Study of the Ag–In–Te ternary system I. Description of the triangle Ag2Te–In2Te3–Te

The phase diagram of the Ag2Te-In2Te3-Te system was studied by DTA, DSC and XRD methods. Three ternary phases are observed in the quasi-binary Ag2Te-ln(2)Te(3) section: AgIn5Te8, which presents a congruent melting point at 725 degrees C and a solid-solid transition at 699 degrees C, with tetragonal structure for the two varieties; Ag3In97Te147, which presents a cubic structure, melts incongruently at 672 degrees C; AgInTe2, which crystallizes in a chalcopyrite-type structure at room temperature, undergoes a solid-solid transition at 410/475 degrees C and a binary peritectic decomposition at 650 degrees C. The eutectic valleys are drawn, and the nature and the location of the ternary invariants are given. Eight ternary invariants were found: two ternary eutectics points, five transitory ternary peritectic points and one metatectic point. No liquid-liquid miscibility gap and no glassy region are observed. (C) 1999 Elsevier Science S.A. All rights reserved.