The phase equilibria in the quasi-binary Cu2GeS3/Se3/–CdS/Se/ systems

Abstract

The phase diagram of the quasi-binary Cu2GeS3–CdS, Cu2GeSe3–CdSe and Cu2Se–GeSe2 systems was studied by DTA, X-ray diffraction, and microstructural methods. Four quaternary phases are observed in the quasi-binary Cu2GeS3/Se3/–CdS/Se/ system: Cu2CdGeS4, Cu2Cd3GeS6, Cu2CdGeSe4, and Cu2Cd3GeSe6 which melt a incongruently melting at 1282, 1329, 1103, and 1173 K, respectively. Cu2CdGeS4 and Cu2CdGeSe4 crystallize in an orthorhombic structure (space group Pmn21, a=0.7703(1), b=0.65549(9), c=0.6312(1) nm) and a tetragonal structure (space group I4̄2m, a=0.57489(5), c=1.1955(1)), respectively. The quasi-binary Cu2Se–GeSe2 system was studied in the region 15–60 mol.% GeSe2. Cu2GeSe3 melts congruently at 1053 K and crystallizes in an orthorhombic structure (space group Imm2, a=1.1857(1), b=0.39522(8), c=0.54865(7) nm)