A Calorimetric Study of Alloy Formation in Au-Cu and Au-In Systems

A calorimetric study of alloy formation in Au-Cu and Au-In systems was carried out. The heats of mixing, ΔH _mix, were measured at 1380,1484 and 1604 K for Au-Cu and at 1387, 1449 and 1505 K for Au-In in the full concentration range. The results of experiments were described by approximating equations. Observed values of ΔH _mix were discussed using the phase diagrams of the systems. It was shown that the systems become closer to the ideal state with increasing temperature. From the experimental data, the dependencies of the enthalpies of the systems on the composition and temperature were estimated. The simultaneous effects of composition and temperature on enthalpy are represented in 3D diagrams. The specific heats of the alloys, in the temperature range of experiments, were derived from the slopes of enthalpy planes. This revised version was published online in August 2006 with corrections to the Cover Date.