Corrosion behaviors of iron in a supercritical CO2 environment: a molecular dynamics study

Corrosion caused by supercritical CO2 can cause serious damage to equipment. This study investigates the corrosion behaviors of iron in supercritical CO2 by molecular dynamics simulations via considering the effect of different factors including temperatures (T), the density of CO2 (rho(CO2)) and surface roughness of iron (lambda(p)). It is found that the corrosion process includes three stages. The first stage is dominated by CO2 diffusion. Rapid corrosion happens in the second stage, with a high reaction rate and plenty of corrosion products generated. In the third stage, these products prevent the reaction from proceeding and the system becomes stable. Moreover, it is demonstrated that the corrosion reaction is highly activated with T > 700 K. The rho(CO2) has little effect on the corrosion rate, leading to the maximum reaction rates with different rho(CO2) almost identical. The lambda(p) hardly affects the degree of corrosion but can accelerate the corrosion progress. [Graphics] .