Corrosion kinetics and patina evolution of galvanized steel in a simulated coastal-industrial atmosphere. Issue 10 (October 2019) - Qiao, Chuang
Highlights: Galvanized steel shows stages of different corrosion kinetics and zinc patina features. Zn5 (OH)6 (CO3 )2 and Zn4 (OH)6 SO4 are the main stable composition in the patina layer. Zn12 (OH)15 Cl3 (SO4 )3 cannot stably exist and diminishes as the corrosion proceeds. Patina layer on galvanized steel plays a key role in atmospheric corrosion of galvanized steel. 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, Zn5 (OH)6 (CO3 )2 and Zn4 (OH)6 SO4 are identified as the main stable composition and exhibit an increasing relative amount; while Zn12 (OH)15 Cl3 (SO4 )3 cannot stably exist and diminish in the patina layer as the corrosion develops.