Kinetics of hydrogen uptake for getter materials

Abstract

This paper studies the kinetics of hydrogen absorption for a non-evaporable getter material, and presents a basic gettering model. Hydrogen uptake takes three processes in this model: molecular dissociated chemisorption on the surface, atomic penetration from the surface to the bulk, and diffusion in the body. For low hydrogen bulk concentration a lattice-gas model is adopted to describe the diffusion behaviour of hydrogen in the bulk. The exact analytical solutions are given for the pumping hydrogen by solving rate equations of these three processes simultaneously. The influences of some factors on the hydrogen absorption rate are also discussed. The theoretical calculations are in good agreement with the experiments performed with a Zr–Al (16%) getter and a Zr film on the Mo substrate.