Study of the YbTe-SnTe-Sb2Te3 quasi-ternary system

The phase equilibria in the YbTe-SnTe-Sb2Te3 system were investigated by using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDS) techniques. Isothermal sections of the phase diagram at 300, 700, 900 and 1000 K, the liquidus surface projection as well as some isopleth sections were experimentally constructed. The primary crystallization fields of phases, the type and coordinates of invariant and monovariant equilibria were determined. The boundary YbTe-SnTe system restudied and existence of the ternary compound YbSnTe2 reported earlier was not confirmed. Moreover, the continuous solid solution series with the NaCl type cubic structure system was revealed in this system and it was also found that a spinodal-type phase decomposition of this solid solution occurs below ∼950 K.