Two types of protective silane films, bis-1, 2-
ethane (BTSE) and dodecyltrimethoxysilane (DTMS), were deposited
on LY12 aluminum alloys with aiding of electrochemical technique. Electrochemical impedance spectroscopy (EIS) tests show that after silanization the corrosion resistances of Al alloys are increased significantly, especially after deposition at cathodic potentials. A critical deposition potential (CDP), namely -0.8 V, is generally found for each silane system, at which the highest protectiveness is obtained. Scanning electron microscopy (SEM) shows that silane films prepared at CDP display the highest uniformity and density. Applying more positive potentials does not facilitate the film formation. On the other hand, when potential shifts more negative the surface of films presents porous morphology, probably due to the intensive evolving of hydrogen bubbling near the surface. Due to the presence of long hydrophobic Dodecyl chain in bone structure, DTMS films display the best barrier properties.