The adsorption of two organic inhibitors on stainless steel passive film: A reactive force field study

Reactive molecular dynamics (MD) simulations were performed to investigate the adsorption of water and the organic corrosion inhibitors vitamin C (VC) and 2-vinylsuccinic acid (VSA) on Cr2O3 (001) surface. Adsorption of the inhibitors is accompanied by the formation of Cr-O covalent bonds and O…H hydrogen bonds. The superior corrosion inhibition performance of VC than VSA and their preferential parallel adsorption geometry can be attributed to more bonds to the surface. The adsorption of water on the Cr2O3 surface leads to the formation of a multilayered structure with a higher atomic intensity than bulk water in which the first two layers interact directly with the metal oxide surface. When an inhibitor layer and water are both present, the inhibitor effectively blocks Cr2O3-water interactions but water significantly weakens the inhibitor’s adsorption. These findings shed new light on the mechanism of corrosion inhibition in stainless steel.