Stable and Metastable Phases in Reciprocal Systems PbSe + Ag_2I_2 = Ag_2Se + PbI_2 and PbSe + CdI_2 = CdSe + PbI_2

摘要

Reciprocal system PbSe + Ag_2I_2 = Ag2_Se + PbI_2 was studied. Diagonal Ag_2Se-PbI_2 is stable. The liquidus surface and an isothermal section at 633 K for the PbSe-Ag_2Se-PbI_2 system (stable equilibria) were designed. Transformations leading to the crystallization of a metastable ternary compound in the PbSe-PbI_2 system and metastable lead iodide polytypes in the PbSe-Ag_2Se-PbI_2 system in the range 620-685 K were studied. Quenching from melt (1150-1220 K) yielded new intermediate metastable phases that crystallize in the CdCl_2 structural type in the PbSe-Ag2Se-PbI2 and PbSe + CdI_2 = CdSe + PbI_2 systems.