Conventional precipitation routes for the production of hydroxyapatite require up to 3 days to progress from raw materials to powder product. One way of accelerating production is by microwave-assisted synthesis. To date, literature on the microwave-assisted synthesis of hydroxyapatite is scarce, and phase-purity of the sintered powders has not been addressed. This paper describes the microwave-hydrothermal synthesis of hydroxyapatite powder. The reactants used were AnalaR Grade Ca(OH)2 in aqueous suspension and a solution of H3PO4. The microwave cavity used was a multimode domestic oven. By careful control of reactant calcium to phosphorus ratio and microwave operating conditions, phase-pure hydroxyapatite powder was produced (HA2). Second phases were not detected from XRD analysis of the as-precipitated powders On sintering the samples at 1200°C for 2 hours, only the sample HA2 was a single-phase hydroxyapatite. Reducing the reaction time gave rise to a secondary phase of TCP in the sintered product (HA1). Adding the H3PO4 in stages into the reacting mixture, gave rise to a secondary phase of CaO (HA3). The phase-pure hydroxyapatite powder (HA2) was found to have a median particle size of 51μm without processing.
