Atomic-scale wear behaviors of iron oxide through the atom-by-atom attrition and plastic deformation of nano-asperities

Abstract

Atomic-scale wear, behaving distinctly from macroscale wear, has been gaining significant scientific interest. We previously proposed a semi-empirical wear model for covalent bonding materials, which primarily describes an interfacial-bond-dominant atomic-scale wear process. To assess the model's broader applicability on other material types, herein we selected the iron oxide (Fe2O3) as a representative ionic bonding material and conducted the large-scale atomistic simulations. The simulations unveiled two main atomic-scale wear mechanisms of Fe2O3: plastic deformation/cracking of nano-asperities induced by the asperity collision, and atom-by-atom attrition caused by the interfacial O–Fe bond formation. Crucially, our simulations proved effective in capturing the atom-by-atom attrition wear, thus confirming its validity for ionic materials and expanding its potential usefulness to a broader range of materials.