It was recalled that H-metal reactions at 3 to 5GPa could lead to H-induced lattice migration. The occurrence of fast diffusion within the metal lattice was established. Under these conditions, modification of the diffusion kinetics and phase equilibria permitted the production of vacancy-ordered phases having vacancy concentrations of the order of 20%. An alternative route was presented which led to such phases which were stable at normal pressure and temperature. In the case of Pd, the vacancy-ordered state was characterized by the loss of superconductivity with respect to the Pd hydride. This marked modification of the physical properties was explained in terms of band-structure calculations for various types of decorated vacancy having an octahedral coordination.

Investigation of the Vacancy-Ordered Phases in the Pd-H System. S.Miraglia, D.Fruchart, E.K.Hlil, S.S.M.Tavares, D.Dos Santos: Journal of Alloys and Compounds, 2001, 317-318, 77-82