Phase evolution and sintering kinetics of hydroxyapatite synthesized by solution combustion technique.

Solution combustion technique has been used to prepare hydroxypatite (HAp) powder from calcium nitrate, di-ammonium hydrogen phosphate and citric acid precursors. Phase evolution has been studied as a function of calcination temperatures. The crystal structure, phase purity and stiochiometry of phase have been studied by Rietveld analysis of the calcined powder. It was observed that the prepared Hap powder was phase pure and stoichiometric. The sintering behaviour and sintering kinetics of the HAp compact has been studied by dilatometer. Activation energy for sintering has been calculated from the dilatometer results. Grain boundary diffusion was found to be the dominant densification mechanism during the initial stage of sintering. The activation energy for sintering (438 kJ/mol) was found to be in excellent agreement with reported value.