Influence of surface pretreatments on the corrosion protection of sol-gel coated AA2024-T3 aluminium alloy

In the present study, the effects of surface pretreatments of AA2024 aluminium alloy on the corrosion protection of the alloy using a sol-gel coating were investigated. It was revealed that the second phase particles that remain after etching and desmutting have a significant impact on the subsequent sol-gel coating which, in turn, influences the overall corrosion protection afforded to the substrate by the sol-gel coating. The removal of second phase particles in the surface region can be achieved by an alternative surface pretreatment using nitric acid. A significant improvement of corrosion protection of sol-gel coated AA2024 aluminium alloy was observed when the surface of the alloy was pretreated with nitric acid. Copyright (c) 2013 John Wiley & Sons, Ltd.