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.

Effect of Corrosion Product on the Electrochemical Behavior of Zn, Zn-Al and Al-Mg-Si Alloy Coated Steel

“…10 The microstructure of hot dipped Zn coating is composed of a single-phase microstructure. The analysis of hot dipped indicated that the coating surface consisted of two principle phase in its microstructure.…”