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Design and Manufacture of Nanostructured Hydroxyapatite coated Foamy core@compact Shell Ti-6Al-4V Nanocomposite

Ahmadi Seyedkhani, Shahab | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46858 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Sadrnezhad, Khatiboleslam
  7. Abstract:
  8. The main purpose of this research is design and manufacture of nanostructured hydroxyapatite-coated foamy core@compact shell Ti-6Al-4V bone-like composites for utilization as substitutive implant for cortical bone having porous core. The production procedure consist of two steps; (a) fabrication of foamy core@compact shell Ti-6Al-4V alloy using powder metallurgy-space holder technique, (b) precipitation of hydroxyapatite on the Ti-6Al-4V alloy specimens via pulse electrodeposition process. The bone-like structures were designed to reduce the stress shielding which ensures long-term stabilization of implants. It is while that, the hydroxyapatite coating improve the biological response of non-bioactive surface of Ti-6Al-4V alloy. Density, interconnected porosity and the mechanical properties of the prototypes were evaluated according to change of the porous core diameter. The results showed that similar mechanical behaviors as those of human bones were achieved by changing the porous core diameter. The surface modification included anodizing as intermediate treatment process to produce TiO2 nanotubes layer and electrodeposition of hydroxyapatite coating. X-ray diffraction and field emission electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS) analysis were applied to characterize the composition and microstructure of the coatings. Surface topography, Nanohardness, elastic modulus and scratch properties measured by atomic force microscope (AFM) equipped with nano-indenter. Electrochemical behavior of the samples measured through polarization and electrochemical impedance spectroscopy (EIS) tests in the simulated body fluid (SBF) at 37 ᵒC. In vitro tests were applied to evaluate of biological responses of each coating. For this reason, MTT, cytotoxicity and alizarin red staining tests were done to study of biocompatibility and mineralization of the implants respectively. Finally, FESEM was employed to survey of osteoblast cell adhesion on the surface of the implants
  9. Keywords:
  10. Anodizing ; Hydroxyapatite ; Polarization ; Scratch Rsistance ; In-Vitro ; Titanium Alloy 6AL-4V

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