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. 99 eV for the activation energy and D-0 = 39. 2 cm2 s-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. (authors)