Rietveld refinement of hydroxyapatite, tricalcium phosphate and biphasic materials prepared by solution combustion method

The solution combustion method was used to prepare single phase hydroxyapatite (HA), β-tricalcium phosphate (β-TCP) and biphasic calcium phosphates (BCP). The powder samples were synthesized with a Ca/P molar ratio from 1.45 to 1.67, and annealed at different temperatures. These samples have been characterized by XRD and FTIR. The amount and lattice parameters of each phase in these samples were refined by the MAUD program. The results of Rietveld refinement show that a single phase HA is obtained with Ca/P ratio of 1.67 and annealing at 1150 °C for 3 h, β-TCP is isolated with a Ca/P ratio of 1.5 after annealing at 950 °C and remains stable up to 1050 °C. Apart from above two extremes a whole range of BCP can be prepared with a favorable control of Ca/P ratios and annealing temperatures.