Solution of hydrogen in thin palladium films

Abstract

Solubility enhancements have been observed for hydrogen in thin Pd films (250–820 Å) in the αphase. Thermodynamic data for the films are determined from isotherms at temperatures between 25 and –40 °C and are compared with those for bulk Pd. From the values of W_H—H(interaction energy of hydrogen in the film) and the solvus behaviour, it is suggested that the hydride phase in the films is destabilized relative to the dilute phase as the film thickness decreases. The dependence of the solubility on annealing has been examined for a thin film. The results indicate that the special characteristics of thin films disappear after annealing at ca. 400 °C.