Corrosion inhibitors for anodised aluminium

• Corrosion inhibitors are used to impart anti corrosion activity to anodised aluminium.
• Inhibitors chelate copper in anodic oxide increasing the corrosion resistance.
• Corrosion resistance increased with the inclusion of tetrazine molecules.
• Inhibitor soaked with hydrothermal seal significantly increases corrosion resistance.

A novel sealing process for anodised aluminium has been developed based on inclusion of environmentally compliant corrosion inhibitors. Nanoporous oxide films formed by sulphuric acid anodising on aerospace grade AA2024-T3 have been sealed with a combination of corrosion inhibitors and surface hydration. The corrosion resistance was evaluated using electrochemical impedance spectroscopy and accelerated corrosion testing in a neutral salt spray environment. The synergistic anti-corrosion mechanism of the inhibitors within the oxide film on the corrosion prone alloy was determined. The technique described offers numerous opportunities for industrial applications.