Scanning electrochemical microscopy for the investigation of localized degradation processes in coated metals

Scanning electrochemical microscopy has been employed to obtain spatially-resolved information regarding surface topology, water uptake and blister formation at intact coatings, as well as the onset and progress of corrosion reactions within coating defects. Topographical lines and maps as well as chronoamperometric plots were measured during operation in the feedback mode. Next, the release of metal ions at the anodic sites and the consumption of oxygen at the cathodic sites developed in holidays could be monitored during operation in the generator–collector mode. Furthermore, the surface topography of defective coatings was imaged by using the redox competition mode.