Diffusion of oxygen in nickel: A variable charge molecular dynamics study

Variable charge molecular dynamics have been performed to study the diffusion mechanisms of oxygen atoms (O) in nickel (Ni) in the temperature range 950 K–1600 K. It is observed that oxygen does not diffuse via jumps of oxygen through interstitial sites but via a vacancy diffusion mechanism. The oxygen diffusivity can be well described by an Arrhenius law over the temperature range considered. The oxygen diffusion coefficient has been analysed and indicates a value of Ea=1.99eV for the activation energy and D0=39.2cm2s−1 for the pre-exponential factor. Our numerical results were compared with a compilation of experimental and theoretical studies, and exhibit a good agreement with the previous approaches.