Hydride stability for palladium and palladium based fcc alloys

The thermodynamic properties of palladium and palladium based fcc alloys-hydrogen systems have been extensively studied. It is well known that there is a good correlation between hydride stability and cell volume for palladium based fcc alloys. In this research, the dominant factor for the hydride stability was discussed in terms of the conventional thermodynamics. Calculated chemical potential of hydrogen was analytically separated into the infinite dilute solution of hydrogen and the excess chemical potential of hydrogen. There was a sufficiently good correlation between the chemical potential of infinite dilute solution of hydrogen and the hydride stability of palladium based fcc alloys. On the other hand, the correlation was poor between the excess chemical potential of hydrogen and the hydride stability. These results led to the conclusion that the plateau pressure of palladium based fcc alloys was dominantly controlled by the chemical potential of infinite dilute solution of hydrogen.