Surface studies of conversion coated steel after corrosion induced paint deadhesion

Secondary ion mass spectorscopy (SIMS) and scanning electron microscopy (SEM) have been used to characterize the surface composition and morphology of zinc‐phosphated steel before application of organic coatings and after corrosion‐induced delamination of these coatings. Imaging SIMS and SEM results confirm the presence of a cystalline zinc‐iron‐phosphate layer on the phosphated steel before coating application. During the corrosion process, dissolution of the crystal structure occurs between the initial corrosion site and the progressing edge of corrosion induced delamination. Beyond this edge the crystal structure remains intact.