The sorption of hydrogen and deuterium by copper and palladium II-The sorption by palladium and diffusion through copper

In Part I it was shown that the process of activated diffusion of hydrogen into copper was composite including a true activated diffusion; the energy of activation for the hydrogen and deuterium migration differing from one another to an extent which was slightly less than the zero point energy differences of tire compound CuH and CuD. In addition another reaction independent of the nature of the two gases was found to be present and which governed the reaction velocity at low temperatures. In order to discover whether this second reaction was localized at the gas solid interface or not, methods had to be devised for observing the diffusion of hydrogen through thin copper films. Copper films formed by electroplating on stainless steel and stripping off by razor blades proved too fragile to Use without support, and finally deposition on palladium as support was adopted. This necessitated a series of investigations on the behaviour of palladium in respect to its permeability for the two isotopes and an examination as to how far a palladium copper interface differed from a gas copper interface in respect to diffusion. Solution and Diffusion in Palladium The palladium was employed in two forms, a thin palladium tube and a palladium disc of approximately the same area and thickness as the tube.