Microstructural characterization and crystallization of (1 − x)TeO2-xCdF2 (x = 0.10, 0.15, 0.25 mol) glasses

The differential thermal analysis (DTA), X-ray diffractometer and scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) techniques were used to investigate the microstructural characterization and the thermal behavior of the three (1 − x)TeO2-xCdF2 (x = 0.10, 0.15, 0.25 mol) glasses. The effect of the heating rate, annealing temperature and CdF2 content on the thermal and the microstructural properties of TeO2-CdF2 binary glasses were enquired. DTA analysis has shown that as the CdF2 content in the glass composition increases, the value of the glass transition and the peak crystallization temperatures shift to higher values. SEM/EDS investigations have shown that the crystal formation of α-TeO2, γ-TeO2 and CdTe2O5 crystal phases were observed when the 0.90TeO2-0.10CdF2 and the 0.85TeO2-0.15CdF2 glass samples were annealed to temperatures above the crystallization temperatures. X-ray diffraction (XRD) results illustrated clearly the transformation of the metastable γ-TeO2 phase to stable α-TeO2 crystalline phase as the annealing temperature was increased from 385 to 425 °C for the 0.75TeO2-0.25CdF2 glass.