Influence Of Modifiers And Glass Forming Ions On The Bioactivity Of Glasses In The Nacapo4-Sio2 System

This paper presents research on the influence of modifying cations (K+, Mg2+) and glass forming cations (Al3+, B3+) on the bioactivity of silicate-phosphate glasses in the NaCaPO4-SiO2 system. Modifying and glass forming cations are introduced into the glass structure in order to change and/or to improve their chemical and mechanical properties. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) revealed that glasses in the NaCaPO4-SiO2 system show high bioactivity. New phases on the surface of the glasses after thermostating in simulated body fluid (SBF) are seen in SEM images and are identified using the EDX spectra. Due to their very poor crystalline, a precise identification of crystallizing phosphates by x-ray diffraction (XRD) or mid-infrared (MIR) spectroscopy could not be made. Total or partial replacement of modifying cations (Na+by K+ and Ca2+ by Mg2+) did not significantly affect the bioactivity of the glasses studied. Introduction of aluminium or boron ions into the glass structure makes all the glasses inert, except for the glasses of KCaPO4-SiO2-AlPO4 system.