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Preparation and Characterization of Nanostructural Ternary Mixed Oxide Containing Ti/Ru/Ir on Titanium by Sol-gel Process for MMO Electrode

Goudarzi, Mona | 2014

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 46714 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Ghorbani, Mohammad
  7. Abstract:
  8. In this study, ternary metal oxide coating consisting of Ti, Ru, Ir were prepared by sol-gel method. In order to achieve optimal conditions, the effect of number of layers, temperature and velocity of the heat treatment, the amount of ruthenium and iridium, polymeric additive on the coating and also, comparisons of binary and ternary oxide coatings were studied. The corrosion behavior was examined by anodic polarization and cyclic voltammetry tests and accelerated stability test (AST), the morphology of coatings was studied by field emission scanning electron microscopy (FESEM), phase and elemental analysis was performed using X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS), respectively.
    The results showed that thickness of one layer was 300 nm and cracks with a width of 80-900 nm were developed in all coatings during the heat treatment. By comparing the morphology and surface topography in the number of different layers, it was observed that the distribution of cracks in the coating with six layers with temperature of 450 ˚C and velocity of 5 ˚C/min was more uniform. Also, the most surface fraction of crack (%18.4±4) and the crack average width of 848±48 nm were observed in the coating with six layers. It was also observed that in a solution containing high concentrations of chloride, chlorine gas emission reaction takes place in a potential lower (0.750 V) and less slope (0.167 V/decade). Because of the presence of iridium in ternary coating, its structure is more porous than binary coating and has got more surface. Also ternary coating is more active in low overpotentials. Released gases however fill in cavities in high overpotentials which leads to lower capability of transferring load at the coating surface. Therefore ternary coating is more active in low overpotentials and more prone to load transferring disability in high overpotentials because of its more porous structure
  9. Keywords:
  10. Titanium ; Sol-Gel Method ; Nanostructure ; Mixed Metal Oxide ; Ternary Mixed Oxide ; Titanium/Ruthenium/Iridium Metal Oxide

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