Phase equilibria in the system Tl2Te-SnTe-TlBiTe2

The phase equilibria in the system Tl2Te-SnTe-TiBiTe2 (A) have been studied using differential thermal analysis, x-ray diffraction, and microhardness measurements. We have constructed the T-x phase diagrams along the SnTe-TlBiTe2, SnTe-Tl9BiTe6, and Tl4SnTe3-TlBiTe2 joins, the 600-and 800-K sections of the phase diagram of system A, and its liquidus diagram. The results demonstrate that the system contains broad ranges of Tl5Te3-structured and SnTe-based solid solutions (δ and γ1 phases, respectively). There are also relatively small fields of the Tl2Te-based phase (α) and low-and high-temperature TlBiTe2-based solid solutions (γ2 and γ′2). The liquidus surface of system A comprises the primary crystallization fields of the δ, γ1, and γ′2 phases. The liquidus of the α phase is degenerate. The ternary eutectic between the δ, γ1, and γ′2 phases melts at 755 K.