Corrosion is an omnipresent phenomenon in materials science and technology as well as in our everyday life. The need to fully understand corrosion processes and to search for novel coating protection to prolongate the lifetime of materials is high.
Scanning probe techniques, such as SECM can be employed to study local corrosion processes as well as the quality of coatings with sub-micrometer resolution (determined by the size of the used microelectrode). It can provide information about local reactivity in-situ and therefore identify precursor sites of pitting corrosion. The imaging of coated surfaces provides information about defects (cracks, pores, pinholes) within the coating or generally heterogeneous permeability. Also, active corrosion can be mapped by detection of released species.
Usually SECM works in amperometric mode tracking changes in current above the sample. If the concern arises that this might lead to local changes of conditions right above the investigated sample, potentiometric methods can be employed e.g. to study the local corrosion potential (open-circuit potential).