Corrosion of aluminium in copper–aluminium couples under a marine environment: Influence of polyaniline deposited onto copper

In this study, we examined how aluminium corrosion in Al–Cu/PANI galvanic couples in a marine environment is influenced by deposition of polyaniline (PANI) on copper. Polarization curves and immersion assays in 0.1 M NaCl were performed. The morphologies of etched Al and corrosion products were observed by SEM, and the Al ions in solution were quantified by atomic absorption spectroscopy. A reduction in aluminium damage due to galvanic corrosion was observed as a result of decreased effective area for the oxygen reduction reaction on Cu/PANI electrode. Furthermore, an electrochemical reduction of PANI from leucoemeraldine to emeraldine base is proposed.

Research highlights
► The presence of Polyaniline in the Al–Cu system produces a decrease in the oxygen reduction reaction.
► In the marine enviroment, aluminium in Al–Cu couples, suffers pitting and exfoliation.
► The aluminium deterioration increases with chloride and enviromental sulphur dioxide presence, mainly when it is united to bare copper.