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Bioactivity of Surface Modified Titanium Alloy Ti-6Al-4V ELI by Pack Siliconizing in Simulated Body Fluid

Rezvani, Alireza | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39151 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Enginnering
  6. Advisor(s): Ekrami, Ali Akbar; Ziaei Moayyed, Ali Akbar
  7. Abstract:
  8. Titanium alloy Ti-6Al-4V ELI with high biocompatibility and corrosion resistance, has a lot of applications in biomedical engineering. Disadvantage of this alloy is it’s disability to create a fast and good contact with the host/bone environment, after implanting in the body. Beside that it has low wear resistance. Nowadays to optimize the wear resistance, bioactivity and osteoconduction of surface of implants which are made from this alloy, the surface morphology are optimized in size and distribution. Different surface treatments are used for producing rough and porous surfaces to improve bioactivity along with wear resistance. In this study, surface modification of Ti-6Al-4V ELI was done via Pack Siliconizing treatment in temperatures between 1000-1200oC for 3 hours at the presence of silicon powder. It was demonstrated that siliconized surfaces had higher roughness, hardness and wear resistance than the substrate alloy. SEM, EDS and XRD surface characterization showed that surface phases were Ti3Si, Ti5Si3 and TiSi2. Activation energy for growth of silicide layers was measured about 392 KJ/mol. For evaluating bioactivity, siliconized samples as well as control sample were soaked in simulated body fluid (SBF) for 28 days. SEM study of modified surface showed that the surface was covered with uniform spherical aggregates of calcium phosphates in the samples for different siliconizng conditions. For sample which was siliconized at 3h-1000oC condition, no uniform calcium phosphate precipitates was observed while for the other two conditions of 3h-1100oC and 3h-1200oC, SEM and XRD studies showed that precipitates of calcium phosphates and mainly bone-like apatite were formed. Results of this study showed that surface modification by pack siliconizing has the ability to improve bioactivity, hardness and wear resistance of titanium alloy Ti-6Al-4V ELI. In addition, mechanisms for such improvements were proposed
  9. Keywords:
  10. Titanium Alloy ; Wear Resistance ; Titanium Alloy 6AL-4V ; Simulated Body Fluid (SBF) ; Metallic Implants ; Bioactivity

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