LAUSR

In this study, the passivity and pitting corrosion of 316L in simulated concrete pore solutions were investigated through polarization curve, electrochemical impedance spectroscopy (EIS), and Mott– Schottky (M-S) analyses. In solutions with different pH levels and Cl − concentrations, the corrosion resistance of 316L decreases with decreasing pH and increasing Cl − concentration. The breakdown potential (Eb) is linearly related to the logarithm of Cl − concentration under weak alkaline solutions. The undissolved corrosion product outflow from the corrosion pit would damage the passive film covered by the precipitates. In EIS results, the passive film resistance of 316L in pH 13 is higher than those in pH 9 and 11. In the XPS spectra, the ratios of Cr/(Fe+Cr+Ni) and Fe 3+ / Fe 2+ increase because of the selective dissolution effect on solutions with high Cl − concentration and pH. In M-S data, the passive films under all test solutions are identified as n-type semiconductor. Concrete carbonation and Cl − enrichment can reduce the stability of passive films and increase the corrosion tendency in marine environments.