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Heavy metal oxide glasses doped with 2d transition metal niobium were casted through normal melt-quench technique in the formula composition (100?x) [3Bi2O3–7GeO2 (BGO70)]?xNb2O5 where 5 ≤ x ≤ 25. Experimentally measured values of density d exp were 6.737–7.149 g/cc ± 0.06 %. Corresponding molar volume V m exp had values 29.677–31.550 cc ± 0.04 %, V pyc varied 32.28–34.71 cc ± 0.03 % and oxygen molar volume $ V_{{{\text{mO}}^{2-} }} $ increased linearly from 17.761 to 20.467 cc ± 0.06 %. Thermal coefficient of linear expansion was between 5.316 ± 0.001 × 10?6 and 8.033 ± 0.001 × 10?6 K?1. Glass transition temperature T g, onset of crystallization temperature T x, and the stability factor ΔT were noted from DTA curves. Direct allowed energy gap E g was between 1.809–2.988 eV and Urbach energy had value 0.32–1.49 eV. Maximum transmission efficiency was 74 % for glass BGO70-Nb10. FTIR spectra revealed that lattice vibration modes were active in 400–1,300 cm?1 range. A modifying behavior was assigned to Nb5+ ion in the system. 相似文献
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Novel oxy-sulfide glass system xPbS-(73 ? x) Bi2O3–27B2O3 with 6.06 ≤ x ≤ 36.35 named lead sulfide bismuth borate (LSBB) was prepared using normal melt and quench-casting technique. Phase transition temperatures t g, t x, t pi, and t l were noted from the DTA curves. Glass transition temperature t g varied from 306 ± 2 to 336 ± 2 °C and the onset of crystallization temperatures t x was between 331 ± 2 and 402 ± 2 °C. The glasses melted in the range 523 ± 2 to 597 ± 2 °C. The ratio t g /t l showed that compositions reported conform to the two-third law of glass formation. Hruby’s coefficient H r witnessed the thermal stability of the system and that LSBB4 was most stable and glass formability factor k gl showed that composition LSBB1–LSBB6 can easily corroborate vitreous state. The direct band gap energy varied from 1.56 to 3.07 eV, while indirect band gap energy for the fundamental absorption edge was 0.21–1.31 eV. Absorption edges obeyed Urbach rule. A broad range of band tailing was exhibited confirming amorphous state of the system. 相似文献
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Khair-u-Nisa Ahmed Ejaz Ahmad Waheed 《Journal of Thermal Analysis and Calorimetry》2017,128(3):1527-1534
Journal of Thermal Analysis and Calorimetry - Equimolar Nb2O5:Li2O co-doped BGO70 (Bi2O3:GeO2 = 30:70) glasses were prepared via melt–quench method. Their XRD pattern and... 相似文献
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