extraction of aging markers for nanostructured epoxy resin aged under surface discharges

In this paper the effect of partial discharge induced degradation on epoxy-resin specimens filled by silica nanoparticles is discussed. In particular, the experimental results show that nanostructured materials exhibit longer failure times with respect to base epoxy resin and increasing nanofiller concentration the resistance to partial discharge activity improves significantly. Degradation evolution is investigated through continuous monitoring of partial discharges and periodic physical surface profile measurements. It is shown that the former provides useful quantities, e.g. inception phase, to be associated with the extent of specimen surface erosion. This allows PD endurance of nanostructured materials to be evaluated by means of on-line measurements which can provide further information also on PD erosion phenomenology (e.g., surface erosion or pit formation/growth).