Effect of scratching of coating surface on the electrochemical behavior of PVD Al-Mg-Si coated steel

Abstract

Effect of scratching of coating surface on the electrochemical behavior of PVD Al-Mg-Si coated steel has been investigated using an open circuit potential (OCP), anodic polarization and galvanic couple test. The OCP monitoring showed a fast ennoblement of OCP then attained a steady state value during the last stage of monitoring. There were two types of corrosion products of scratched coating that protected from continuous corrosion and act as selfhealing. The first is passive film that arises from the adjacent coating surface on both sides of scratched area and covering the underlying steel. The second is corrosion product produced by the corrosion of steel on scratched area. © The Electrochemical Society of Japan, All rights reserved.