Electrochemical behavior and corrosion protection performance of bis-[triethoxysilylpropyl] tetrasulfide silane films modified with TiO2 sol on 304 stainless steel

The corrosion protection ability of bis-[triethoxysilylpropyl]tetrasulfide/TiO2 composite films was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in this paper. The electrochemical results show that the composite films modified with TiO2 sol exhibited superior corrosion protection performance compared to single bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) silane films. The durability and reaction mechanism of BTESPT films and BTESPT/TiO2 composite films were further studied by electrochemical impedance spectroscopy, scanning electron microscopy, reflection absorption Fourier infrared spectroscopy and X-ray photoelectron spectroscopy, the experimental results revealed the loading of TiO2 sol into the porous part of the silane network, which not only increases the compactness and durability of silane films but also improves the interfacial bonding force due to formation of SiOTi bonds. After 15 days immersion in 3.5 wt.% NaCl solution, the BTESPT/TiO2 composite films still had good corrosion resistance ability.