Thermodynamic Descriptions for the Sn-Te and Pb-Sn-Te Systems

Abstract

Thermodynamic evaluation of the Sn-Te and Pb-Sn-Te systems has been carried out using the calculation of phase diagrams (CALPHAD) method. The associated solution model is utilized to describe the thermodynamic properties of liquids in the Sn-Te and Pb-Sn-Te systems. Such a model is based on the formation of associates in the melts to account for abrupt changes in thermochemical quantities and phase diagrams. According to this treatment, the Sn-Te melts are composed of three species, Sn, SnTe, and Te, at an equilibrium state. In the Pb-Sn-Te ternary melts, only binary associates, PbTe and SnTe, are assumed to exist. Based on abundant phase equilibrium and thermochemical data, the thermodynamic behaviors of the Sn-Te and Pb-Sn-Te systems have been extensively studied. Self-consistent thermodynamic descriptions have been established, which enable a great majority of the experimental values to be well reproduced. Various calculated isothermal sections, vertical sections, and liquidus projections are presented.

Thermodynamic Optimization of the Ternary Ga-Sn-Te System Using Modified Quasichemical Model

“…The Sn-Te phase diagram consists of two eutectic reactions and one intermediate congruently melting phase, SnTe. This binary system has been thermodynamically assessed by various authors [52][53][54][55][56][57]. Hsieh et al [52], Kattner et al [53], Sharma and Chang [57], Kuznetsov [54], and Liu et al [56] used an associate solution model with SnTe as an associate component, whereas Merzhanov et al [55] used a formal mathematical model.…”

“…This binary system has been thermodynamically assessed by various authors [52][53][54][55][56][57]. Hsieh et al [52], Kattner et al [53], Sharma and Chang [57], Kuznetsov [54], and Liu et al [56] used an associate solution model with SnTe as an associate component, whereas Merzhanov et al [55] used a formal mathematical model. All proposed thermodynamic descriptions can satisfactorily reproduce reported experimental thermodynamic and phase diagram data in this system.…”

“…Shelimova and Abrikosov [68], Sha and Brebrick [69], and Rogacheva et al [70,71] determined the homogeneity range by hardness, partial pressure measurements, and lattice parameter as well as hardness measurements, respectively. The calculated phase diagram of the Sn-Te system is shown in Figure 3a along with experimental data [58][59][60][61][62][63][64][65] and the most recent optimization [56]. The calculated enlarged homogeneity range of the SnTe compound is shown in Figure 3b along with experimental data [66][67][68][69][70][71].…”

Multiphase thermoelectrics : effect of second phase in ex-SITU Cu7Te4-Bi0.4Sb1.6Te3 and in-SITU SnTe-SnSe nanocomposites

“…The mass fraction values used in the calculations for the different samples were the normalized values from TOPAS calculations. The calculated values are shown in Table 7.5: The enthalpy of formation of SnTe and SnSe is approximately -61.2 kJ/mol [174] and -47.4 kJ/mol [175] respectively. Comparing these two values with ∆H total , which was the total energy of composite system (Table 7. The proposed overview on such (meta)stability observed in the material system at different stages of processing (based on the total enthalpy of formation data in Table 7.5) is presented in Figure 7.6.…”

“…To the best of the author's knowledge, although there were reports on the enthalpy of formation of binary phases of SnTe [174] and SnSe [175], there had not been reports on the heat of formation values for the ternary Sn-Te-Se system. Thus, the value for the ternary phase was calculated qualitatively.…”