Anodising AA5083 aluminium alloy using ionic liquids

Aluminium, as the current collector in lithium batteries, has shown reduced corrosion susceptibility in room temperature molten salts (1, 2). Moreover, previous studies have established that corrosion mitigation is achieved on magnesium alloys using ionic liquids pretreatments (3, 4). This paper investigated the anodisation of AA5083 aluminium alloy in Trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfony) ([P6,6,6,14][NTf2]) ionic liquid by applying a constant current followed by holding at the maximum potential for a period of time. Potentiodynamic polarisation results show that the treated surfaces were more corrosion resistant in 0.1 M sodium chloride solution compared with the control specimen. The anodising treatment was effective both in shifting the free corrosion potential to more noble values and in suppressing the corrosion current. Optical microscope and optical profilometry images indicated that an anodising film was deposited onto the alloy surface, which is thought to have inhibited corrosion in chloride environment. Further characterisation of the anodising film will be carried out in future work.