Characterisation of Ga2O3–Na2O–CaO–ZnO–SiO2 bioactive glasses

• Published in: Journal of materials science 2013-06, Vol.48 (11), p.3999-4007
• Main Authors: Wren, A. W., Keenan, T., Coughlan, A., Laffir, F. R., Boyd, D., Towler, M. R., Hall, M. M.
• Format: Article
• Language: English
• Subjects: Amorphous materials; Bioglass; Characterization and Evaluation of Materials; Chemical equilibrium; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Gallium oxides; Materials Science; NMR; Nuclear magnetic resonance; Organic chemistry; Photoelectrons; Polymer Sciences; Raman spectroscopy; Silicon dioxide; Solid Mechanics; Spectrum analysis; Zinc oxide
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-013-7211-2

The structural role of Gallium (Ga) is investigated when substituted for Zinc (Zn) in a 0.42SiO 2 –0.40– x ZnO–0.10Na 2 O–0.08CaO glass series, (where x  = 0.08). Each starting material was amorphous, and the network connectivity (NC) was calculated assuming Ga acts as both a network modifier (1.23), and also as a network former. Assuming a network forming role for Ga the NC increased with increasing Ga concentration throughout the glass series ( Control 1.23, TGa - 1 2.32 and TGa - 2 3.00). X-ray photoelectron spectroscopy confirmed both composition and correlated NC predictions. Raman spectroscopy was employed to investigate Q-structure and found that a shift in wavenumbers occurred as the Ga concentration increased through the glass series, from 933, 951 to 960 cm −1 . Magic angle spinning nuclear magnetic resonance determined a chemical shift from −73, −75 to −77 ppm as the Ga concentration increased, supporting Raman data. These results suggest that Ga acts predominantly as a network former in this particular Zn-silicate system.