20 януари 2023
Tasheva, T., Harizanova, R., Mihailova, I., Cherkezova-Zheleva, Z., Paneva, D., Nedkova, M., R?ssel, C..
(
Зара Черкезова-Желева;
)
Abstract
The high temperature synthesis of glasses in the system (100-x)(0.16Na2O/0.10CaO/0.74SiO2)/xFe2O3, x = 5 ? 20 mol% is reported. For Fe2O3 concentrations ?15 mol%, glasses are formed while the sample with 20 mol% crystallizes during cooling the melt. X-ray diffraction shows the crystallization of magnetite. The microstructure of the glass-crystalline sample is investigated by optical microscopy and scanning electron microscopy and two types of iron-rich crystals corresponding to magnetite and hematite are detected. The refractive indices as determined by the Becke line method are in the 1.567 - 1.639 range and. increase with increasing Fe2O3 concentration. The structure is characterized using Infra-red spectroscopy. The presence of symmetric stretching, asymmetric stretching and bending vibrations of Si-O-Si is detected and attributed to the occurrence of SiO4 tetrahedral units with varying numbers of nonbridging oxygens. Also, the increasing Fe2O3 concentration results in occurrence of Fe-O-Si bonds indicating the glass network depolymerization due to Fe2O3 addition. In all samples, the presence of Fe3+ and Fe2+ and the existence of iron ions in tetrahedral and octahedral coordination, as well as a very small amount of Fe0 and the precipitation of hematite and magnetite in the glass-crystalline sample is revealed by M?ssbauer spectroscopy.
International Journal of Applied Glass Science, 14, 3, John Wiley and Sons Inc, 2023, ISSN:20411286, DOI:10.1111/ijag.16626, 445-454. SJR (Scopus):0.36 Q2 (Web of Science)
https://ceramics.onlinelibrary.wiley.com/doi/abs/10.1111/ijag.16626
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