Hot-dip zinc-coated steel sheets are used as an outdoor industrial material, but they corrode because of acid rain.
In this study, the corrosion process of hot-dip zinc-coated steel sheets in simulated acid rain solution with in-situ Raman spectroscopy has been studied.
The current density of specimen decreased with constant potential holding at −0.6V vs. Ag/AgCl in simulated acid rain solution. And, the main peak, ZnSO4·7H2O was detected with in-situ Raman spectroscopy at the time of decreasing current density. Therefore, it is considered to be the case that the following equation describes the reactions that occurred.
Zn2++SO42−+7H2O→ZnSO4·7H2O.
The current density was decreased by ZnSO4·7H2O because the growth of ZnSO4·7H2O covered surface area of the specimen.
Hot-dip zinc-coated steel sheets showed an anticorrosive effect as a result of the hot-dip zinc-coating layer being dissolved by a sacrificial anode function, and ZnSO4·7H2O was formed in the simulated acid rain solution.
