Optimization of coil coating systems by means of electrochemical impedancespectroscopy

Corrosion protection of coil-coated hot-dip galvanized (HDG) sheets against aggressive environments depends on several factors linked to galvanizing, chemical conversion, passivation, primer, topcoat. Each component gives a c ontribution to the final anticorrosive performance of the coated product. T he study of such a complex system needs proper sample assessments and power ful experimental techniques. The present paper deals with the study of a si gnificant number of systems using a particular approach based on the analys is of the impedance data at one characteristic frequency. (C) 1999 Elsevier Science Ltd. All rights reserved.