Calculation of phase equilibria and thermodynamic properties of the Li-Na-H system

Available data for the phase diagram and equilibrium hydrogen pressures in the Na-NaH system were optimized to obtain equations for the Gibbs energies of the phases as functions of composition and temperature. Phase diagram data for the Li-Na system were similarly optimized. For the Li-LiH system, optimized Gibbs energy expressions were taken from the literature. The Gibbs energy of ternary liquid Li-Na-H solutions were calculated from these optimized binary Gibbs energies by means of a sublattice model in which the system is treated as a reciprocal ternary system Li-Na-LiH-NaH. Calculated equilibrium hydrogen pressures in the ternary system agree well with available data. Several calculated isothermal sections of the ternary phase diagram are presented. (orig.)