HYDROGEN ABSORPTION IN PALLADIUM FILMS SENSED BY CHANGES IN THEIR RESISTIVITY

The resistance of pure palladium Films of 11, 30 and 54 nm thickness w as monitored during their exposure to H-2 at pressures ranging between 1 and 20 Torr. After completing a cycle of H-2 absorption/desorption, the resistivity changed in a ''saw tooth'' fashion similar to the cha nges observed in surface adsorption of hydrogen by other transition me tals. Large resistance changes are observed in these studies, confirmi ng that bulk hydrogen absorption occurs in Pd while hydrogen surface a dsorption becomes dominant over bulk absorption in other metals such a s niobium. The resistance change curves carry the information of the k inetics of absorption.