Thermal analysis and in vitro bioactivity of bioactive glass–alumina composites

Bioactive glass–alumina composite (BA) pellets were fabricated in the range 95/5–60/40 wt.% respectively and were heat-treated under a specific thermal treatment up to 950 °C. Control (unheated) and heat-treated pellets were immersed in Simulated Body Fluid (SBF) for bioactivity testing. All pellets before and after immersion in SBF were studied by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM-EDS) and X-ray Diffraction (XRD) analysis. All composite pellets presented bioactive response. On the surface of the heat-treated pellets the development of a rich biological hydroxyapatite (HAp) layer was delayed for one day, compared to the respective control pellets. Independent of the proportion of the two components, all composites of each group (control and heat-treated) presented the same bioactive response as a function of immersion time in SBF. It was found that by the applied methodology, Al2O3 can be successfully applied in bioactive glass composites without obstructing their bioactive response.