Sodium Chloride Concentration Effects on General CO₂ Corrosion Mechanisms

The general carbon dioxide (CO₂) corrosion rates of C1018 (UNS G10180) carbon steel have been measured for sodium chloride (NaCl) concentrations 3 wt% to 25 wt% at 20°C, pH 4.0, 5.0, and 6.0. Experimental results showed that high salt concentrations decreased the general CO₂ corrosion rate significantly and nonlinearly. Potentiodynamic sweep analysis shows that both cathodic and anodic processes were retarded. Flow velocity effects on general CO₂ corrosion rate were minimized as a result of an increase of salt concentration. No effect of high salt concentration on initiation of localized attack was detected.