Densification and strengthening of tricalcium phosphate/titania composite by hot pressing

Tricalcium phosphate [TCP, beta-Ca-3(PO4)(2)]/titania composite having high mechanical properties was prepared and characterized. The TiO2 and HAp powders, as starting materials, were synthesized by precipitation and hydrothermal methods, respectively. The sintered beta-TCP/TiO2 composite was prepared by hot pressing at 1000 degrees C for 30 min under the pressure of 30 MPa in N-2 atmosphere or by pressureless sintering at 1200 degrees C for 2 h in air with moisture protection. The influence of sintering condition on the microstructures and mechanical properties of the composite was investigated. During the sintering process, hydroxyapatite used as a starting material was decomposed to beta-TCP and CaTiO3 at elevated temperature because TiO2 could accelerate the decomposition of hydroxyapatite. The hot-pressed composite with 98% of sintered density showed high hardness value of 1080 Hv compared with the pure hydroxyapatite (600 Hv).