Preparation of high-strength β-CaSiO3 bioceramic with B2O3 and SiO2 sintering additives

Calcium silicate (CS) bioceramic is a promising candidate in bone tissue engineering due to its excellent bioactivity and biodegradability. However, the deficient mechanical properties make it challengeable in hard bone tissue replacement. In this work, high-strength beta-CS bioceramics were prepared with low melting-point B2O3-SO2 sintering additives using liquid phase sintering mechanism via a versatile milling-pressing-pressureless sintering route. The results showed that the addition of B2O3-SO2 could significantly promote densification and induce the in-situ growth of beta-CS rod-like grains. beta-CS ceramics with 5 wt% addition of B2O3/SO2 with mass ratio of 92.5:7.5 sintered at 1000 degrees C for 2 h exhibited a relatively high flexural strength of 228.14 MPa, increased by 340% compared to that of pure beta beta-CS ceramic (52.08 MPa) prepared under the same conditions. The elevated strength fully qualified the strength requirement of cortical bone (135-193 MPa), indicating beta-CS ceramic reinforced with B2O3-SO2 additives had great potential in load-bearing bone repair.