Measurement of thermodynamic properties of Al-Sb system by calorimeters

The free energy, heat and entropy of mixing in a liquid Al-Sb alloy were derived by combining heat contents of the alloy with the heat and entropy of formation of the equiatomic compound of AlSb at a reference temperature. The heat contents of the alloy were measured using a drop calorimeter in a temperature range from 800 to 1450 K and in a concentration range of N_Sb from 0.05 to 0.95. The heat and entropy of formation of AlSb were determined respectively from the heat of solution measurements at 773 K using a twin solution calorimeter and from the heat capacity measurements in a temperature range from 4 to 300 K using an adiabatic calorimeter. The obtained thermodynamic and phase diagram data for the Al-Sb system were analyzed using a Redlich-Kister polynomial equation and the optimized parameters were derived as a function of alloy composition and temperature.