The inhibitive action of metacryloxypropylmethoxysilane (MAOS) on aluminium corrosion in NaCl solutions

The inhibitive action of MAOS (metacryloxypropylmethoxysilane) used for sil anising pretreatment on aluminium corrosion in NaCl aqueous 3.5% solutions has been examined. Free corrosion and electrochemical tests (potentiodynamic polarisation and electrochemical impedance) were performed to characterise the resistance of pre-treated specimens against general and localised corrosion. The surface of the specimens was examined by XPS, FT/IR and optical microsc opy before and after immersion in NaCl solution. It was found that silanising inhibits general and localised corrosion of al uminium because of the formation of an Al-siloxane polymeric film, the inhi bitive action of which increases with increasing immersion time due to the synergistic effect of aluminium oxides precipitated as corrosion products o n aluminium surfaces. (C) 1999 Elsevier Science Ltd. All rights reserved.