Experimental and Calculated Ag + Au + Ge Phase Diagram

The investigation of the equilibrium phase diagram of the Ag + Au + Ge system has been carried out by the following ways: (a) the location of equilibrium surfaces was determined on the whole composition range by high temperature isoperibolic calorimetry and differential thermal analysis; (b) the equilibrium temperatures of the ternary system were calculated from the equilibrium temperatures and the thermodynamic functions referring to the three limiting binary alloys Ag + Au, Ag + Ge, Au + Ge. A satisfactory agreement was found between the calculated liquidus and the one obtained by calorimetry and thermal analysis. In the course of a systematic thermodynamic investigation of ternary alloys based on gold, silver, and a IV b metal, the three systems Ag + Au + Si, Ag + Au + Ge, and Ag + Au + Sn were examined; the molar enthalpies of formation of the liquid mixtures were obtained on the one hand and the equilibrium phase diagrams on the other.^1,2,3 This paper focuses on the latter topics for the ternary alloys Ag + Au + Ge; a comparison is carried out between the equilibrium temperatures measured by differential thermal analysis at the laboratory S.E.T.T. in Marseille and those calculated at the Royal Institute of Technology in Stockholm. This calculation is based on the thermodynamic data published for the limiting binary systems and also on the ternary enthalpies measured by calorimetry at very high temperature.