Atomic Investigation of Corrosion Mechanism and Surface Degradation of Fe–Cr–Ni Alloy in Presence of Water: Advance Reactive Molecular Dynamics Simulation

Abstract

Steel is the most versatile engineering and construction material. Construction, power, automobiles, infrastructure, manufacturing and various different industrial sectors are using steel as their most important raw material. It is also the most recycled metal material on earth. But steel is having a major problem of rusting when exposed to water. Interaction of steel products with water is almost unavoidable in majority of the cases like automobiles, construction, water pipes, etc. Thus a detailed atomistic study of steel with water is required to understand the corrosion behaviour. At the atomic scale, Fe, Cr, and Ni are the major alloying elements of steel and highly reactive with water which results in corrosion and degradation of both surface and bulk properties. Therefore, we have used reactive molecular dynamics simulation (RMDS) to investigate reactivity of water with Fe–Cr–Ni substrate. We have carried out large number of simulations at different initial conditions and found that water molecules split into H and OH. Further, OH predominantly reacts with Cr and forms chromium oxide compounds over the Fe–Cr–Ni substrate. In the next step, variation in potential energy and mean square displacement have been used for quantitative characterization of reaction between water and Fe–Cr–Ni substrate. This study can provide detailed perspective towards the corrosion behaviour of steel in humid environment.