Effects of CdF2 and WO3 additions on the microstructural and thermal properties of TeO2–CdF2–WO3 glass system

Abstract

Abstract This paper presents microstructural characterization investigations and the crystallization behavior of some glasses in the ternary TeO 2 –CdF 2 –WO 3 system. Differential thermal analysis (DTA) showed that the glass forming ability of the ternary TeO 2 –CdF 2 –WO 3 system which is in between the values of 21 and 34, is lower than most of the studied tellurite glasses. It is possible to obtain amorphous glass structure for the compositions of 0.80TeO 2 –0.10CdF 2 –0.10WO 3 and 0.75TeO 2 –0.10CdF 2 –0.15WO 3 . On the other hand, the 0.85TeO 2 –0.10CdF 2 –0.05WO 3 and 0.75TeO 2 –0.15CdF 2 –0.10WO 3 compositions do not form glass with conventional quenching techniques. During crystallization of these glasses, the formation of the alpha, delta and gamma TeO 2 , WO 3 and CdTe 2 O 5 phases were observed with the addition of a new unidentified phase. Three compositions of 0.85TeO 2 –0.10CdF 2 –0.05WO 3 , 0.80TeO 2 –0.10CdF 2 –0.10WO 3 and 0.75TeO 2 –0.10CdF 2 –0.15WO 3 demonstrated two exothermic peaks in the DTA curves. SEM/EDS investigations confirmed the existence of the alpha, delta and gamma TeO 2 , WO 3 and CdTe 2 O 5 phases for the annealed glasses. The microstructure of the δ-TeO 2 phase was clearly observed in the as-cast 0.75TeO 2 –0.10CdF 2 –0.15WO 3 composition.