Computer calculation of the 700 K isothermal section of the Ba - Mo - O system from thermodynamic data

The phase diagram for the Ba-Mo-O system has been calculated by the use of the SOLGASMIX-PV program, which computes equilibrium composition by minimisation of the Gibbs energy of the system. Unit activity is assumed for the condensed phases for the calculation of the phase diagram. Gibbs energies of formation of various possible binary and ternary compounds present in the system are the primary input for the program. For the elements and binary compounds the thermodynamic and phase equilibria data available in the literature were used. For all ternary compounds, the Δ f G m o (T) values used (where Δ f G m o is the Gibbs energy of formation and T is temperature) were either experimentally determined or estimated by the present authors. Oxygen potentials over the various coexisting phase fields have been calculated. The present study gives the phase diagram for the Ba-Mo-O system for the first time.