Enthalpies of Formation at 1373 K of the Liquid Alloys Ag + Au, Ag + Sn, Au + Sn and Ag + Au + Sn

Abstract

Abstract The enthalpies of formation Δ H M of the liquid binary (Ag + Au, Ag + Sn and Au + Sn) and ternary alloys (Ag + Au + Sn) were measured at 1373 K by direct calorimetry on the whole concentration range. The ternary investigations were conducted along the sections X Ag / X Au = 1/4, 1/1, 6.25/3.75 and 7/3 with X Sn < 0.60 and X Ag / X Sn = 3/7, 1/1 and 7/3 with X Au < 0.60. The apparatus used was a very high temperature calorimeter with a sensing device consisting in 20 Pt + 6% Rh/Pt + 30% Rh thermocouples. The experimental uncertainty was quoted at 10%. The results obtained for the limiting binary systems were compared with those, numerous and contradictory, reported in literature. The enthalpies of formation of the ternary alloys Ag + Au + Sn can be represented using a modified Kohler's equation including a supplementary correction term to the binary contributions.