Kinetics of Hydrogen Absorption, Desorption And Permeation of Metals

The reaction mechanisms for the absorption of hydrogen by metals from moist hydrogen gas and dilute acid solutions, for the desorption from metals of dissolved hydrogen in the presence of water and for hydrogen solubility and permeation under those conditions are discussed. Their kinetics are also given. Formulae are derived for rates and equilibria. These are compared with experimental data. The migration of H atoms in the metal is concluded to be associated with zero or nearly zero activation energy. Diffusion is rapid enough to maintain almost uniform distribution of H atoms in the metal during absorption and desorption under ordinary conditions. 3.8.4