Effect of titanium addition on mechanical properties of hydroxyapatite - Titanium nanocomposite

Hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂), having similar chemical and crystallographic structures to bone, is attractive with its bioactivity which can form a chemical bond with osseous tissue. Synthetic HA exhibits excellent osteoconductive properties. In other words, synthetic HA have the ability to provide the appropriate, scaffold or template for bone formation. The nano sized HA can be synthesized by using microwave technique. Microwave has the advantages of rapid growth, small particle size and narrow particle size distribution due to fast homogenous nucleation. Calcium oxide (CaO) was obtained by calcining egg shells at 900 °C for 2 hours. Nano HA was synthesized by mixed of di-ammonium hydrogen phosphate (DAP) and calcium hydroxide, Ca(OH)₂ and subjecting to microwave for 30 minutes at 1100 W irradiation power. Single phase HA was identified from XRD patters of the samples. The mean crystalline size of nano-HA from microwave processing was found to be in the range of 35-39 nm. Green compact of nano-HA and Ti were prepared with varying amounts of Titanium (10, 20, 30 wt. %) and sintered at 1000 °C. Pellets with 20 wt.% Ti were found to exhibit superior mechanical properties with a hardness and compression strength values of 317.0 Hv and of 66.37 MPa respectively. Scanning Electron Microscopy (SEM) micrographs showed that the grain boundary Ti is porous and has resulted in inferior densification during sintering process.