Molecular dynamics simulations of interaction and very first step oxidation in the surface of ferritic Fe-Cr alloy

Abstract

Abstract Ferritic Fe-Cr alloy is one of the most important metallic interconnect material for the solid oxide fuel cells (SOFCs). And its antioxidant performance is vital to the operation of SOFCs. Based on the ReaxFF reactive potential, the interactions between incident O ion and the (0\xa00\xa01) surface of ferritic Fe-Cr alloy are simulated by classical molecular dynamics. When the incident O ion collides with the surface, adsorption, reflection and sputtering of O ion are observed, and adsorption is the dominant interaction. The incident O ions are found to be adsorbed at tetrahedral interstitial positions between Fe and Cr atoms in the top Fe-Cr mixed layer and be adsorbed closely around Fe atoms in the deeper pure Fe layers when incident with different initial kinetic energies. And our results reveal that Fe-O compounds are easier to form with the increasing kinetic energy of incident O ion and increasing temperature. The oxidation behavior in the surface is analyzed and a proposal is finally provided for improving antioxidant performance of the Fe-Cr alloy applied in the solid oxide fuel cells.