Tracking of Formed Crystalline Phases in the Binary Silver Tellurite Glass-ceramics

Abstract

Glasses and glass-ceramics based on silver tellurite system xAg₂O·(100-x)TeO₂ (0 £ x £ 60  mol%) were prepared by melt-quenching method. The structure of the studied glasses and glass-ceramics was investigated by several techniques. XRD patterns reveal the existence of only one glassy region at 20 < x ≤ 30 mol% with two crystalline a-TeO₂ and Ag₂TeO₃ phases that formed separately in the prepared samples below 20 and beyond 30 mol% Ag₂O, respectively. The peaks intensity corresponding to the crystalline a-TeO₂ and Ag₂TeO₃ phases was found to decrease and increase with Ag₂O content, respectively. This may be correlated with changes in the concentration of   and  units that, respectively, build up the crystalline a-TeO₂ and Ag₂TeO₃ phases. In the glassy region, there is no crystalline phase, which may be attributed to the abundance of the deformed  units that build up the glassy phase, and the concentrations of  and  units are neglected in this region. SEM and TEM micrographs and the related electron diffraction patterns (EDP) confirmed the formation of crystallized clusters in Ag₂O-rich glasses.