チタン薄膜と水素・酸素の反応カイネティクス

抄録

Thin oxide layers are formed on metal surfaces at ambient temperatures even at low oxygen residual gas pressures in vacuum systems or in inert gas atmospheres. Such oxide layers impede or prevent hydrogen absorption at ambient temperatures. To gain a fundamental understanding of the reaction mechanisms, reaction kinetics of hydrogen and oxygen absorption by titanium films were measured by using the Wagener volumetric method. Theoretical approaches to explain the effects observed are discussed. At the initial stage of the oxidation, ion transport by the Mott potential produced by electron tunneling controls the reaction probability. The pressure dependence of the hydrogen absorption rate indicates that the rate determining step of the reaction is either the dissociation of hydrogen molecules on the surface or the permeation or diffusion of hydrogen atoms in the film.