Limiting role of desorption in hydrogen transport across a deposited beryllium film

Hydrogen transport across a deposited beryllium layer has been investigated using the hydrogen permeability and concentration pulse methods. A layer of beryllium was deposited on a prepurified nickel membrane by cathode sputtering in a glow discharge plasma in “especially pure” grade hydrogen. An analysis of the experimental results showed that the main limiting process for hydrogen transport is desorption from the layer rather than diffusion in the bulk of the layer. A mathematical transport model is proposed and used to determine the rate constant of hydrogen desorption from beryllium.