| HA(Hydroxyapatite) is an alkaline calcium salt with slight solubility in the water. HA can be used as bioceramics, the reinforcement of biopolymer, the film of biometals, and medicine carrier due to its good biocompatibility and bioactivity, revealing its significant role in the field of biology medicine. And the biological and mechanical properties of HA depend on its morphology, crystal size, and composition. As my knowledge, little detail research on the effect of hydrothermal procedure on the structure and property of HA has been carried out. So in this thesis, the relationship between hydrothermal parameters and the growth and structure of HA was investigated with the purpose of serving high quality HA biomaterials.In the experiment, calcium nitrate Ca(NO)3?4H2O and potassium hydrogen phosphate K2HPO4?3H2O were used as the source of calcium and phosphate. HA powder was prepared by hydrothermal method. The prepared HA samples were characterized by such techniques as X-ray powder diffraction (XRD), field emission scan electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) . The phases, composition, crystal size, crystallinity, thermal stability and lattice constants of the samples were found out in the varieties of pH values, pressure, carbonate-doping content, and magnesium-doping content.The results showed that:①As for the variety of pH value. The products were HA in our experimental conditions while adjusting the pH value from 5 to 10 in the initial reaction solution, which was needle-like or spherical and have a length of about 100~500nm.Hydroxyapatite on the morphology gradually changed from the needle to the spherical shape as the pH increases. The grain size of HA in the a-axis direction had a steady upward trend while basically the same aspect and slenderness ratio decreases in the c-axis direction.②Hydrothermal stress. It could get a certain percentage of HA which has the morphology of needle-like shape and had a length of about 50~300nm in the two different pressure levels as atmosphere of nitrogen and carbon dioxide gas. With the pressure increasing, the length of hydroxyapatite, slenderness ratio and crystallinity increased, andβ-tricalcium phosphate (β-TCP) content increase especially in carbon dioxide atmosphere because of the depressing of pH value.③Carbonate ion CO3-2. HA with carbonate ion of AB mixed was got in this experimental condition and had a slenderness ratio of 20~40. With the carbonate concentration increaseing, the crystallinity of hydroxyapatite whiskers increased. The size increased along the crystal C axis and slowed down when urea was more than 45%.④Magnesium ion Mg+2. HA with carbonate and magnesium ion was got in the experimental conditions with adding different amount of magnesium ion and urea. The grain had the morphology of whiskers or micro-spherical shape and its whiskers had a length of 8~70μm, a slenderness ratio of 5~20. The diameter of micro-spherical shape was 3~30μm and had a length of 2~5μm. Magnesium ions entered into the lattice. Mg induced MHA toβ-tricalcium phosphate in trend. With the concentration of magnesium and carbonate ions increasing, the grain size and crystallinity decreased and the formation of microspheres number increased. There was TCP phase when carbonate ion concentrations was comparatively low. |
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