Investigation of Charge Dynamics in the Corona‐aged Silicone Rubber Alumina Nanocomposite

The effect of corona aging on the surface potential dynamics and charge trap characteristics of silicone rubber alumina nanocomposite are examined using surface potential decay measurement. The aging was carried out by exposing the specimens to corona stress generated by a high-frequency AC multi needle-plane electrode system. The results show that the addition of alumina filler increases the surface potential decay time and maximum trap energy. A reduction in trap depth is observed with the corona aging, and the addition of alumina filler limits the degradation and change in charge trap distribution. The results of an analysis of the space charge behavior of different nanocomposites and their comparison are presented. The space charge variation analysis was carried out under the applied electric field of 20 kV/mm at room temperature using the pulsed electro-acoustic technique (PEA). Based on the results, the charge density, electric field, and charge trap distribution were deduced. It is concluded that the space charge concentration and enhancement in the electric field of the aged material increases with aging duration and it is maximum in the case of 60 min corona-aged pure silicone rubber. Analysis of the recovery of the charge dynamics of the sample after corona discharges at the different time intervals shows that the recovery of trap distribution is faster for a virgin sample and slower for the sample with 5 wt% of alumina.