A study on the effect of environmental stresses on the hydrophobic characteristics and field performance of RTV silicone rubber coatings

This paper presents the results of a study on the hydrophobic characteristics of Room Temperature Vulcanizing (RTV) silicone rubber coatings exposed to accelerated weathering in several degrading environments. Accelerated climatic stresses (UV light, rain), thermal treatment, ozone atmospheres and chemical oxidation were used to simulate aging. The dynamic behavior of the hydrophobicity recovery on both corona-treated and artificially polluted RTV coating surfaces was studied. The flashover performance of coated cap-and-pin insulators was evaluated after exposure of the coating to a chemically oxidizing environment. The physical changes occurring on the coating surface as a consequence of aging and its effect on the property of hydrophobicity recovery and on the electrical performance of coated ceramic insulators are analyzed and discussed.