Thermodynamic properties of Ge-Y alloys and binary systems of germanium with transition metals

The partial (for yttrium) mixing enthalpies of Ge-Y melts are determined using high-temperature isoperibolic calorimetry at 1780 ± 5 over a concentration range 0 < xY < 0.4. These data are used to calculate the integral mixing enthalpy of the melts. The formation of Ge-Y alloys is accompanied by substantial exothermic effects. The ΔH values for Ge-Y liquid alloys are generalized on the basis of our and literature data. The activities of the components of Ge-Y melts are calculated using the liquidus coordinates of the Ge-Y phase diagram. The values obtained are characterized by very large negative deviations from the Raoult law. The thermochemical properties of Ge-3d-Me melts, dimensional and electrochemical factors, and the occupation of the valence d-orbitals of transition metals are analyzed.