Early stage oxidation of Ni-Cr binary alloy (111), (110) and (100) surfaces: A combined density functional and quantum chemical molecular dynamics study

First-principles and tight-binding quantum chemical molecular dynamics were used in this study. The chemisorption energies of O and OH on the Ni-Cr (1. 1. 0) surface are lower than those of other surfaces. The oxygen 2p orbitals hybridise with Ni 3d, 4s and small amounts of p orbitals for the (1. 0. 0) surface while Ni p orbitals have no contribution for the (1. 1. 0) surface, which might reduce the adsorption energy. Additionally, oxygen acquires the maximum depth into the Ni-Cr (1. 1. 0) surface. Applied strain increases the oxygen diffusivity. This study reveals that the Ni-Cr (1. 1. 0) surface is easier for oxygen diffusion accordingly oxidation accelerates.