Experimental investigation and thermodynamic calculation of excess enthalpies in the Ag–Pb–Te system

Thermodynamic Description of the Ag-Pb-Te Ternary System

“…12 and 13 respectively. A difference between calculated function and the experimental data [11] is less than 1000 J. In this case we can say that enthalpy of mixing of the ternary Ag-Pb-Te system is reproduced well by our parameters.…”

“…Enthalpy of mixing of the liquid phase was measured by Romermann and Blachnik. [11] [12] and Blachnik and Bolte. [13] Blachnik and Gather [12] investigated the cross-section Ag 2 Te-PbTe.…”

Evolution of phase segregation and eutectic structures in AgPb18SbTe20

“…The degree of interactions should be determined by the absolute values of mixing enthalpies. Since the mixing enthalpy of Ag 2 Te (−20 kJ/mol at 1000 °C ) in liquid state is higher than that of Sb 2 Te 3 (−10 kJ/mol at 645 °C and −7 kJ/mol at 900 °C), the formation of Ag–Te associates is more favorable than Sb–Te neighborhoods in the liquid that consists mostly of about 90 mol.% PbTe with enthalpy of mixing −26 kJ/mol at 937 °C. This could cause the formation of possible solid solution of PbTe–Ag 2 Te (a rocksalt phase) leading to secondary phases such as phase 13 in the current case upon quenching.…”

“…In a quasi‐ternary system such as PbTe–Ag 2 Te–Sb 2 Te 3 one could expect the chances and priority for the formation of tellurides must be driven by their thermodynamic stability especially with regard to Ag 2 Te and Sb 2 Te 3 in LAST‐18 system where they are present in equal amounts (each 5 mol.%). It was reported that the enthalpies of mixing in liquid phase, metal–tellurium alloys often vary as triangular‐shaped functions of the concentration with exothermic minima close to the composition of congruent melting compounds such as PbTe, Ag 2 Te and Sb 2 Te 3 in the Pb–Te, Ag–Te and Sb–Te systems, respectively . This behavior can be explained by the formation of stoichiometric associates in the liquid state due to electron transfer from the metal to the chalcogen or formation of covalent bonds between these elements suggesting strong interactions creating some sort of short‐range order in the liquid.…”