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Search Results: 1 - 2 of 2 matches for " Fawzeya Gharghar "
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More Insight on Structure of New Binary Cerium Borate Glasses  [PDF]
Gomaa El-Damrawi, Fawzeya Gharghar, Rawya Ramadan
New Journal of Glass and Ceramics (NJGC) , 2018, DOI: 10.4236/njgc.2018.81002
Abstract: The structure of glasses in the system of xCeO2(100?-x)B2O3, x = 30, 40, 50 mol% CeO2 has been explored for the first time by correlation between data obtained from XRD, FTIR and 11B NMR analyses. NMR spectroscopy andFTIR spectroscopy have confirmed that transformation rate of BO3 to BO4 groups is reduced by CeO2 addition.The concentration of Ce4-O-Ce4 is increased at the expense of
11B NMR Spectroscopy of Lead Borate Glasses: Additive Effect of Cerium Oxide  [PDF]
Gomaa El-Damrawi, Fawzia Gharghar, Rawia Ramadan, Mohamed Aboelez
New Journal of Glass and Ceramics (NJGC) , 2016, DOI: 10.4236/njgc.2016.64007
Abstract: Glasses and glass ceramics in the system xCeO2·(50?-x)PbO·50B2O3 (0 ≤ x ≤ 50) have been studied, for the first time, by NMR and FTIR techniques. Effect of CeO2 substitution with PbO on NMR parameters has been discussed in terms of changing both boron and cerium coordination. The quantitative fraction of four coordinated boron (N4) has been simply determined from 11B NMR spectroscopy. On the other hand, the fraction of total tetrahedral structural units B4 (BO4 + PbO4 + CeO4) is obtained from FTIR spectral analysis. It is not possible to get the fraction of cerium oxide directly from the applied spectroscopic tools. Therefore, a simple approach is applied, for the first time, to determine CeO4 fraction by using the different criteria of both 11B NMR and FTIR spectroscopy. The fraction of B4 species is equal to N4, within the experimental error, of the same glasses in the composition region of up to 10 mol% CeO2. On the other hand, there is a clear difference between both N4 and B4 values in glasses of higher CeO2 content (>10 mol%). The related difference showed a linear increasing trend with increasing the content of CeO2 in the glass. This was discussed on the bases of structural role of CeO2 which acts as a glass former in the region >10 mol%, while, at lower concentration, it consumed as a glass modifier.


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