An investigation on the atomic oxygen erosion resistance of surface sol–gel silica films

Ultrathin silica films were deposited on Kapton substrate by surface sol–gel (SSG) method and their atomic oxygen (AO) erosion resistance was tested in a ground-based AO simulator. The surface morphology and structure of silica films were investigated by atomic force microscopy, scanning electronic microscope, Fourier transformed infrared spectroscopy, and X-ray photoelectron spectroscopy. The results indicate that the silica films grow on Kapton substrate in an island-like manner. As the depositing cycle increases, silica films tend to become dense and smooth. The film structure is found to be not an exact equilibrium SiO2 structure. Under AO environment, the AO erosion resistance of silica-modified Kapton is improved and enhances as the depositing cycle increases. It is noted that the silica-modified Kapton with 10 cycles shows the best AO resistance and its erosion yield is two orders of magnitude less than that of pristine Katpon. The AO erosion mechanism of silica films is analyzed in the paper.