The effect of inhibitor structure on the corrosion of AA2024 and AA7075

A range of structurally-related compounds were tested for their capacity to inhibit corrosion on aluminium alloys AA2024-T3 and AA7075-T6 in 0.1 M NaCl solution. It was found that the thiol group, positions para- and ortho- to a carboxylate, and substitution of N for C in certain positions strongly inhibited corrosion. The hydroxyl group was slightly inhibitive, while the carboxylate group provided little or no corrosion inhibition on its own. In several cases, different activities were found on the different alloys, with some compounds (particularly thiol-containing compounds) being more effective on AA2024 than on AA7075.

► Organic compounds as replacements for chromate corrosion inhibitors for Al alloys. ► Effect of structure of organics on inhibition efficiency on Al poorly understood. ► Wide range of structurally-related organics tested in NaCl solution for inhibition. ► The effect of individual structural components analysed. ► Several new or little-known compounds identified as excellent corrosion inhibitors.