Enhancement of Silicone Coatings Performance to Deal with the Effects of Air Pollution on the Efficiency of Electrical Applications
Subject Areas :
Sahar Abdollahi Baghban
1
,
Narges Rabbanikhah
2
1 -
2 - Department of Polymer and Color Engineering, Amirkabir University of Technology, Tehran, Iran.
Keywords: Silicon-rubber, hydrophobic and self-cleaning coatings, Surface modification, Micro and nanoparticles, Electrical Insulator.,
Abstract :
This review article examines the methods for improving the performance of silicone coatings for electrical insulators under harsh and polluted environmental conditions. To improve the properties of silicone coatings, the application of micrometric, nanometric, and mixed micro/nanoparticle fillers (inorganic oxides: silica, nanoclay, CaCO3, ZnO, TiO2, Ta2O5, Co3O4, SnO2, aluminum nitride (AlN), boron nitride, barium titanate, aluminum trihydroxide (ATH) and organic fillers: carbon nanotubes (CNT), multi-walled CNTs, montmorillonite, and graphene oxide) have been investigated. The results revealed that the introduction of nano and micro fillers with optimal ratios such as micro and nanoparticles of silica and AlN in the coating improved the mechanical and tensile strength of the coatings, increased the superhydrophobicity, reduced the effects of aging and degradation caused by UV radiation, thermal and pollution erosion, improved the dielectric strength and surface stability against electrical discharge, reduced the leakage current, and also increased the tracking resistance. Consequently, it was reported that silicone-rubber-ethylene propylene diene monomer rubber coatings containing modified silica nanoparticles, ATH, UV stabilizers, and silicone oil, demonstrated the highest hydrophobicity with improved surface roughness and self-cleaning properties (water drop contact angle: 161º). Accordingly, these coatings are suitable for high-voltage insulators with high performance (volume resistivity 1.5×1017 (Ω.cm), surface resistivity 1.5×1012 (Ω.cm), tracking resistance:500 minutes at 5 KV, breakdown voltage: 145 KV, dielectric constant: 4.4, high fire resistance up to 340 ºC and long service at elevated temperatures) without the requirement for frequent cleaning.