The corrosion resistance of hot dip galvanized steel pretreated with Bis-functional silanes modified with microsilica

The present work aims at understanding the corrosion behaviour of hot dip galvanized steel pretreated with either bis-1,2-[triethoxysilyl]ethane silane (BTSE) or bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) modified with microparticles of SiO2. The corrosion resistance was evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and by the scanning vibrational electrode technique (SVET) during immersion in dilute NaCl solutions. The films formed on the galvanized steel substrate were characterized by X-ray photoelectron spectroscopy, Auger electron spectroscopy and atomic force microscopy. The results show that the pretreatments based on silane films modified with silica particles provide corrosion protection for hot dip galvanized steel during immersion in NaCl-containing solutions.