High temperature XRD studies of nanoscale AgI–CuI solid solutions

A preliminary high-temperature X-ray diffraction (HT-XRD) study of the nanometer-sized solid solution phases in the AgI–CuI system is reported through an extended range of temperatures (300–723K) covering phase transitions in both AgI and CuI. A major feature of this work is the observation of the coexistence of the zincblende and base-centred cubic phases of AgI over an extended range of temperatures the temperature width being a function of Cu content in the binary. The lattice parameters derived from HT-XRD data reflect systematics of phase transitions with progressive Cu substitution of AgI. The present results are discussed together with our earlier ionic conductivity, dilatometry and DSC data which have helped deduce phase diagrams for both the Ag-rich and Cu-rich regions of the binary.