On the mechanism of carbon dioxide corrosion of mild steel: Experimental investigation and mathematical modeling at elevated pressures and non-ideal solutions

摘要

The mechanistic study of uniform CO2 corrosion in the pH range from 4 to 6 and CO2 partial pressures up to 15 bar showed that neither H2CO3 nor HCO3- were reduced directly during the corrosion process to any appreciable extent. The significant effect of these carbonate species on the corrosion process is through their homogeneous dissociation insider the boundary layer. This mechanistic view was further quantitatively verified using a comprehensive mathematical model, developed with hydrogen ion reduction as the sole cathodic reaction while accounting for the effect of homogeneous chemical reactions, turbulent flow mixing, and non-ideal solution properties.