High-temperature diffusion of hydrogen and deuterium in palladium

Abstract

The diffusivity of hydrogen and deuterium in palladium has been measured at temperatures between 773 and 1373 K and at hydrogen and deuterium concentrations less than 10^–4 H/Pd and D/Pd (atomic ratio). The measured diffusion coefficients for hydrogen (D_H) and deuterium (D_D) showed Arrhenius behaviour. The dependence of the ratio D_DD_H on temperature has been explained by a model of diffusion in which a hydrogen atom in an octahedral site of the palladium lattice can jump into the adjacent octahedral site only when local deformation of the palladium lattice assists the jump.