Bioactivity of ferrimagnetic MgO-CaO-SiO_2-P_2O_5-Fe_2O_3 glass-ceramics

摘要

Glass-ceramics with compositions 4.5MgO(45 - x)CaO34SiO_2 16P_2O_5 0.5CaF_2 xFe_2O_3 (where x = 0, 5, 10, 15 and 20 wt.%) were obtained by heat-treatment of melt quenched glasses at 1050 °C. Hydroxyapatite, magnetite and wollastonite were identified as major crystalline phases in all the glass-ceramic samples containing iron oxide. Akermanite was detected in glass-ceramic samples with high iron oxide content. Evolution of magnetic properties in the glass-ceramic samples as a function of iron oxide concentration is correlated with the amount of magnetite phase. Bioactivity of the glass-ceramic samples treated for various time periods in simulated body fluid (SBF) was evaluated by examining the apatite layer formation on their surface using X-ray diffraction, Fourier transform infrared reflection spectroscopy, scanning electron microscopy and energy dispersive spectroscopy techniques. Increase in bioactivity was observed as the iron oxide content was increased. The results help in understanding the evolution of the apatite surface layer with respect to immersion time in SBF and composition of the glass-ceramic samples.