EFFECT OF CA/P AND PH IN THE WET-SYNTHESIS REACTION ON THE FORMATION OF DIFFERENT CALCIUM PHOSPHATE PHASES

Recently, there has been a growing new paradigm to use synthetic calcium phosphate biomaterials as bone substitutes in orthopedics applications. their structure and composition are close to the human bone, and thus conferring them a good biocompatibility and osteoconductivity. wet process is normally used for the synthesis of hydroxyapatite (ha) and beta-tricalcium phosphate (β-tcp). however, the wet process was reported to be less reproducible for fabrication of pure apatitic phases in comparison to other synthesis processes. in this study, it is hypothesized that a specific apatitic phase that is normally obtained from stoichiometric reaction can be synthesized by using non-stoichiometric based reactants in a reproducible way by controlling the ph value during the synthesis process. a factorial design with two factors and three repeats was implemented to examine the hypothesis [a: ca/p (1.5, 1.55, 1.667) and b: ph (7.5, 9.5)]. all precipitated powders were dried and aged overnight and then sintered for 2 hours at 800 °c. the powders were analyzed for phase, group and morphological analysis by x-ray diffraction (xrd), ftir, and esm/tem, respectively. the results have revealed a better understanding of how to synthesize pure calcium phosphates phases for the repair of bone defects using the cost-effective wet chemical process. small variation in the reactant molar ratio can significantly change the precipitated phases. controlling the reaction ph can governor effectively the precipitation of a specific phase despite of the small variation in the molar ratio.