Corrosion Behavior of Galvanized Steel in Dongguan Atmosphere and Simulated Atmosphere

The corrosion behavior of galvanized steel in Dongguan atmospheric environment and simulated atmospheric environment was studied by weight-loss method, metalloscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and electrochemical impedance spectroscopy (EIS). The results show that localized corrosion occurred in the early exposure in Dongguan atmosphere. With the extension of exposure time, the corrosion rate of galvanized steel firstly decreased rapidly and then gradually stabilized. At the same time, the corrosion resistance of galvanized steel firstly decreased and then increased. The main corrosion products of galvanized steel were ZnO and Zn₄SO₄(OH)₆ after being exposed in Dongguan atmosphere for 12 months. In the simulated atmospheric environment, the trend of corrosion rate and corrosion resistance of galvanized steel with time had good correlation with the results of field exposure test in Dongguan.