Diffusion coefficients of deuterium in palladium deuteride during ab- and desorption in high pressures of gaseous deuterium at 298 K

Exerting pressure jumps of several kbar in gaseous deuterium in the range of 5-28 kbar, surrounding a palladium deuteride wire, the diffusion coefficients of deuterium in the solid phase were evaluated by following the time course of the electrical resistance. Absorption of deuterium is characterized by a smaller diffusion coefficient than its desorption. Both represent a decreasing function with the increase of deuterium pressure. The difference of the ab- and desorption kinetics is explained by the influence of the elastic energy on the energetics of the occupation of metallic interstitials by deuterium particles. Comparisons with previous measurements are given. (author)