The influence of moist environments on the aging performance of silicone rubber (SR) used for outdoor insulation was investigated by a salt-fog test. High-temperature vulcanized (HTV) SRs with different alumina trihydrate (ATH) filler contents were adopted as the test specimens. For the test of a single water droplet, the vibration and elongation of the water droplet caused a flashover, and the flashover voltage decreased with increasing ATH content. In the first cycle of the salt-fog test, the leakage current increased with increasing ATH content. The relatively higher hydrophobicity of the specimen with a low ATH content than the specimen with a high ATH content had an inhibitory effect on the initial leakage current development. In the last cycle of the salt-fog test, the heat from dry band arc discharge became the dominant factor affecting the surface aging after the loss of hydrophobicity, and the specimen with a higher ATH content inversely had a better inhibitory effect on leakage current development. According to the X-ray photoelectron spectroscopy (XPS) analysis results, when the energized SR was exposed to a moist environment, the heat from dry band arc discharge and the hydrolysis reaction caused a change in the binding state between Si and O, which is considered the mechanism responsible for material degradation. During this process, the higher content of ATH had a remarkable effect on alleviating surface aging.INDEX TERMS Moist environment, silicone rubber, hydrophobicity, dry band arc discharge, aging performance.

A new generation of high performance polysiloxane white coating has been peeling off a large area after being applied on a special ship for 10 years, which has a great impact on the appearance of the hull. Based on the curing mechanism and physicochemical characteristics of acrylic polysiloxane coating, the reason of existing coating stripping was analyzed. Through a small range test, We can explore the method of coating repair.

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