Experimental studies and thermodynamic assessment of the Ba-Mo-O system by the CALPHAD method

Thermodynamic measurements on BaMoO4, BaMoO3 and BaMo3O10 are reported, that served as input for the development of a thermodynamic model Ba-Mo-O system using CALPHAD methodology. The valence states molybdenum in BaMoO4 were confirmed to be VI IV, respectively, from X-ray Absorption Near Edge Structure Spectroscopy at Mo K-edge. heat capacity low temperatures these compounds was obtained thermal-relaxation calorimetry. Phase equilibrium data BaMoO4-MoO3 section also measured, transition enthalpy associated with peritectic decomposition determined Differential Scanning Calorimetry. developed used compound energy formalism intermediate compounds, an ionic two-sublattice liquid phase. optimized Gibbs energies assessed respect known phase data. A good agreement is generally obtained, but number ill-defined identified.