Phase equilibria study in systems Tl-Pb(Nd)-Bi-Te new phases of variable composition on the base of Tl9BiTe6

By DTA, X-ray diffraction, EMF methods and microhardness measurements, the phase equilibria on the concentration sections Tl5Te3-Tl4PbTe3-Tl9BiTe6 (I), Tl2Te-Tl4PbTe3-Tl9BiTe6 (II), Tl5Te3-Tl9NdTe6-Tl9BiTe6 (III) and Tl2Te-Tl9NdTe6-Tl9BiTe6 (IV) of the multinary systems Tl-Pb(Nd)-Bi-Te were investigated. A number of isopleth sections, projections of liquidus and solidus surfaces of the systems (I)–(IV) were constructed. The concentration dependences of crystal lattice parameters, microhardness and of partial thermodynamic functions of thallium (ΔG¯,ΔH¯,ΔS¯) in alloys were determined. The investigated systems are characterized by formation of continuous (I, III) or wide (II, IV) areas of solid solutions based on Tl5Te3 compound.