Scanning Kelvin Probe applied to localised corrosion

Abstract

This paper focuses on specific applications of the SKP system. The instrument is calibrated, using different thickness of a model polymer Poly Vinyl Butyral (PVB) on mild steel and on galvanised steel. Artificial defects are used to show how the instrument is capable of detecting a localised corrosion cell and its ability to picture the delamination of the coating from the steel substrate. An industrial application is undertaken with the instrument, where epoxy coated galvanised steel; with an introduced defect in the coating and various added inhibitors. Chromates and chromate replacements have been studied.