Molecular Origin of the CO2-Enhanced Water Wetting During Corrosion of an Oil Layer-Attached Steel Surface in Water Flows

To understand the role of CO2 in multiphase flow corrosion, the durability of an oil layer attached to a steel surface against fluid flows was systematically evaluated. It confirms that CO2 can destabilize the protective oil layer and initiate electrochemical corrosion through the oil layer, showing a solution chemistry governed flow dependency. The CO2-induced oil layer rupture was attributed to the water droplet actions at the oil/water interface and the steel surface, where the generation of microdroplets was facilitated by the interactions between the dissolved CO2 and the oil molecules. It gives new insights into the replacement of oil layer by water in CO2-containing multiphase fluids, which benefits many application fields, such as corrosion and lubrication in oil-water mixed environments.