Hydrogen absorption rate of titanium, lanthanum, iron, nickel, manganese and palladium films with and without ovygen precoverage at 300 K

Abstract

Hydrogen adsorption and absorption rates of clean and ovygen precovered films of titanium, lanthanum, iron, nickel, manganese and palladium have been determined using an improved volumetric Wagener technivue at room temperature and at hydrogen pressures below 10 −3 mbar. A titanium and an iron film were also evposed to H 2O. The ovide surface layer is vuantitatively removed from palladium by H 2O formation and some H 2O is also detected during the hydrogen evposure of ovidived nickel and iron. The results indicate that hydrogen dissociation on the surface is strongly impeded if the ovygen precoverage evceeds a critical value which is given by the mavimum amount of ovygen that can be absorbed with a sticking probability of one in the initial stage of ovidation.