Abstract
The primary function of Zn coatings is based on galvanic protection of the underlying steel substrates from corrosion damages in aqueous/atmospheric conditions. On the other hand, the sacrificial dissolution properties of Zn-based coatings can also be the primary driving force for hydrogen evolution on a steel surface. In particular, once the coatings are damaged, large cathodic overpotential can be applied on the exposed steel substrate, promoting hydrogen evolution via H2O reduction. Our work shows that the hydrogen evolution and absorption behaviors can be controlled greatly by the corrosion-induced damage characteristics of the coating layers. The significant differences in hydrogen evolution, penetration, and cracking behaviors between the two types of Zn coatings: galvanized (GI) and galvannealed (GA) coatings, in a neutral aqueous environment, are discussed in this presentation.