PHASE EQUILIBRIUMIN THE Cu2S – In2S3 – CuI QUASI-TERNARY SYSTEM

Abstract

The interaction between the components in the Cu 2 S – In 2 S 3 – CuI system has been inverstigated by methods of X-ray analysis and differential-thermal analysis. An isothermal section of the quasi-ternary system at 770 K, two phase diagrams, three polythermal sections and the liquidus surface projection of the system were constructed. The isothermal section of the Cu 2 S – In 2 S 3 – CuI quasi-ternary system at 770 K has been built based on the results of the X-ray analysis. The large regions of the solid solutions based on binary, ternary and quaternary compounds do not form at 770 К. The following one-phase regions were fixedat the temperature: κ-solid solutions based on Cu 2 S with cubic structure (S.G. Fm -3 m ), η-solid solutions based on CuI (S. G. F -43 m ), e-solid solutions based on CuIn 2 S 3 I with a cubic structure (S. G. F -43 m ), δ′-solid solutions based on LTM-In2S3 (S.G. I -4/ amd ), μ-solid solutions based on CuIn 5 S 8 (S.G. Fd 3 m ), γ-solid solutions based on LTM-CuInS 2 (S.G. I -42 d ). These single-phase regions are separated by nine two-phase equilibria. The liquidus surface projection was built based on the two phase diagrams of In 2 S 3 –CuI and CuInS 2 – CuI systems and three polythermal sections CuIn 5 S 8 –CuIn 2 S 3 I, CuInS 2 –CuIn 2 S 3 I, CuInS 2 – “Cu 3 SI”, which have been constracted in this work. In addition, literature data about the interaction in In 2 S 3 – Cu 2 S and Cu 2 S – CuI systems have been used. The liquidus surface projection consists from the areas of primary crystallization of κ-solid solutions based on Cu 2 S, α-solid solutions based on HTM-CuInS 2 , β-solid solutions based on 2-HTM-CuInS 2 , γ-solid solutions based on LTM-CuInS 2 , μ-solid solutions based on CuIn 5 S 8 , δ-solid solutions based on HTM-In 2 S 3 , e-solid solutions based on CuIn 2 S 3 I, η-solid solutions based on CuI. These areas are separated by 18 mono-variant curves and 17 non-variant points.