THERMODYNAMIC PROPERTIES OF LIQUID AL-NI AND AL-SI SYSTEMS

Thermodynamic properties of Liquid Al-Ni and Al-Si alloys have been investigated at 1100 K by using galvanic cells denoted by Al(1) vertical AlCl//3 in NaCl. KCl(1) vertical Al-Ni or Al-Si(1). The activity coefficients gamma prime //A//l and gamma double prime //A//l of aluminum in Al-Ni and Al-Si, respectively, have been fitted to ln gamma prime //A//l equals minus (2612/T) X//N//i**2 and ln gamma //A//l double prime equals minus (2090/T) X//S//i**2 where T is temperature in K, and X//N//i and X//S//i are the mole fractions of Ni and Si. The equations corresponding to the activity coefficients of Ni and Si have been obtained by interchanging the subscripts since the equations for each system are symmetric as required by the regular solution theory. The results have been compared with other investigations, particularly with those obtained by calorimetry and by gas-condensed phase equilibria.