Enthalpy of formation of Au–Sn intermetallic phases. Part II

The technique of solution calorimetry with liquid Sn has been used for the determination of enthalpy of formation of intermetallic compounds from the Au–Sn system. The intermetallic phases were prepared and homogenized in a glow-box operated in high purity argon. They were analyzed by an X-ray diffraction method before the calorimetric investigations to confirm their crystallographic structure. The obtained experimental values of enthalpy of formation were −5.8 ± 0.3 and −1.3 ± 0.4 kJ/mole of atoms for ζ′-Au5Sn, and ζ-Au5Sn of the composition Au89Sn11, respectively. Using the DTA technique the transition temperatures were measured for the following phases: η-AuSn4, ɛ-AuSn2, δ-AuSn, ζ′-Au5Sn and ζ-Au5Sn (Au89Sn11). It was found that the obtained data in the study agreed very well with the results previously presented in literature, except for the ζ-Au5Sn (Au89Sn11) intermetallic phase, for which a difference of about 50° was observed for the liquidus temperature.