Enthalpies of mixing of Au-Pb and Ag-Au-Pb liquid alloys at 973 K

The enthalpies of mixing of the gold-lead and silver-gold-lead alloys were determined at 973 K by using a high temperature Calvet calorimeter (400 K < T < 1400 K). The mixing enthalpies of Au-Pb liquid are negative over the entire composition range with a minimum Delta H-mix(m) = -1074 J mo(-1) at X-Au = 0.40. The enthalpies of formation of ternary liquid alloys have been carried out along the following sections: X-Ag/X-pb = 1/4, X-Au/X-pb = 1/4 and 2/3 at 973 K. Experimental values of Delta H-mix(m) =f(X-Ag, X-Au) are compared with those predicted from the Kohler, Muggianu and Toop relations. An assessment including the excess ternary parameter is presented. (c) 2007 Published by Elsevier B.V.