Calorimetric investigation of Al-Zn alloys using Oelsen method

Abstract

The results of calorimetric study of binary Al-Zn system done according to the Oelsen thermodynamic method are presented in this paper. Main thermodynamic properties, including activities, activity coefficients, partial/integral molar Gibbs excess, and mixing energies were determined at 1,000 K. Positive deviation from Raoult law was noticed, with minimal values of Delta G (M) about -3 kJ mol(-1) and maximal values of Delta G (E) about +2 kJ mol(-1). The energetics of mixing in liquid Al-Zn alloys has been analyzed through the study of concentration fluctuation in the long-wavelength limit, and weak affinity between Al and Zn atoms in the system was observed. Differential thermal analysis and light optic microscopy were applied in the frame of characterization of investigated binary alloys and phase diagram examination, and the results obtained were in accordance with available literature data.