Effects of addition of corrosion inhibitors to silane films on the performance of AA2024-T3 in a 0.5M NaCl solution

Water-based organofunctional silanes have been successfully used as an alternative to toxic chromate coatings for surface pre-treatment of metals and alloys. To further improve the performance of these silane films, corrosion inhibitors were added to the silane films and their corrosion properties investigated in 0.5 M NaCl solution. The inhibitors used were environmentally acceptable organic (tolyltriazole, benzotriazole) molecules and inorganic cerium salts. In the first part of the paper we discuss the inhibition efficiency of the individual inhibitor on the corrosion of AA2024-T3 alloy to understand the mechanisms of inhibition offered by these inhibitors. All of the above mentioned inhibitors effectively protected AA2024-T3 alloy against corrosion when immersed in a 0.5 M NaCl solution containing these inhibitors. In the second part of the paper the effects of the addition of inhibitors to silane films was investigated. The results indicate that these inhibitors are slowly leached out and thus further improve the corrosion protection by silane films and the inorganic inhibitors show promise of self-healing of defects. (c) 2005 Elsevier B.V. All rights reserved.