Electrochemical corrosion behavior of S31254 stainless steel in simulated desulfurization flue gas condensates

Abstract

This study presents the first systematic investigation into the coupled effects of temperature, pH, and ion concentrations (Fe³⁺, Cl⁻, and NO₃⁻) on the electrochemical corrosion behavior of S31254 austenitic stainless steel in simulated flue gas condensate. Advanced electrochemical techniques—including potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Mott-Schottky analysis—were employed to evaluate corrosion performance under varying conditions. Results indicate that both elevated temperature and low pH significantly destabilize the passive film, thereby reducing corrosion resistance. At 60 °C, Fe³⁺ ions notably accelerate corrosion due to their strong oxidizing nature and influence on anodic polarization. In contrast, Cl⁻ and NO₃⁻ ions exhibit relatively minor effects under the tested conditions, which is unexpected given the commonly aggressive behavior of chloride ions. These results reveal complex environmental interactions influencing the passivation and corrosion behavior of stainless steel in flue gas environments. The findings offer valuable insights into the corrosion mechanisms occurring in flue gas desulfurization (FGD) systems and emphasize the need to consider synergistic environmental factors. This study contributes to the development of more effective corrosion mitigation strategies, thereby supporting the long-term durability and safe operation of exhaust gas treatment facilities.