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 zeta'-Au(5)Sn, and zeta-Au(5)Sn of the composition Au(89)Sn(11), respectively. Using the DTA technique the transition temperatures were measured for the following phases: eta-AuSn(4), epsilon-AuSn(2), delta-AuSn, zeta'-Au(5)Sn and zeta-Au(5)Sn (Au(89)Sn(11)). It was found that the obtained data in the study agreed very well with the results previously presented in literature, except for the zeta-Au(5)Sn (Au(89)Sn(11)) intermetallic phase, for which a difference of about 50 degrees was observed for the liquidus temperature. (C) 2011 Elsevier B. V. All rights reserved.