An experimental investigation of the diffusion of electrolytic hydrogen through metals

Abstract

Experiments have been made to test whether hydrogen produced electrolytically on one side of a metal plate will diffuse through the plate. The Shakespear katharometer was used to detect and measure the diffused gas. The metals examined were iron, nickel, cobalt, copper, zinc, silver, palladium, platinum, and lead. Only in the case of iron and palladium was any diffusion observed. Measurements were made with iron showing how the amount of diffused gas varied with time, and how the rate of steady diffusion varied with the thickness of the plate. The variation of the rate of diffusion with the electrolysing current density was observed for plates of iron and palladium. The results agree well with those of other observers for large values of the current density, but show that a threshold value of current density does not exist and that for low values of current density the rate of diffusion is approximately proportional to it. The diffused gas appears to be in the ordinary molecular state. A simple theory which explains the general character of the experimental results is given.