Effect of Y-TZP addition on the microstructure and properties of titania-based composites

To maintain the bioactivity and to improve the mechanical properties of titania, both pure titania ceramics and titania–yttria-stabilized tetragonal zirconia (Y-TZP) composites with 5, 10, and 15 vol.%Y-TZP were prepared via a sol–gel precipitation method. A titania precursor (titanium butoxide) was mixed with a submicron-sized Y-TZP powder, followed by hydrolysis-condensation reactions, green compact forming, and sintering in air at 1200–1350 °C. It was found that the addition of Y-TZP resulted in reduced rutile titania grain size from 13 to 3 μm. The Y-TZP tetragonal phase also resulted in improved mechanical properties of the titania–Y-TZP composites. For instance, the titania–15 vol.%Y-TZP composite had a hardness value of 983 kg/mm2, a bending strength of 160 MPa, and a fracture toughness of 3.79 MPa m0.5. While the addition of Y-TZP increased the mechanical properties, it also decreased the bioactivity of the composites.