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In order to obtain a fast biomimetic coating on titanium substrates, calcium enriched silica films were prepared on pure titanium substrates by sol-gel method under the following conditions: pH = 3 and the molar ratio of tetraethyl orthosilicate (TEOS)/H2O/EtOH/Ca2+ = 1∶4∶11∶0·08. The titanium base calcium enriched silica film is soaked in a slightly supersaturated Ca/P solution, with the concentration of calcium ion and phosphate group being 1·5 times of that of simulated body fluid, for seven days, a uniform apatite layer is precipitated onto the surfaces of calcium enriched silica films, which is quite rapidly. The investigation adopted SEM, EDX, Fourier transform infrared spectroscope and XRD to indicate that the coating was carbonate hydroxyapatite. The results show that it is a feasible way to obtain carbonate hydroxyapatite through functionalising the pure titanium substrates by preparing calcium enriched silica films on it from a sol-gel method. [ABSTRACT FROM AUTHOR]

Needle-like nanocarbonated hydroxyapatite (CHA) powders were prepared by hydrothermal method using Ca(NO3)2, (NH4)3PO4 and urea as reagents. Element analyse (EMA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetry differential thermogravimetry (TG-DTA) were used to characterise the crystalline phase, microstructure, chemical composition, morphology and thermal stability of CHA. The results show that AB type CHA can be obtained through this method. The carbonate content and the ratio of length to diameter of CHA can be adjusted by controlling the concentration of urea. The results show that CO32-incorporated into the apatite structure has an influence on the properties of CHA, such as the morphology and the size of crystal grain, the lattice parameters and the unit cell volume and the crystallisation degree and the stability. [ABSTRACT FROM AUTHOR]

Spherical nano-hydroxyapatite (HA) was synthesised successfully. Ca(NO3)24H2O and (NH4)3PO43H2O were used as reagents and polyvinylpyrrolidone (PVP) as template. The crystal phase, chemical composition, microstructure of the obtained HA were characterised by X-ray powder diffraction analysis, Fourier transform infrared spectroscopy, X-ray fluorescence spectrometry, thermogravimetric analysers microcomputer differential thermal analysers and transmission electron microscopy. The results show that the concentration of PVP significantly affects the morphologies of the nanometre HA. Spherical nano-hydroxyapatite particle with diameter of 30–50 nm can be synthesised using PVP of a certain concentration (05–5%) as template. The crystallinity of HA decreases continuously as the PVP content increases. Spherical apatite crystal forms because of a high affinity between HA and PVP. [ABSTRACT FROM AUTHOR]

Based on the principles of biomineralisation, spindle shaped hydroxyapatites (HA) were synthesised through the biomimetic method with chitosan (CS) as template. The microstructure, chemical composition and thermal behaviour were characterised by means of X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and thermogravimetry differential thermal analysis (TGDTA) respectively. The results show that the spindle shaped nanoHA, 30–40 nm in length and 7–8 nm in width, were synthesised with 0·5 wt-%CS as template in 6% (v/v) hydrogen peroxide solution for 7 days. The crystallinity of samples increased with the aging time. TGDTA analyses show that the HA powders synthesised with CS as template contain CS molecules and have good thermal stability up to 800°C. [ABSTRACT FROM AUTHOR]