Unveiling the influential mechanism of O2 on the corrosion of N80 carbon steel under dynamic supercritical CO2 conditions

The influential mechanism of O2 on the corrosion of N80 carbon steel under dynamic supercritical CO2 conditions was explored by mass loss and electrochemical tests, and surface analysis. It is demonstrated that the introduction of O2 inhibits the corrosion of steel. The developed water chemistry model confirms that the decrease in the corrosive species concentration by introducing O2 is not responsible for the inhibition to steel corrosion. The corrosion inhibition of O2 is implemented by promoting the formation of protective FeCO3 film in the initial period owing to the diffusion barrier effect of the formed outer ferric hydroxide/oxide film.