Hydrogen Permeation Behavior of Scratch on Zn Coated Steel during 1000 Hours Wet and Dry Corrosion Test

Abstract

In this study, hydrogen permeation current from scratch formed on Zn coated steel during 1 000 h wet and dry cyclic corrosion test was investigated. The scratch was fabricated by focused pulsed Nd: YAG laser irradiation. The obtained hydrogen permeation current has peaks during wetting, and the peak currents decrease with time. Formation of Zn corrosion products prevent hydrogen entry. After the test, there are Zn oxide (ZnO) on the substrate steel, hydrozincite (Zn 5 (OH) 6 (CO 3 ) 2 ) around the scratch boundary and simonkolleite (Zn 5 (OH) 8 Cl 2 ) on Zn coated region. It is suggested that pH change with distance from the formed scratch is the reason for the composition of Zn corrosion products change with location.