Phase Diagram of the CdTe-CdSe Pseudobinary System

The liquidus and solidus curves of the CdTe-CdSe pseudobinary system have been determined by thermal analysis of cooling and heating curves, re-spectively, for homogenized liquid and solid alloy samples. The phase diagram has a eutectie point at 1091 ~ • 1 ~ near 20 m/o (mole per cent) CdSe. Above the eutectic composition both liquidus and solidus temperatures increase monotonically and sublinearly with increasing CdSe content. In this region the experimental values of the liquidus-solidus gap do not exceed i I m/o and are in excellent agreement with the ideal thermodynamic l iquidus-solidus relationship. The phase diagram below the solidus has been investigated by x-ray diffraction measurements on alloy powders annealed between 770 ~ and 1050 ~ and quenched. It consists of two broad single-phase regions, one of alloys with the zinc blende structure of CdTe and the other of alloys with the wurtzite structure of CdSe, separated by a two-phase region only about 3 m/o wide, whose boundaries hift toward increasing CdSe content with decreas