Effect of the partial substitution of K2O, MgO, B2O3 for CaO on crystallization, structure and properties of Na2O-CaO-SiO2-P2O5 system glass-ceramics

Na2O-CaO-SiO2-P2O5 (45S5) system ceramics, in which CaO is partly replaced by K2O, MgO or B2O3, have been obtained by the sol-gel method. The crystallization, structure, mechanical properties and in vitro bioactivity of glass-ceramic were investigated. Results indicated that the doping ions in glass have remarkably improved the volume density, bending strength, fracture toughness and microhardness of the glass-ceramics. The addition of K2O and B2O3 decreased the integrity of glass network, promoted glass crystallization and crystallization did not inhibit glass bioactivity. The addition of MgO made the glass network much denser and decreased the ability of apatite induction.