SECM study of steel corrosion under scratched microencapsulated epoxy resin

Scratch tests were performed on epoxy coated steel samples with and without microcapsulated linseed oil, known to develop a polymerized protective layer after having been released from the capsules at the damaged sites. The scanning electrochemical microscope has been applied to monitor the protection efficiency of this self-healing coating in aqueous acidic solution. In the proximity of the local damage, both the anodic metal dissolution and the cathodic oxygen reduction showed that the coating with microcapsules substantially and spontaneously decreased the rate of corrosion proving the self-repair concept of the coating. Electrochemical impedance measurements underline the protective effect of the coating as well.

► Epoxy coatings with microcapsulated linseed oil were prepared on steel samples.
► Scratch tests were performed on the coated samples.
► Deterioration of steel sheets in solution of NaClO4 and HClO4 were monitored.
► Self-healing effect of the oil was followed by scanning electrochemical microscopy.
► The decreased rate of corrosion proved the self-repair concept of the coating.