Solubility of YbTe in Sb2Te3 and thermodynamic properties of the solid solution

International audienceThe solubility of YbTe in Sb2Te3 is investigated by a combination of DTA, XRD, SEM, and EMF methods. The fragment of the T-x phase diagram of the YbTe-Sb2Te3 system is constructed for 0-25 mol.% YbTe. It is shown that the solubility limit for YbTe in Sb2Te3 is achieved at 15 mol.% YbTe at 300 K and at 17.5 mol.% YbTe at 855 K. From the EMF measurements with an YbTe electrode the partial thermodynamic functions of the YbTe pseudo-component are calculated for the alloys of different compositions. Also, the standard integral thermodynamic functions of the YbTe dissolution in Sb2Te3 as well as the standard thermodynamic functions of formation and the standard entropy of the solid solution are calculated from the experimental data

Phase diagram of the Sb-Te-I system and thermodynamic properties of SbTeI

International audienceThe Sb-Te-I system was investigated by using differential thermal analysis, X-ray diffraction analysis and electromotive force measurements with an antimony electrode. A number of polythermal sections and the projection of the liquidus surface were constructed. The fields of the primary crystallization, as well as the types and coordinates of non- and monovariant equilibriums were determined. It is shown that the quasi-binary sections SbI3-Sb2Te3, SbI3-Te, and SbI3-TeI4 triangulate the Sb-Te-I system, leading to four independent subsystems. From the electromotive force measurements, the partial molar functions of antimony as well as the standard integral thermodynamic functions of SbTeI were calculated. The latter were found to have the following values: Delta G(f,298)(0) = 55.77 +/- 1.7 kJ . mol(-1): Delta H-f,298(0) = -55.72 +/- 1.39 kJ . mol(-1); S-298(0) = 153.5 +/- 2.8 J . K-1 . mol(-1)