First-principles study of surface orientation dependent corrosion of BCC iron

Using inputs from first-principles calculations, an ab initio model was employed to investigate crystal orientation dependent corrosion behavior of BCC iron. Results showed that the sequence of corrosion susceptibility of BCC Fe surfaces is in the order of (100) > (111) > (211) > (310) > (110). The higher corrosion current on (100) surface suggests that cathodic hydrogen evolution may largely determine the corrosion reactions under acidic environment. The predicted corrosion potential and current for lower index planes are in general agreement with available experiment. The model was further applied to study alloying effects with results validated via weight loss analysis of alloyant fabricated by arc melting.