Thermodynamic functions and phase diagrams of tantalum + hydrogen and tantalum + deuterium systems

Abstract

Ultra-high vacuum techniques have been applied to investigate the solubilities of hydrogen and deuterium in tantalum. Measurements of equilibrium pressure and electrical resistance have been used to outline the phase diagram, to investigate the isotope effect and to determine the variation of thermodynamic properties with composition. All experimental measurements were taken in (pressure, composition, temperature) ranges of 10^–8 to 10^–1 Torr (1 Torr = 133.32 N m^–2), 0.0036 to 0.78 ( H or D )/Ta atomic ratio and –78 to 240°C respectively.