Corrosion kinetics and patina evolution of galvanized steel in a simulated coastal-industrial atmosphere

Abstract The corrosion kinetics and patina (corrosion products) layer evolution of galvanized steel submitted to wet/dry cyclic corrosion test in a simulated coastal-industrial atmosphere was investigated. The results show that zinc coating has a greater corrosion rate during the initial period and a lower corrosion rate during the subsequent period, and the patina composition and structure can greatly affect the corrosion kinetics evolution of zinc coating. Moreover, Zn 5 (OH) 6 (CO 3 ) 2 and Zn 4 (OH) 6 SO 4 are identified as the main stable composition and exhibit an increasing relative amount; while Zn 12 (OH) 15 Cl 3 (SO 4 ) 3 cannot stably exist and diminish in the patina layer as the corrosion develops.