Preparation of β-TCP/TiO2 composite by hot-pressing

In this work, tricalcium phosphate [TCP, beta-Ca-3(PO4)(2)]/titania composite were prepared with different ratio of 75/25, 50/50 and 25/75 (HA/TiO2, wt %). The TiO2 and hydroxyapatite (HA) powders, as starting materials, were synthesized by precipitation and hydrothermal methods, respectively. The sintered bodies of beta-TCP/TiO2 composite were prepared by hot pressing at pressure of 30 MPa and temperature of 800-1000 degrees C for 30 min under the pressure of 30 MPa in N-2 atmosphere. During the sintering process, hydroxyapatite 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 value of 1080 Hv in hardness, compared with the pure hydroxyapatite (600 Hv) before immersion in distilled water. Increasing sintering temperature led densification of the composite with moderately uniform microstructures. As increasing the amount of TiO2, the surface of the composite was less damaged or dissolved.