Synthesis and Phase Transformation of Calcium Phosphate Prepared from Chicken Eggshells and Ammonium Phosphate
Material that shows hydroxyapatite and β-tricalcium phosphate phases is called biphasic calcium phosphate (BCP). In present work, biphasic calcium phosphate was prepared and characterized for future applications on the utilization of bioactivity of HAp and resorbability of β-TCP properties. It was simply synthesized by precipitation method using eggshell as the calcium source (Ca) in the form of calcium nitrate and ammonium phosphate as the phosphate source (P) to obtain biphasic calcium phosphate. The prepared BCP powders and crystal structure were characterized by X-ray diffraction (XRD), Rietveld refinements and Fourier transform infrared (FT–IR) techniques. The results indicate that BCP was observed at the calcining temperature of 800 oC and above. Furthermore, the crystallinity of BCP increases with increasing temperature from 800 - 1200 oC. The phase fraction of β-TCP is enhanced with pH of a solution from 8.6-10.6 and decrease with the temperature range of 800 - 1200 oC. The formation of BCP arises from its non-stoichiometric composition of materials such as variation of synthesis parameters.
P. Pankaew et al., "Synthesis and Phase Transformation of Calcium Phosphate Prepared from Chicken Eggshells and Ammonium Phosphate", Advanced Materials Research, Vol. 214, pp. 182-186, 2011