Nano Mica/Silicone Coating on Electrical Porcelain Substrate

The study explores the use of nano mica platelets as a filler in silicone matrix for developing silicone-based coating on porcelains insulators. The protocol for hydrophobic surface treatment of fillers with hexamethyldisilazane and coating technique employed on porcelain substrate is detailed. An experimental approach is adopted, beginning with Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) to confirm the successful filler surface silane treatment. Energy dispersive X-ray fluorescence (EDXRF) and energy dispersive X-ray (EDAX) analysis revealed the presence of insulating oxides—alumina and silica, along with various other semi-conductive oxides. Scanning electron microscopy (SEM) images revealed smooth mica platelet surfaces with cleaved structures. The stacked platelet morphology is revealed in the transmission electron microscopy (TEM) images. Static contact angle improved from 48.73° for porcelain substrate to 93.55° at 5 phr loading. Doping with mica fillers enhanced the volume resistivity by a decade over neat silicone. Dielectric constant and dissipation factor improved with the addition of nano mica platelets. ac and dc (bipolar) dielectric strength improved tremendously even at a mere 0.5 phr nano mica doping by 1.22, 1.26, and 1.27 times over neat silicone for ac, +dc, and −dc dielectric strength, respectively. The results are presented and discussed here.