Communication - an approach to measuring local electrochemical impedance for monitoring cathodic disbondment of coatings

An electrochemically integrated multi-electrode array has been used for monitoring and visualizing the cathodic disbondment of defective coatings by measuring local electrochemical impedance. Compared with the conventional electrochemical impedance and local current measurement approaches, this new approach significantly enhances the sensitivity of detecting the propagation of coating disbondment by eliminating the effects of the dominating low impedance regions, such as those that arise at coating defects, and thus increases the visibility of higher impedance regions deep in the disbonded coating. Furthermore, it facilitates the probing of electrode processes and mechanisms in selected local electrode regions.