Effect of Corrosive Aging on the Surface Charge Dissipation Characteristics of Silicone Rubber

Silicone rubber composite insulators are critical components of outdoor insulation systems. However, prolonged exposure to acidic, alkaline, and saline contaminants can lead to severe corrosion of the silicone rubber sheds, ultimately degrading the insulators’ electrical performance. In this study, silicone rubber samples are subjected to artificial accelerated aging in HNO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>, NaCl, and NaOH solutions, and the effects of different corrosive aging conditions on surface charge dissipation characteristics were systematically investigated. The results reveal that unaged silicone rubber exhibited significant surface charge accumulation and a relatively slow dissipation rate. Compared to unaged samples, aged silicone rubber demonstrated a reduction in the time required for the positive and negative average surface charge density to decay to 70% of the initial value, ranging from 7.53% to 30.14% and 1.89% to 23.70%, respectively. NaOH solution caused more severe microstructural damage to the silicone rubber than HNO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>, whereas samples aged in HNO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> solution exhibited the least surface charge accumulation. Further analysis of surface conductivity and trap density measurements reveals that the surface conductivity of silicone rubber increased by 110.06%, 1.69%, and 1.04% after aging in HNO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>, NaCl, and NaOH solutions, respectively. Additionally, the density of shallow traps increased by 87.50%, 12.34%, and 7.81% compared to unaged samples. These findings provide critical guidance for refining the aging assessment of silicone rubber materials under complex environmental conditions.