The surface and electrochemical analysis of permanganate based conversion coating on alclad and unclad 2024 alloy

► Permanganate based conversion coatings were developed on 2024 alloy surface with and without alclad layer. ► To identify the compounds formed and the chemical state on the coated surfaces the Raman spectra and XPS analysis have been utilized. ► Electrochemical behaviour of all the coated surfaces was evaluated by standard methods for longer immersion durations. ► Developed alternate to chromate conversion coating on alclad specimen showed uniform and compact with higher corrosion resistance. ► A plausible pictorial representation of the corrosion reaction mechanism for the unclad coating surface had been given.