Novel instrument and method for the investigation of small permeation fluxes of gases through different membranes

In order to provide a glimpse of the possibilities of the new equipment, hydrogen permeation measurements through a low-density polyethylene (LDPE) and a nickel membrane are presented. The pressure difference dependence of the hydrogen fluxes measured agreed well with the behaviour expected according to Sieverts' law. In case of the LDPE membrane our results can be explained with the molecular diffusion of hydrogen, which agrees with literature data. As for the nickel membrane the results suggest that under our experimental conditions the speed determining step of the permeation is the atomic diffusion.