Effect of Cl− on the Properties of the Passive Films Formed on 316L Stainless Steel in Acidic Solution

The corrosion behavior of 316L stainless steel (316L SS) has been investigated in solutions containing various concentrations of chloride ions by using potentiodynamic polarization, capacitance measurement and Mott-Schottky relationship analysis (M-S). The result indicates that passive currents change slightly with the addition of chloride ions. The pitting potential (Epit) decreases linearly with log[Cl−]. Correspondingly, the point defect diffusion coefficient (Do) of the passive film increases linearly with increasing log[Cl−]. The results also indicate that the pitting corrosion of 316L SS follows the adsorption mechanism in NaCl solution.