Fabrication and Characterization of Dense Bulk HA-Titania Composite by Two Step Sintering Method

Hydroxyapatite [HAp; Ca10(PO4)6(OH)2] biocomposites are ceramic materials that exhibit excellent bioactivity, but their inherent low mechanical behavior render them unusable for practical applications. Titania (TiO2) is added to improve inmechanical properties without diminution of biocompatibility. Two Step Sintering (TSS) has been applied, in the present work, to suppress the accelerated grain growth of Hydroxyapatite and Titania nanoparticles in the HA-TiO2 composites in the last sintering stage. Samples characterized by X-Ray diffraction and scanning electron microscopy. It was shown by application of this method, the final grain size of HA-15wt.%TiO2 maintainslower than 100nm while by application of conventional sintering it reaches higher than 100nm. The optimum regime consisted of heating the green bodies up to 1150˚C in the first step of sintering and then holding at 1050˚C for about 25h in the second step. This yielded the finest microstructure with no exaggeration in grain growth and density of specimens reaches higher than 95% theoretical density.