Phase Diagram of the System Tl2Te–Tl5Te3–Tl9GdTe6

The ternary system Tl–Gd–Te within the composition range Tl 2 Te–T l5 Te 3 –T l9 GdTe 6 was studied by a set of physicochemical analysis methods. Some internal polythermal sections and the isothermal section at 300 K of the phase diagram were built, projections of the liquidus and solidus surfaces were constructed, and the graphs of the concentration dependences of the parameters and microhardness were plotted. It was shown that much (more than 90%) of the area of the concentration triangle is occupied by the homogeneity region of solid solutions with the Tl 5 Te 3 structure (δ-phase). Solid solutions based on Tl 2 Te (α-phase) form within a narrow region. The regions of the α- and δ-phases are separated by two-phase region α + δ.