Pitting Corrosion Behavior of Stainless Steel 304 in Carbon Dioxide Environments

The pitting corrosion behavior of stainless steel (SS) 304 in aqueous CO 2-H 2S-Cl- environment was investigated by potentiodynamic cyclic anodic polarization and electron probe microanalysis (EPMA). The experimental results show that the pitting corrosion susceptivity of SS 304 increases with the increase of temperature. Chlorine ion is the prerequisite for pitting corrosion of SS 304 in H 2S-CO 2 environments. There is a linear relationship between the pitting corrosion potential (E b-100) and chlorine ion concentration, and E b-100 becomes noble with increasing pH value of the solution with or without H 2S. pH value has little effect on the protection potential with the presence of H 2S. H 2S increases strongly the pitting corrosion susceptivity and deteriorates the pitting corrosion resistance of SS 304 in CO 2 environments. The observations by EPMA show that SS 304 in CO 2-saturated NaCl solution (3 %) with H 2S suffers pitting corrosion accompanied with intergranular corrosion.