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Study Some Physical Properties of the Semiconducting P2O5 - V2O5 - As2O3 - Fe2O3 Oxide Glasses |
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PP: 55-65 |
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Author(s) |
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M. Shapaan,
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Abstract |
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| Oxide glasses with composition 35P2O5 (45-x)V2O5 xAs2O3 20Fe2O3 (0 ≤ x ≤ 25 mol %) have been prepared by the conventional melt quenching technique. The glassy state of the as prepared samples is characterized using X-ray diffraction (XRD) and differential thermal analysis (DTA). In order to understand the effect of As2O3 contents on the structure and the structural changes occurring in these glasses, the density, ρ, and molar volume, Vm, measurements have also been made. The density increases and molar volume decreases with increasing As2O3 contents. The dc conductivity decreases with increasing As2O3 contents. The room temperature dc conductivity is typically 10-5 - 10-9 (Scm-1) with activation energy 0.28 - 0.49 (eV). Two glass transition temperatures, Tg1 and Tg2, are detected at the DTA traces of the investigated glass system. From the dependence on heating rates of, Tg1, Tg2, and Tp, the activation energies for glass transitions, Eg1, Eg2, and the activation energy for crystallization, Ec, are calculated. All the results confirmed that, the thermal stability increases with increasing As2O3 contents in the investigated glass system. The glass sample with x = 25 (mol %) is of the highest glass thermal stability ΔTx = 207 ± 2 (K) at 20 (K/min) heating rate and crystallization activation energy Ec = 224.5 ± 3 (kJ/ mol). |
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