Enhanced mechanical property of Ca5(PO4)2SiO4 bioceramic by a biocompatible sintering aid of zinc oxide

In the present work, a biocompatible additive ZnO was used to enhance the sintering of calcium phosphate silicate (CPS)1 bioceramic and improve its mechanical property. Sol-gel prepared CPS powders were mechanically mixed with various amount of ZnO and then sintered at high temperatures to prepare Zn-CPS bioceramics. The effects of ZnO content and sintering temperature on microstructure and bending strength of Zn-CPS bioceramics were investigated and the related mechanism was also discussed. The results showed that ZnO could significantly enhance the sintering of CPS and improve its bending strength accordingly. The Zn-CPS bioceramic with 1 wt% ZnO sintered at 1300 °C exhibited a highest bending strength of 80.8 MPa. The enhanced densification of Zn-CPS bioceramics might be attributed to the liquid phase appeared during the sintering process and the formation of Ca2ZnSi2O72 (HT) nano-grains at grain boundaries. It is expected that Zn-CPS bioceramics could have both good mechanical property and excellent bioactivity.