Effects of composition on crystallization behaviour and mechanical properties of bioactive glass-ceramics in the MgO–CaO–SiO2–P2O5 system

The effects of replacement of P2O5 by SiO2, on the crystallization behaviour, mechanical properties and bioactivity of glass-ceramics in the MgO–CaO–SiO2–P2O5 system were investigated. By decreasing P2O5 and increasing SiO2, the apatite crystallization peaks disappeared from DTA traces, whereas the wollastonite peaks remained unchanged. XRD results showed that by decreasing P2O5 and increasing SiO2 contents, the amount of apatite and wollastonite phases were decreased and increased, respectively. The diametral compression strength (DSC) and indentation fracture toughness (IFT) values gradually raised with increasing wollastonite content. The best results obtained for the specimens with the maximum amount of wollastonite were 36.6 and 2.74 MPa m1/2 for DCS and IFT, respectively. The bioactivity of specimens after being soaked in a simulated body fluid for one month were examined by SEM/EDX and FT–IR. A thin apatite layer was formed even on the surface of specimens containing the minimum amount of apatite phase.