Studies of surface treatment of aluminum alloys by BTSE silane agent

Silane films prepared from bis-1, 2-[triethoxysilyl] ethane (BTSE) hydrolyzed in ethanol/water mixture on LY12 aluminum. alloys were characterized by dc-polarization curves and electrochemical impedance spectroscopy (EIS) in NaCl solution. The presence of silane films obviously improves the corrosion protection of alloys. The similar electrode kinetics of Al alloys in NaCl electrolyte were observed in the absence and in the presence of BTSE films, indicating that the silane films only act as a barrier against the attack of corrosive species. A suitable equivalent electrical circuit (EEC) for silanized samples was proposed and used throughout the work to fit the EIS data. The optimum processes of BTSE films were obtained from the orthogonal design. The corrosion protection was quantitatively evaluated by polarization resistance (R-p) of alloy electrodes derived from EIS measurements. The effect of each factor on film performance was also discussed.