Preparation of Nano-SiO2-Coated Graphite Films by a Laser-Assisted Sol–Gel Process

Abstract

Here, we prepared nano-SiO2-coated graphite films using a novel laser-assisted sol–gel method. The SiO2 sol–gel prepositioned on the graphite substrate was irradiated by the fiber laser at different energy densities. The growth mechanism of the coatings under laser irradiation was studied and the effects of processing parameters on the coating structure were systematically investigated. In addition, the high-temperature oxidation resistance of these samples was examined. Surface morphology and elemental composition were examined using scanning electron microscopy and energy-dispersive spectrometer. Phase constituents and microstructure were identified by x-ray diffraction and transmission electron microscopy. The oxidation resistance was analyzed by thermal gravimetric analysis. The results found that laser irradiation significantly modifies the sol–gel-deposited nano-SiO2 layer. A uniform and compact nano-SiO2 coating was obtained when irradiated by laser energy density of 14.4 kJ/cm2. Optimum high-temperature oxidation resistance was achieved for the two-layer SiO2-coated films.