Evaluation of the Pitting Corrosion of Modified Martensitic Stainless Steel in CO2 Environment Using Point Defect Model

Pitting corrosion is a significant concern for the broader application of stainless steel in modern industries which metal and alloy are detached preferentially from susceptible parts on surface, resulting creation holes passivated alloys that exposed to an aqueous, neutral electrolyte containing corrosive species. Exposure SS brines leads localized loss surface passivity onset isolated pitting, render equipment or piping unfit service. In present study, passive layer behavior pitting modified martensitic (MMSS) were evaluated saturated CO2 environment (pH~5) with different NaCl concentrations temperatures, using various electrochemical techniques. It was found by increasing temperature up 60 °C, resistance MMSS increased; however, rate dramatically increased at 80 indicating destruction oxide layer. According point defect model (PDM) results, calculated values polarizability (?), cation diffusivity (D), annihilation vacancies (jm), reveal strong dependence solution temperature.