Equilibria in the Niobium-Hydrogen System

Equilibria in the niobium‐hydrogen system were determined in the range 100°–900°C, 10–1000 mm of mercury hydrogen pressure, and atomic ratios of hydrogen to niobium of 0.01–0.85. A single phase solid solution of hydrogen in niobium was produced throughout most of the system. In no region did the equilibrium solubility exactly follow a simple pressure dependency. The heat of solution increased with hydrogen content, which behavior may be related to an expansion in the niobium lattice.