Microstructural dependence on relevant physical–mechanical properties on SiO 2–Na 2O–CaO–P 2O 5 biological glasses

Abstract

Bioactive glasses of the system SiO 2–Na 2O–CaO–P 2O 5 have been prepared by the normal melting and annealing technique. The elastic moduli, attenuation, Vickers hardness, fracture toughness and fracture surface energy have been obtained using the known method at room temperature. The temperature dependence of elastic moduli and attenuation measurements have been extended over a wide range of temperature from 150 to 500 K. The SiO 2 content dependence of velocities, attenuation, elastic moduli, and other parameters show an interesting observation at 45 wt% of SiO 2 by exhibiting an anomalous behaviour. A linear relation is developed for T g, which explores the influence of Na 2O on SiO 2–Na 2O–CaO–P 2O 5 bioactive glasses. The measured hardness, fracture toughness and fracture surface energy show a linear relation with Young's modulus. It is also interesting to note that the observed results are functions of polymerisation and the number of non-bridging oxygens (NBO) prevailing in the network with change in SiO 2 content. The temperature dependence of velocities, attenuation and elastic moduli show the existence of softening in the glass network structure as temperature increases.