An electrochemical investigation on the effect of the chloride content on CO ₂ corrosion of API-X100 steel

This research argues that the corrosion rate for high strength steel in CO ₂-saturated solutions reaches a maximum at a threshold chloride content. At 20°C, the corrosion rates increased from 60μA/cm ² in 5g/L solutions to a maximum of 185μA/cm ² in 15g/L solutions, and then became less in the more concentrated solutions. The anodic dissolution accelerated at 90°C and the cathodic reactions decelerated with adding 10vol.% oil where the chloride content effect remained relatively the same. Some EIS experiments demonstrated an agreement with the polarization results without confirming that threshold effect of chloride on charge transfer.