Sequential RTV/(TiO2/SiO2) nanocomposite deposition for suppressing the leakage current in silicone rubber insulators

The sequential deposition method is introduced for suppressing the leakage current in silicone rubber insulators. Room temperature vulcanizing silicone and TiO2/silica nanocomposites are sequentially deposited on silicone insulators surface. TEM results showed that TiO2 nanoparticles size is about 20-30 nm, and the structural study revealed their anatase crystalline structure. Silica nanoparticles are deposited on the surface of insulators by spray deposition. The contact angle was enhanced from 104 degrees to 149 degrees after nanoparticles deposition, which confirms the hydrophobicity improvement. Results show that leakage current for nanocomposite samples in a contaminated environment reduced to about 0.02 mA, which was 1 mA in insulators without any coating, indicating a remarkable improvement after coating. The stability of bare and coated insulators was examined under kaolin, salt, NH4Cl-contaminated environment, and also UV radiation for more than 500 h. Results show that the sequential deposition could be utilized as a cost-effective and scalable method for enhancing the hydrophobicity and stability of insulators.