Fabrication and characterization of bioglass-modified HA-ZrO₂biocomposites

Hydroxyapatite (HA) being the main mineral constituent of human hard tissues is highly bioactive. Good chemical bonds can be generated between HA and natural bone. However, the low strength and inherent brittleness of HA restrict its application usually to non-load-bearing conditions. In this work, production of a new kind of HA-ZrO2composite by hot-press sintering method is described. Bioglass which has been widely used in reconstruction of damaged or diseased tissues was added into HA-ZrO2composites. Comparing with pure HA ceramic, this type of composite possesses better mechanical strength and retains the bioactivity of HA as well. The liquid phase generated by bioglass has been effective in improving the sintering process of HA-ZrO2composites. The phase composition of HA composite was characterized by XRD and their fracture surfaces were observed by SEM. The XRD results show that introducing a small amount of bioglass into HA-ZrO2composite cannot enhance decomposition of HA. The SEM images show that there were fewer pores on the fracture surfaces of HA-ZrO2-bioglass composite than in the HA-ZrO2composite. The flexural strength and toughness of HA-ZrO2composite containing 2 wt% bioglass were 157 MPa and 1.63 MPa•m1/2, respectively.