A high-temperature thermodynamic investigation of the nb-mo system

Abstract

The thermodynamic properties of solid Nb(Cb)-Mo alloys have been determined between 1050 and 1300 K using solid state galvanic cells with a thoria-based electrolyte. The activities of niobium and molybdenum exhibit negative deviations from Raoult’s law. The excess entropies of mixing are very small and negative, and the excess integral free energies of mixing are almost equal to the integral enthalpies of mixing. The negative entropies of mixing are attributed to a negative vibrational contribution and/or short-range ordering.