ASSESSMENT OF CORROSION BEHAVIOUR OF SOME ALUMINIUM ALLOYS VIA ELECTROCHEMICAL AND FREE CORROSION TESTS IN ACIDIC AND NEUTRAL ENVIRONMENTS

The corrosion behaviour of four commercial aluminium alloys, extensively employed in engineering applications, was evaluated by means of electrochemical and free corrosion tests in order to compare their performances in both acidic and neutral environments. The electrochemical parameters obtained via cyclic potentiodynamic polarisation were compared with the corrosion features observed on these alloys after free corrosion tests. Different morphologies and damage extents were identified on these samples and upon the aggressive environment and the results were related to the chemical composition of the alloy and the corrosion and passivation mechanisms.