Numerical simulation of hydrogen atom transport in thick nickel membrane using semi-empirical quantum model

The transport characteristics of hydrogen atoms are of significant interest within the energy industry. In this study, molecular dynamics (MD) simulations based on a semi-empirical quantum model are performed to examine the diffusion of hydrogen in a dense nickel membrane. The mean square displacement (MSD) and diffusion coefficients of the nickel and hydrogen atoms are derived at various temperatures in the range of 300–1800 K. The numerical results reveal the changes which take place in the transportation mechanism of the hydrogen atoms as a result of a temperature-induced variation in the lattice structure. It is shown that the transport of the hydrogen atoms changes from an interstitial diffusion mechanism at temperatures lower than 1200 K to a vacancy diffusion mechanism at temperatures of 1600–1800 K as result of a change in the nickel lattice from an ordered FCC structure to an amorphous-type structure.