A THERMODYNAMIC INVESTIGATION OF LIQUID GOLD-ANTIMONY ALLOYS

The enthalpies of mixing of liquid Au-Sb alloys were determined betwee n 906 and 1028 K giving Delta(mix) h(m)(o) = x(Sb) x(Au) (-11.234 - 1. 1078x(Sb) + 5.713x(Sb)(2)) kJ mol(-1). The minimum was found at x(Sb) = 0.45 with Delta(mix) H-m(o) = -2.62 +/- 0.2 kJ mol(-1) contrary to p ublished measurements on liquid Au-Sb alloys. The limiting partial mol ar enthalpy of Au in Sb at 935 K was measured to Delta(mix) h(m)(o)(Au , liq, in infinity Sb, liq)= -6.05 +/- 0.4 kJ mol(-1). The enthalpy of formation of the solid compound AuSb2 determined at 298 K by solution calorimetry in liquid Sb, Delta(f)H(m)(o)(AuSb2) = -5.40 +/- 0.6 kJ m ol(-1), is found in fair agreement with literature data. DTA measureme nts were performed on the Au-rich part of the liquidus and a new liqui dus curve is suggested between Au and the eutectic concentration. The eutectic point was found at 630.37 +/- 0.25 K and x(Sb) = 0.350.