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Coating Nano Composite HAp-Al2O3-TiO2 on Stainless Steel 316 by Sol-Gel Method

Ahmadi, Reza | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53206 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Afshar, Abdollah
  7. Abstract:
  8. 316L stainless steel is used in implants under load in orthopedics and dentistry due to its high strength and corrosion resistance. Therefore, to improve their biocompatibility properties, bioceramic coatings with more suitable biocompatibility properties are used. Therefore, in the present study, to improve the biocompatibility and corrosion properties on 316 L metal implants, HAp / TiO2 / Al2O3 nanocomposite coating was created using the cost-effective sol-gel method. Titanium + alumina by weight percentage in these coatings were 20, 30, and 40% by weight. In this study, FTIR, XRD, DSC / TG, FE-SEM EDS, DLS tests were performed to investigate the chemical bases in nanocomposites, phase changes, thermal stability and to confirm the presence of hydroxyapatite, point analysis (elements in powder samples and Calcium to phosphorus ratio (hydroxyapatite) and particle size were used in powder samples. Pull Off test, light microscope, atomic force microscope, scanning electron microscope, polarization and electrochemical impedance spectroscopy, AES, and ICP were used to examine the properties of the coatings. Corrosion tests were performed on the simulated body solution. Also, for biocompatibility tests, different samples were immersed in the SBF solution for 28 days, and the amount of Calcium and phosphate in the solution and on the surface were investigated. MTT test was also performed to evaluate the viability of human MG63 cells exposed to different coatings. The results of this study showed that HAp + 30% wt (TiO2 + Al2O3) and HAp + 40% wt (TiO2 + Al2O3) samples had improved adhesion strength properties (23 and 26.5 MPa, respectively), higher corrosion properties (with current density). Corrosion (0.137 and µA / cm 20.091), no cracks, higher biocompatibility. However, increasing the weight percent to 40% of titania + alumina reduces the biocompatibility of the coatings (cell viability 82.5%). Therefore, the addition of titania + alumina has an optimal value, and the most optimal coverage is for the sample HAp + 30% wt (TiO2 + Al2O3) (99.5% cell viability)
  9. Keywords:
  10. Biocompatibility ; Corrosion Resistance ; Nanohydroxyapatite Coathing ; Adhesion Strength ; Sol-Gel Method ; 316 Austenitic Stainless Steel

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