| Hydroxyapatite (HA) is widely used in fields of biomaterials, biotechnology, and functional materials, due to its special component, structure and properties, especially the good biocompatibility based on its similarity to inorganic component of bone.In the researches on preparation methods of HA, nano hydroxyapatite (nHA) is emphasized and highlighted since 1980's. People have synthesized rod-like and needle-like HA crystals with nano size. Such nano crystals provide excellent properties and special functions for both bioceramics and composite biomaterials. In this study, sodium phosphate and calcium nitrate were used as reagents, and NaOH was used for adjusting pH value, nano-hydroxyapatite was prepared in water media, without any solvent or dispersant. Nano-hydoxyapatite prepared in this method performed similar dimensions, morphology, compositions and crystallinity. Change the adding order of reagents, the pH value of precipitates and reagents were study in this thesis also. The results indicated that adding P into Ca could obtained purer hydroxapatite and better crystallinity compared with opposite order. The alkaline condition of the precipitates and reagents could increase the purity and integrity of the hydroxyapatite too. The mechanism of the phenomena that adding P into Ca was better than the opposite order was also investigated in this thesis.The dissolution properties of the HA serum and powders after sintered were also be investigated in slight acid and alkaline surroundings and non-ion water. The... |
PDF Full Text Request