DESCRIPTION OF THE AG-GA-TE TERNARY-SYSTEM

The phase diagram of the Ag-Ga-Te system was studied using differential thermal analysis, X-ray diffraction and metallography. Three ternary compounds were observed on the Ag2Te-Ga2Te3 line: Ag9GaTe6, which has a congruent melting point and a phase transition at 29-degrees-C, being hexagonal on both sides of this temperature; AgGaTe2, which is a tetragonal, chalcopyrite type phase; a lacunar phase Ag(x)Ga(4-x)/3-square(2-2x)/3Te2 which is a solid solution for 0.63 less-than-or-equal-to x less-than-or-equal-to 0.75, has a stability domain between 585 and 700-degrees-C, and is an incongruent melting binary type. Two ternary solid solutions were present, one a sphalerite type on the Ag2Te-Ga2Te3 line next to Ga2Te3 and one a GaTe type on the GaTe-Ag line. One liquid-liquid immiscible phase was observed, but no glasses. Sixteen ternary invariants are characterized: eight eutectics, one of which is generated at the gallium apex, seven ternary transitory peritectics and one true peritectic binary type.