Effect of the surface chemistry on the stability and mechanical properties of the Zirconia-Hydroxyapatite bioceramic

•Fabrication of high porous HAP-10%ZrO2 nanocomposite powder by soft chemistry.•Effect of associated ZrO2 on microstructural characterization of hydroxyapatite.•Mechanical properties were assessed by the Brazilian and Vickers tests.•The micro-cracks, particle size and porosity affect the densification.•Effects of the sintering temperature on the densification and mechanical properties of the bioceramic were studied.•HAP-10%ZrO2 bioceramic sintered at 1300°C exhibits excellent mechanical properties. Hydroxyapatite/zirconia powders were produced by soft chemistry and characterized by several techniques. The effects of the sintering temperature on the densification, microstructure and mechanical properties of the bioceramics were studied. The HAP-10%ZrO2 bioceramic was chosen for its specific advantages. Microstructural and textural characterization reveal disappearance of the microporosity in certain areas of the sample to form dense blocks whose size increases progressively as a function of the sintering temperature. Mechanical properties were assessed by the Brazilian and Vickers tests. Young and shear moduli were calculated from the longitudinal and transverse ultrasonic velocities, respectively. Above 1300°C, the mechanical strength, Vickers hardness, Young and shear moduli reach maximum values of 30 MPa, 2336 MPa, 81 GPa and 34 GPa, respectively. Rupture of the studied bioceramic is totally intergranular around 1300°C. We find that microstructure, porosity and the sintering process govern the development of the HAP-10%ZrO2bioceramic.