Preparation of porous composite coatings to suppress surface charge movement and reduce electrical resistivity

Abstract

In this work, CrO/TiO composite coatings were prepared on -AlO insulating ceramic matrix surface by screen printing and solid phase sintering methods to yield an average film thickness of about 14.10 μm. Scanning electron microscopy (SEM) revealed changes in the pore structures of the coatings at different TiO contents. The atomic force microscopy (AFM) analysis of the coating surface roughness suggested a TiO content of 0.025 mol to yield the best surface roughness and pore structure of the coating. The calculation showed an increase in the energy level of the deep trap center on the surface from 1.506 eV to 1.547 eV, reaching a maximum. The surface resistivity of insulating ceramics decreased from 10 Ω to 10 Ω. The formation of deep surface traps and the decrease in surface resistivity promoted charge dispersion and suppressed the formation of flashover channels, effectively improving the surface flashover voltage of the ceramics.