Paper PII-17

Thermodynamic Modeling of Bi-Sn-Hg Alloys

Hansen Steve¹, Janz Andreas ², Gröbner Joachim ² and Schmid-Fetzer Rainer²

¹APL Engineered Materials, Inc., 2401 N Willow Road, Urbana, IL 61802-7332, USA

²University of Clausthal, Institute of Metallurgy, Robert-Koch-Str. 42

D-38678 Clausthal-Zellerfeld, Germany

A critical evaluation of the systems needed for an assessment of the Bi-Sn-Hg has been undertaken.  An assessment of the binary Hg-Sn system [2003 Yen] was recently completed in our group.  The Sn-rich regions of the binary diagram exhibited a variety of complicated phase relationships, see Fig. 1.  Extensive literature data on the binary Bi-Hg and Bi-Sn systems have been evaluated to model the ternary system Bi-Sn-Hg.  The data set for Bi-Sn from Ohtani and Ishida [1994Oht] was checked against additional literature data and a new assessment was completed for Bi-Hg.

Fig. 1 Partial Hg-Sn phase diagram [2003Yen].

Comparisons between the experimental data and the calculations are presented.  The assessment incorporates the extensive phase diagram and thermodynamic data available for these alloys.  Enthalpy, and especially activity and vapor pressure measurements, as functions of alloy composition and temperature, were used in the modeling.   The liquidus projection of the ternary system is clarified by the calculation. 

[2003Yen]              Yee-Wen Yen, J. Gröbner, S.C. Hansen, R. Schmid-Fetzer: Thermodynamic Assessment of the Hg-Sn System. J. Phase Equilibria, 24 (4) 2003, pp. 151-167.

[1994Oht]              H. Ohtani, K. Ishida: A Thermodynamic Study of the Phase Equilibria in the Bi-Sn-Sb System. J. Electronic Materials, 23, 1994 pp. 747-755.