SCANNING REFERENCE ELECTRODE TECHNIQUE AS TOOL FOR INVESTIGATING LOCALIZED CORROSION PHENOMENA IN GALVANIZED STEELS

A scanning reference electrode technique (SRET) is described which is sufficiently stable and sensitive as to allow the automatic acquisitio n of time lapse isopotential contour maps of localised corrosion pheno mena occurring in contact with molar concentrations of aqueous electro lyte. The SRET is demonstrated to be a useful tool for the investigati on of time dependent galvanic corrosion processes occurring in the reg ion of coating defects and cut edges on galvanised sheet steel immerse d in neutral aqueous sodium chloride. The technique is also shown to b e capable of revealing distinct differences in the localised selfcorro sion behaviour of various zinc alloy coatings.