Papers by Author: Hong Zhong

Abstract: This paper reports synthesis of hydroxyapatite nanoparticles by three precipitation methods. Homogeneous aqueous solution of Ca(NO3)2 and H3PO4 was used as precursor solution, and NH3•H2O was precipitator. Calcium deficient hydroxyapatite nanorods were obtained by adding the precipitator into precursor solution, near stoichiometric hydroxyapatite nanoparticles were derived from adding precursor solution into the precipitator, and smaller hydroxyapatite nanoparticles were prepared by adding precipitator and precursor solution simultaneously into a reaction vessel. The stoichiometry of hydroxyapatite was mainly affected by pH at precipitation reaction process. The crystal size and shape of hydroxyapatite particles was related to Ostwald ripening. The stoichiometry and morphology of hydroxyapatite nanoparticles can be controllable by selecting suitable coprecipitation process.

Abstract: This paper presents a typical coprecipitation method to synthesize silicate-substituted calcium deficient hydroxyapatite (SiCDHA). A homogeneous aqueous solution of Ca(NO3)2• 4H2O, H3PO4 and Si(CH3CH2O)4 (TEOS) was used as precursor, and NH3 aqueous solution as precipitator. A series of samples were prepared by adding the precipitator to the precursor then following a general coprecipitation route. The results showed that the so-prepared samples were SiCDHA. SiCDHA was thermal unstable and decomposed to tricalcium phosphate and wollastonite-like phase. These new phases were helpful to improve the bioactivity of sintered SiCDHA ceramics.