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Hydroxy Apatite/Titania Nanostructure Biocoating on Ti-6Al-4V Alloy by Sol-Gel Dip-Coating

Dabir, Fatemeh | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40082 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Faghihi Sani, Mohammad Ali
  7. Abstract:
  8. Ceramic coatings on metallic substrates are used in many different applications. In biomaterials science, hydroxyapatite coating due to its similarity to the mineral part of bone structure is used to modification of implants surface. In this research, the HA/TiO2 double layer was coated on Ti-6Al-4V by sol- gel dip-coating method. After preparation of stable TiO2 sol, the Ti-6Al-4V substrate was dipped into the TiO2 sol. The speed of dipping was 10cm/min. After drying at 80°C, the TiO2 layer heat-treated at different temperature (350-500°C) for 1h. The HA outer layer was coated by dipping of Ti-6Al-4V substrate with TiO2 layer into HA sol, followed by heat-treatment at different temperatures (300-400°C) for 30 min. The speed of dipping was 5 cm/min. The optimum temperatures for calcination of TiO2 and HA coating was chosen 400°C and 350°C, respectively. Phase formation and the surface morphology of coatings have investigated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), Respectively. The corrosion test proved that by applying of the TiO2 and HA coatings, the corrosion resistance of Ti was improved. The pull-off test showed that with insertion of TiO2 buffer layer, the bonding strength of HA coating on Ti-6Al-4V substrate was increased. In order to evaluating of bioactivity, samples with TiO2 and HA/TiO2 coating was soaked in Simulated body Fluid (SBF) at 37°C for 3, 14 and 28 days. By SEM observations, the formation of calcium phosphate precipitations on the surface of coatings proved. Thin-film X- Ray Diffraction (TF-XRD) and EDS analysis showed the precipitations formed on surface of coatings were calcium phosphate phases. At equal periods of soaking of coatings into SBF, the precipitation formed on HA/TiO2 coatings in comparation with TiO2 coatings, were more, indicating the improvement of bioactivity of Ti implants with applying the HA coatings
  9. Keywords:
  10. Sol-Gel Method ; Titanium Alloy ; Bioactivity ; Titania ; Nanohydroxyapatite Coathing ; Simulated Body Fluid (SBF)

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