Thermo-mechanical behaviour of alkali free bioactive glass-ceramics co-doped with strontium and zinc

• We prepared alkali-free bioactive glass-ceramics co-doped with ZnO and SrO.
• Effect on thermal and mechanical properties was examined.
• Addition of ZnO and SrO results in decrease in Tg.
• Well sintered glass-ceramics with good mechanical properties are obtained.
• Diopside and fluorapatite based phases are the major crystalline phases.

We report on the influence of SrO and ZnO co-doping on thermo-mechanical behaviour of alkali free bioactive glass-ceramics in system: (mol%) (36.07 − x) CaO–x SrO–(19.24 − y) MgO–y ZnO–5.61 P2O5–38.49 SiO2–0.59 CaF2 (x = 2–10, y = 2–10). Hot-stage microscopy and differential thermal analysis revealed that densification of all the glass powders occurs before the onset of crystallization, resulting in well sintered and mechanically strong glasses/glass-ceramics after heat treating for 1 h under non-isothermal conditions at 800, 850 and 900 °C. The crystalline phase assemblage in the sintered compacts included diopside (CaMgSi2O6) and fluorapatite [Ca5(PO4)3F] with partial replacement of Ca for Sr with increasing strontium contents. The effect of heat treatment temperature on mechanical reliability was assessed by Weibull statistical analysis applied to the flexural strength data. The results obtained revealed that a better balance of properties was achieved for the samples sintered at 850 °C. These results provide an insight into the choice of final material/experimental conditions for the development of three-dimensional porous scaffolds for bone tissue engineering.