Smart ceramic coatings for corrosion protection – pdf

Smart coatings have the ability to interact with the environment, responding selectively to certain triggers, such as mechanical fracture, temperature or pH variations. Depending on the type of functionalisation different properties can be achieved, e.g. specific corrosion inhibition, self-healing or self-cleaning properties. This technology is widespread in the field of polymeric coatings, where the organic matrix can be easily functionalised; however, their applicability is limited to mild environments, since they usually present relatively low thermal and tribological resistance.

The scientific question proposed in this work is whether incorporating smart functionality is feasible in ceramic-based coatings produced by Plasma Electrolytic Oxidation (PEO). Such coatings present excellent performance in demanding conditions, but active functionalisation is highly challenging given the rigid and inert nature of inorganic matrices compared to organic materials. For that, the formulation of the coating includes nanocontainers loaded with corrosion inhibitors, which will be incorporated into the porosity of the coatings. The inhibitors are released from their nanocontainers in response to pH changes arising from electrochemical activity associated with corrosion initiation and will act locally at the anodic and/or cathodic sites inhibiting corrosion propagation.