Design and investigation of TiO2 - SiO2 thin films on AISI 316L stainless steel for tribological properties and corrosion protection

The TiO2–SiO2 thin films were deposited on AISI 316L stainless steel via sol-gel method. Then, the effect of the added amount of SiO2 on the structure, morphology and mechanical properties of the films and corrosion behavior of AISI 316L stainless steel substrate were investigated. So, X-ray diffraction, field-emission scanning electron microscopy, atomic force microscopy, depth-sensing indentation technique supporting micro-scratch mode and potentiodynamic polarization test were used. It was observed that the appropriate amount SiO2 addition into TiO2 film not only decreased the particle size of TiO2–SiO2 crystal but also could help to improve the surface quality. The mechanical and tribological properties of the films were found to be improved in the range of 10–15%mol SiO2 addition compared with the pure TiO2. The minimum root mean square value was obtained from the film with a silica content of 10%mol. In addition, the corrosion behavior of AISI 316L stainless steel was improved by adding 15%mol SiO2. Under UV illumination conditions, photo-generated electrons accumulated in this film could perfectly protect the substrate photocathodically.