Effect of the Titanium Dioxide Addition on the Mechanical Performance of the Tricalcium Phosphate Bioceramics

The effect of the titanium dioxide addition on the mechanical properties of tricalcium phosphate was investigated. The samples were compacted into cylinders under 150 MPa as a load compression. Then, the specimens were sintered at various temperatures for 1 h in a vertical programmable muffle furnace. Beyond the sintering process, the compacted samples were characterized by Brazilian test and Vickers hardness. Both the microstructure and the mechanical properties showed significant evolution with the sintering temperature. The mechanical performances of the tricalcium phosphate-titanium dioxide composites have been improved with the sintering temperature and the titanium dioxide addition. At 1200 ℃, the optimum values of the rupture strength and Vickers hardness of the tricalcium phosphate sintered with 40 wt% titanium dioxide composites reached 33 MPa and 270 Hv, respectively. This significant improvement is due to both formation of the calcium titanate (CaTiO3) and the liquid phase. The liquid-phase formation resulted from a solid interaction between the tricalcium phosphate and the titanium dioxide. The liquid phase formation helped to fill the pores in the microstructure of the composites. Above 1200 ℃, the mechanical performances of the composites were hindered by the exaggerated grain growth phenomenon.