A review of physical properties of hot-dip galvanized coating layer by layer and their respective electrochemical corrosion behavior

Abstract

PurposeThis paper aims to contribute to the performance improvement and the broader application of hot-dip galvanized coating.Design/methodology/approachFirst, the ability to provide barrier protection, galvanic protection, and corrosion product protection provided by hot-dip galvanized coating is introduced. Then, according to the varying Fe content, the growth process of each sublayer within the hot-dip galvanized coating, as well as their respective microstructures and physical properties, is presented. Finally, the electrochemical corrosion behaviors of the different sublayers are analyzed.FindingsThe hot-dip galvanized coating is composed of η-Zn sublayer, ζ-FeZn13 sublayer, δ-FeZn10 sublayer, and Γ-Fe3Zn10 sublayer. Among these sublayers, with the increase in Fe content, the corrosion potential moves in a noble direction.Research limitations/implicationsThere is a lack of research on the corrosion behavior of each sublayer of hot-dip galvanized coating in different electrolytes.Practical implicationsIt provides theoretical guidance for the microstructure control and performance improvement of hot-dip galvanized coatings.Originality/valueThe formation mechanism, coating properties, and corrosion behavior of different sublayers in hot-dip galvanized coating are expounded, which offers novel insights and directions for future research.