Thermodynamic assessment of the Hg-Sn system

A thermodynamic assessment of the Hg-Sn system has been carried out using the CALPHAD method. The comprehensive assessment covers the extensive phase diagram data as well as the enthalpy, activity, and vapor pressure data. Two cases of intermetallic compounds in the Hg-Sn system are considered. Case 1 considers the intermetallic compounds beta, gamma, and HgSn4 as having no solubility and can thus be treated as the stoichiometric phases beta-HgSn38, gamma-HgSn12, and HgSn4. Case 2 uses a sublattice model to more accurately describe a solubility of the gamma phase; it also considers the stoichiometric delta-HgSn7 Phase. The E phase was considered to be metastable and neglected in the thermodynamic assessment. Thermodynamic parameters have been optimized using all the assessed experimental thermodynamic and phase equilibrium data. Both calculated phase diagrams of the Hg-Sn system (Cases 1 and 2) and the thermodynamic data are reasonable and satisfactory when compared with literature data. Future crucial experiments are suggested.