Thermodynamic Evaluation of the Ga–Y System

The thermodynamic modeling of the gallium–yttrium binary system was carried out with the help of the CALPHAD (CALculation of PHAse Diagram) method. Ga 2 Y, GaY, and the three polytypes Ga 3 Y 5 have been treated as stoichiometric compounds while a solution model has been used for the description of the liquid phase and the (Ga) and (Y) solid solutions. The excess term of the Gibbs energy of the solution phases was assessed with the recent exponential temperature dependence of the interaction energies by Kaptay (Calphad 28–2:115–24, 1 ; Calphad 32–2:338–52, 2 ; Mat Sci Eng A 495:19–26, 3 ) and compared with the Redlich–Kister (Ind Eng Chem. 4 ;40:345) polynomial equation results. The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values available in the literature.