Study on the fabrication and mechanical properties of HAp-3YSZ composites by flash sintering

Nano hydroxyapatite (HAp) and 3 mol% yttria-stabilized zirconia (3YSZ) composite with different proportions were prepared by flash sintering. The effects of current density and 3YSZ content on the microstructure and mechanical properties of the composites were studied. The phase, morphology and mechanical properties of the materials were characterized by XRD, SEM and microhardness tester. The results show that HAp-3YSZ composites with uniform distribution and near complete densification can be prepared by flash sintering. The increase of 3YSZ content can improve the hardness of the composite. And the phase transition of HAp can be effectively inhibited by flash sintering at low current density. Under the sintering conditions of 1050 °C, electric field intensity of 250 V/cm and current density of 30 mA mm⁻², the sample with 50 vol% 3YSZ content performed optimally, with a relative density of 99.6%, Vickers hardness of 5.26 GPa and fracture toughness of 1.36 MPa•m^0.5.