Correlation between acoustical and structural properties of glasses: Extension of Abd El-Moneim model for bioactive silica based glasses

Autor: Amin Abd El-Moneim
Rok vydání: 2016
Předmět:
Zdroj: Materials Chemistry and Physics. 173:372-378
ISSN: 0254-0584
DOI: 10.1016/j.matchemphys.2016.02.025
Popis: Correlation between room temperature ultrasonic attenuation coefficient and the most significant structural parameters has been studied in the bioactive silica based glasses, for the first time. The correlation has been carried out in the quaternary SiO2–Na2O–CaO–P2O5 glass system using the two semi-empirical formulas, which have been presented recently by the author. Changes in the elastic properties, related to the substitution of SiO2 by alkali Na2O and alkaline earth CaO oxides, have also been deduced by evaluating the mean atomic volume, packing density, fractal bond connectivity and density of the analogous crystalline structure. Furthermore, values of the theoretical elastic moduli have been calculated on the basis of Makishima-Mackenzie theory and compared with the corresponding observed values. Results show that the correlation between ultrasonic attenuation coefficient and the oxygen density, average atomic ring size, first-order stretching force constant and experimental bulk modulus was achieved at 5 MHz frequency. Values of the theoretically calculated shear modulus are in excellent correlation (C. R. ≻95%) with the corresponding experimental ones. The divergence between the theoretical and experimental values of bulk modulus has been discussed.
Databáze: OpenAIRE
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