Melitta Hon

‘Smart’ corrosion inhibiting coatings

Abstract Under certain conditions, the driving force of corrosion produces protective oxide films, a process typically referred to as passivity. In cases where passivity is difficult to achieve, for example, for Al alloys in neutral NaCl solutions, it is conceivable that a ‘smart’ coating can be micro- or nano-engineered to use the energy of the corrosion to generate ‘on demand’ a corrosion inhibitor for stopping or slowing corrosion at defects. Work at Rockwell Scientific provides evidence that anionic inhibitors for the oxygen reduction reaction (ORR), when used as dopants for conducting polyaniline (PANI) films, inhibit corrosion of a Al 2024-T3 substrate at a scribe. In effect, the scribe polarizes the PANI causing it to release the inhibitor.

A Hydrotalcite-Like Pigment Containing an Organic Anion Corrosion Inhibitor

An organic anion exchanged hydrotalcite-like inhibitor was synthesized using an approach similar to that described previously by Williams and McMurray and characterized as to its ability to inhibit the oxygen reduction reaction on a Cu rotating disk electrode. The results suggest that this new inhibiting pigment would effectively inhibit filiform corrosion in alloys such as AA 2024-T3.