Thermodynamics and thermophysical properties of liquid Au-Ge alloys

The mixing behaviour of liquid Au-Ge alloy system has been investigated by the Quasi-Chemical Approximation (QCA) in the frame of the Quasi-Lattice Theory (QLT) combined with a statistical mechanical theory. Assuming the order energy parameters as temperature dependent, various thermodynamic quantities are calculated at different temperatures using the QCA for regular solution and the subregular solution model. Thermodynamic properties of this system deviate negatively from the Raoult's law, while the thermophysical properties exhibit an opposite trend, typical for compound forming systems. The energetics of mixing in liquid alloys has been analysed through the study of surface properties (surface tension and surface composition), transport properties (diffusion, viscosity, el. resistivity) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter). Theoretical results are in agreement with the corresponding literature data and support a compound forming tendency in liquid Au-Ge alloys.