Effect of UV Irradiation on the Alternating Wet and Dry Corrosion Behavior of Galvanized Steel in Sodium Chloride Solution

Abstract

In this paper, the corrosion performance of galvanized steel was investigated in a simulated marine environment, under UV irradiation coupling with an alternating wet and dry cycle in a NaCl solution. The surface morphology, composition, and corrosion performance of galvanized steel before and after different alternating wet and dry corrosion under UV irradiation were investigated. The results show that the corrosion current density gradually increases and the corrosion resistance decreases as a function of the alternating wet and dry corrosion cycles. Meanwhile, UV irradiation accelerates the increase in the corrosion current density and the decrease in the corrosion resistance. In addition, the corrosion product ZnO shows a semiconductor property, and the photo-induced electrons and holes produced under UV can participate in the corrosion reaction and promote the formation of loose corrosion products Zn(OH)2, Zn5(OH)8Cl2, and Al2Cl3(OH)5·4H2O, thus accelerating the corrosion of galvanized steel in the atmosphere environment.