Studies on the film forming behaviour of mercapto-based compounds for corrosion inhibition of AA2024-T3

Structural Aluminium alloys widely used in aerospace, automotive and marine applications are susceptible to various forms of corrosion. Corrosion protection of these alloys is commonly achieved through protective coatings and the employment of corrosion inhibitors. Despite the extensive amount of studies on the evaluation of inhibitor performance, limited work has been done on understanding film-forming characteristics of inhibitors and their role in providing corrosion protection, thus providing the basis for this investigation.In this study, key aspects of the film forming behaviour of a mercapto-based inhibitor on aluminium alloy, AA2024-T3 in aqueous 0.1 M chloride solution are investigated. A variety of electrochemical corrosion testing methodologies and surface characterisation techniques are employed in conjunction with each other. A major focus of this study is to draw correlations from both the electrochemical data and surface analysis results to evaluate the nature of film formation and film decay, change in resistance with film build-up and in particular, the persistence of the inhibitor-induced film once it has been developed over the metal surface.