Hydroxyapatite with needle-like shape has been successfully synthesized by reflux method with the aid of ultrasonic treatment and different dispersants. As-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscope. The effects of ultrasonic and dispersants on formation, composition and morphology of the products have been investigated in detail. It is shown that ultrasonic treatment is favorable for the rapid nucleation and growth of HA crystal and the selected dispersants contribute to form needle-like HA crystal. The formation mechanism has also been preliminarily explained.

The influence of different cosurfactants on morphology of nano-sized hydroxyapatite powder prepared in CTAB inverse microemulsion has been investigated.TEM,XRD and FT-IR are used to characterize the morphology and structure of the resulting samples.It is indicated that phase components and crystal structure of nano-HA are not distinctly affected by the increase of chain length of cosurfactant alcohol,but the particle size and morphology are obviously affected by it.It is found that interfacial film strength is closely related to the alcohol chain length.In particular,the chain length of octanol matches well with that of CTAB,so its interfacial film strength was highest,leading to the most number of micelles and prime dispersion for preparing nano-HA.The diameter of nano-HA powder is increase by the increase of chain length of cosurfactant alcohol.

The preparing process of hydroxyapatite using quick sol-gel method has been studied by orthogonal design method.The molar ratio of reactant,starting concentration,reacting temperature and sintering temperature that affect the Ca/P of the products were also detailedly investigated.Meanwhile,the contents of Ca and P in the result were analyzed by improved chemical analysis.It is shown that the high quality and fine crystal of HA could be successfully synthesized.As for the four factors,the molar ratio of reactants ratio is a prominent factor,and the sintering temperature is a less important factor to the final product.

Hydroxyapatite(HA) whisker,with lower dislocation density and higher tensile strength,can be used as toughening material in bioceramic.HA whisker has been synthesized under hydrothermal condition by controling reaction temperature and time,using Ca(NO3)2 ·4H2O and(NH4)2HPO4 as raw materials.The phases,morphology,size,and chemical composition of obtained products were characterized by X-ray diffraction(XRD),transmission electron microscope(TEM),and fourier transform infrared ray(FT-IR),respectively.The results showed that hydroxyapatite whiskers with high degree of crystallinity,uniform morphology,and with high slenderness ratio can be successfully synthesized by hydrothermal treatment with urea and sorbitol as addition agents,when n(Ca)/n(P) of precursors is 1.67.

Hydroxyapatite(HA) whisker could be used as toughening material in bioceramic.In this experiment,hydroxyapatite whiskers with high crystalline,uniform morphology and high aspect ratio can be successfully synthesized by the hydrothermal treatment at 110℃ and for 10h,using Ca(NO3)2.4H2O and(NH4)2HPO4 as precursor,distilled water as solvent,urea as pH adjusting agent,sorbitol(90%) and threonine(10%) as additives.The phases,chemical composition,morphology and size of obtained products were characterized by X-ray diffraction(XRD),Transmission electronic microscopy(TEM) and Fouier transform infrared spectroscopy(FT-IR) respectively.