Microstructural development and mechanical performance of CaSiO3–Ca3(PO4)2 bioceramics following the addition of CaSiO3–Ca3(PO4)2–MgCa(SiO3)2 eutectic glass

Abstract This study aims to investigate the effects of adding CaSiO3–Ca3(PO4)2–MgCa(SiO3)2 eutectic glass on the sinterability, microstructure, and mechanical properties of CaSiO3–Ca3(PO4)2 bioceramics. The CaSiO3–Ca3(PO4)2 (80/20 wt%) bioceramics with 30 vol% CaSiO3–Ca3(PO4)2–MgCa(SiO3)2 eutectic glass sintered at 1245 °C for 4 h showed a biaxial flexural strength and fracture toughness of 228 MPa and 1.7 MPam1/2, respectively, which were considerably higher than those of pure CaSiO3–Ca3(PO4)2 bioceramics (165 MPa, 0.8 MPam1/2) fabricated under the same conditions. In contrast, the elastic modulus of these new composites decreased to 93 GPa, which is similar to that of the human cortical bone. X-ray diffraction and scanning electron microscopy observation indicated that the main phase after sintering was β-CaSiO3 with an elongated morphology. These results indicate the applicability of CaSiO3–Ca3(PO4)2–MgCa(SiO3)2 eutectic glass as an “active agent” for the formation of rod-like β- CaSiO3 crystals, which improve the flexural strength and toughness by a crack deflection and bridging mechanism. The favourable mechanical properties and adjustable microstructure of these new bioactive and degradable bioceramics make them ideal candidates for bone tissue engineering applications.