Thermodynamic Functions for the Tantalum-Hydrogen System

Abstract

Equilibria in the tantalum‐hydrogen system were determined in the range 300°–700°C, at hydrogen pressures of 10–1000 mm of Hg, and atomic fractions, , 0.05–0.333. A single‐phase solid solution of hydrogen in tantalum was produced throughout the experimental ranges. Obedience to Sieverts' law is approached at 500°C and higher for compositions below . The data were used to calculate the relative partial molar and total enthalpies, entropies, and free energies for formation of the solid solutions.