Thermal properties and crystallization behavior of some TeO2–K2O glasses

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

“…8 that the amount of the CdTe 2 O 5 crystals formed in the glass also increases with the annealing temperature. The transformation of the metastable ␥-TeO 2 to stable ␣-TeO 2 was also observed in other TeO 2 -based glasses such as 0.95TeO 2 -0.05K 2 O , (1 − x)TeO 2 -xZnO glasses at temperatures above 430 • C and also 0.85TeO 2 -0.15WO 3 glasses at temperatures above 440 • C. 12,15,23 On the other hand almost no structural changes were observed in TeO 2 -BaO glasses heated to different annealing temperatures and the dominant ␥-TeO 2 phase at lower temperatures did not disappear but lost its intensity. 16 …”

“…7 On the other hand glasses containing K 2 O content has shown that the T g , shifts to lower values as the K 2 O content increases. 15 As seen in Fig. 1, there are different number of peak crystallization temperatures (T p ) occurred at a range of 376-421 • C following the glass transition temperatures for three compositions.…”

“…18 The glass stability of the certain glass system can be explain by the Hurby's parameter which is The glass-forming tendency of CdF 2 containing tellurium oxide glasses is reported to be smaller than most of the existing tellurite glasses containing different modifiers. 15,16,[18][19][20][21] The K gl value for each glass composition was determined from the respective DTA curve by using the lowest crystallization and the melting temperatures observed and are listed in Table 1. The thermal stability of the 0.90TeO 2 -0.10CdF 2 glass is 88, on the other hand this value decreases to 66 for the 0.85TeO 2 -0.15CdF 2 glass and 57 for the 0.75TeO 2 -0.25CdF 2 glass.…”

Microstructural characterization and crystallization kinetics of (1−x)TeO2–xK2O (x=0.05, 0.10, 0.15, 0.20mol) glasses

“…On the basis of these relevant literature and assuming that the spectral peaks between 0 and 200 cm −1 are the Boson peaks, there remains three unidentified peaks for the crystallized 0.95TeO 2 -0.05K 2 O and 0.90TeO 2 -0.10K 2 O glasses: at 226, 285 and 331 cm −1 . Based on the XRD results of these glasses in the heat-treated condition, 17 we believe that these Table 2 Raman band assignments for the (1 − x)TeO 2 -xK 2 O glasses 11,[22][23][24][25]29 Wave number (cm three unidentified spectral peaks might belong to the K 2 Te4O 9 phase.…”

Glass transition and crystallization of 0.8TeO2+0.2CdF2 glass

“…In literature a binary TeO 2 -CdF 2 phase diagram does not exist but with the present investigation one of the possible glass forming compositions will be enlightened and studied which was found to be a non glass forming composition in earlier studies. 2,5 The glass formation in the binary TeO 2 + CdF 2 system in literature takes place with CdF 2 contents varying between none to 0.15 mol. 6 After the evaluation of the thermal properties with the help the differential thermal analysis (DTA) scans, the X-ray diffraction (XRD) and optical microscope and scanning electron microscopy/energy dispersive spectroscopy (Optical-SEM/EDS) characterizations of the glass were performed.…”