Study of the Ag–In–Te ternary system: I. Description of the triangle Ag 2Te–In 2Te 3–Te

Abstract

The phase diagram of the Ag 2Te–In 2Te 3–Te system was studied by DTA, DSC and XRD methods. Three ternary phases are observed in the quasi-binary Ag 2Te–In 2Te 3 section: AgIn 5Te 8, which presents a congruent melting point at 725°C and a solid–solid transition at 699°C, with tetragonal structure for the two varieties; Ag 3In 97Te 147, which presents a cubic structure, melts incongruently at 672°C; AgInTe 2, which crystallizes in a chalcopyrite-type structure at room temperature, undergoes a solid–solid transition at 410/475°C and a binary peritectic decomposition at 650°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.