| Fluoridated hydroxyapatite in whose structure F" occupies partially the position of OH" in hydroxyapatite (HA), is more resistant to body fluid and less soluble than hydroxyapatite, meanwhile, fluoridated hydroxyapatite (FHA) still possesses almost the same bioactiviry as HA. In this work, FHA films on glass and Ti6A14V substrates were prepared by sol-gel dip-coating method using hexafluorophosphoric acid (HPFe) as a fluorine-introducing reagent. Different amounts of HPF6 were added into the mixed ethanol solutions of Ca(NO3)2and P2Os, keeping the Ca/P ratio of 1.67. The mixtures with HPF^ were refluxed to be used as dipping liquid. As-dipped films on glass and titanium alloy substrates were heated at 500癈~600癈, FHA films could be formed. The films were characterized by X-ray diffraction, scanning electron microscopy, infrared reflection spectroscopy and x-ray photoelectron spectroscopy. With an increase in HPFe/Ca ratios, the fluorine contents of the films increased based on the XPS data, HPFe was shown to be a very effective reagent for incorporating fluorine into apatite. The SEM photos showed the morphology of the films depended on HPFe/Ca ratios in dipping liquid, the morphology changed from having cracks, small holes to having relatively large holes with an increase in the HPFe/Ca ratios in the dipping liquid.The films were soaked in simulated solutions to evaluate their biological behaviors, the results showed that the FHA film had a good bioactivity hi a simulated body fluid because nano apatite crystallinites were formed on the films; the FFIA films was less soluble than HA film in a citric acid modified phosphate buffer solution.The adhesion strength measurement of the films by push-out test showed that the adhesion strength of the FHA film was higher than that of the HA film. This work will make a significant contribution to the preparation of apatite coated titanium alloy implants with highly activity and long-term effectiveness.
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