Effect of iron oxide addition on structural properties of calcium silico phosphate glass/glass-ceramics

Glasses with nominal composition 34SiO2–(45 − x) CaO–16 P2O5–4.5 MgO–0.5 CaF2–x Fe2O3 (where x = 5, 10, 15, 20 wt.%) have been synthesized by melt quench technique. These have been investigated for structural features by using Fourier transform infra-red (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Results have shown an increase in fraction of non‐bridging oxygen in glasses with an increase in iron oxide content up to 15 wt.% and subsequently decreases with further increase in iron oxide content to 20 wt.%. These effects are originated by the incorporation of Fe2O3 into the silica network. Iron oxide behaves as a network modifier at low concentration and stabilizes the glass network at higher content. The glass-ceramics exhibit an increase in the formation of magnetite phase with an increase in iron oxide. The glass phase in the glass-ceramics matrix, controls the surface dissolution, which in turn decides the response of the material in-vitro. The glass-ceramics with 15 wt.% iron oxide has shown optimum response in simulated body fluid.

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► Fraction of non-bridging oxygen increases with incorporation of iron oxide up to 15 wt.%.
► Fraction of non-bridging oxygen's controls the surface dissolution.
► Glass-ceramics exhibit an increase in the formation of magnetite phase with an increase in iron oxide.
► The glass-ceramics with 15 wt.% iron oxide has shown optimum response in SBF.