Effect of thermal treatment on the microstructure and mechanical properties of gel-derived bioglasses

Bioactive glasses have been used successfully as bone-filling materials in orthopedic and dental surgery, but their poor mechanical strength limits their applications in load-bearing positions. Approaches to strengthen materials decrease their bioactivity. In order to realize the optimal matching between mechanical and biological properties, the sol-gel-self propagating method is adopted to prepare two types of gel-derived bioglass bulk: 3S and 5S in the system SiO₂-CaO-P₂O₅-MgO. The effect of thermal treatment on the microstructure and mechanical properties of 3S and 5S is systemically studied by XRD, SEM and varieties of mechanical measurement instruments. Experiment results show that the thermal treatment at the temperature of 900-1100 °C results in the precipitation in the glass matrix: one is phosphate rich and the other silicate rich. The increase of density and the appearance of microcrystalline enhance the mechanical properties. Both 5S and 3S prepared by this method have better biological mechanical properties. Results of our study suggest that it is possible that the gel-derived bioglass bulk 5S may be used in load-bearing positions.