The analysis of aging characteristics of RTV insulating coatings with varying silicone rubber contents

Abstract Room-temperature vulcanized silicone rubber coatings are widely used in the field of high-voltage outdoor insulation. Silicone rubber (RTV-SIR) coatings are used to improve the anti-pollution flashover performance of high-voltage ceramic insulators by imparting hydrophobicity to the surface. Different high-temperature aging experiments were conducted on coating samples with varying silicone rubber contents, and their physicochemical properties were tested to analyze the aging mechanisms involved, aiming to further evaluate the lifespan of the coatings. It was observed that lower silicone rubber content led to more significant changes in surface functional groups, accelerated degradation of coating properties during aging, and increased susceptibility to microcrack formation and subsequent crack development, further promoting the aging process. The aging process accelerated gradually from the surface to deeper layers at the same temperature, resulting in increased disorder and densification of the three-dimensional network structure, along with fragmentation of low-molecular-weight molecules.