X-ray and Equilibrium Hydrogen Pressure Studies

There seems some underlying technological interest in recent developments (1-9) in palladium alloy systems because of the possibilities of developing palladium alloys with improved characteristics for use as diffusion membranes for hydrogen purification and allied purposes (10). In addition to the important issues of surface kinetics and membrane thickness, other key factors for improved diffusion characteristics are those of a decreased susceptibility to deformation during the course of hydrogen absorption and desorption cycles, combined with a retention of satisfactorily high rates of hydrogen permeation under particular conditions of temperature and hydrogen pressure gradients across the membranes. The permeation rate is governed by internal hydrogen concentration gradients as reflected by the corresponding p-c(n)-T relationships between equilibrium hydrogen pressure, p, hydrogen content, c (expressed as the ratio H:M of hydrogen to metal atoms and generally represented by n), and temperature, T.