Hydroxyapatite/titania (HA/TiO2) double layers were coated onto Ti scaffolds throughout for orthopaedic applications by sol-gel method. Differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and X-ray diffractometry (XRD) were used for the characterisation of the phase transformations of the dried gels and coated surface structures. Scanning electron microscope (SEM) equipped with energy dispersive spectrometry (EDS) was used for the observation and evaluation of the morphology and phases of the surface layers and for the assessment of the in vitro tests. The in vitro assessments were performed by soaking the HA/TiO2 double coated samples into the simulated body fluid (SBF) for various periods. The TiO2 dipping-coating method at a speed of 12 cm/min, followed by a heat treatment at 600 ℃ for 20 min. The HA la lyaeyre wr wasa ssu cbosaetqeude bnytl ya dipping-coated on the outer surface at the same speed and then heat-treated at difference temperatures. The results indicat that the HA phase begins to crystallize after a heat treatment at 560 ℃. The crystallinity increases obviously at 760 ℃. SEM observations find no delamination or crack at the interfaces of HA/TiO2 and TiO2/Ti. The HA/TiO2 coated Ti scaffolds displays excellent bone-like apatite forming ability when it is soaked into SBF. Ti scaffolds after HA/TiO2 double coatings can be anticipated as promising implant materials for orthopaedic
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