Pitting corrosion of 316L stainless steel under low stress below yield strength

Pitting corrosion of 316L stainless steel (316L SS) under various stress was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) analysis in 3.5% NaCl solution. The results of polarization curves show that, with the increase of the stress, the pitting potentials and the passive current density markedly decrease firstly (180 MPa), and then increase greatly (200 MPa). The corresponding surface morphologies of the samples after the polarization test well correspond to the results. Mott-Schottky analysis proved the least Cl ^- adsorbed to the surface of passive film with more positive flat potential, indicating that a moderate stress could increase the pitting corrosion resistance of 316L SS in 3.5% NaCl solution.