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Advanced hydrophobic and hydrophilic surface treatments for non-nuclear energetics
Komarov, Pavel ; Ctibor,, Pavel (oponent) ; Pawlowski, Lech (oponent) ; Čelko, Ladislav (vedoucí práce)
Particular interest is given to solid surfaces with specific wetting behavior (hydrophilic/superhydrophilic and hydrophobic/superhydrophobic) due to their wide range of potential applications such as drag-reducing, anti-icing/de-icing, corrosion-resistant, anti-biofouling, self-cleaning, etc. surfaces. However, the production ways of such coatings are sophisticated multi-step procedures, which are expensive and do not provide sufficient robustness of the hydrophilic/hydrophobic wetting behavior. The doctoral thesis is focused on (i) the development of a technological way to fabricate hydrophilic/hydrophobic coatings from wear-resistant materials utilizing thermal spraying technology; (ii) a detailed investigation of deposited coatings, analysis of their mechanical properties and the robustness of their wetting behavior. The first part of the thesis represents a theoretical background on the wetting behavior, surface free energy, hydrophilic/superhydrophilic and hydrophobic/superhydrophobic coatings and thermal spraying technology. In the second part, Al2O3, Cr2O3-SiO2-TiO2, YSZ and WC-Co-Cr plasma-sprayed coatings were fabricated, and their wetting behavior was analyzed concerning their surface topography. Furtherly, several YSZ coatings with lamellar and columnar microstructures were studied to investigate the role of the microstructure on their wetting behavior. The effect of RF-plasma jet surface treatment is also presented. Finally, three different powder feedstocks of WC-Co-Cr were utilized to fabricate wear-resistant coatings with the so-called multi-scale surface topography. It was found that the combination of a coarse powder with ultra-fine (~500 nm) WC particles provides an optimal surface topography with a very high hydrophobicity that furtherly can be tuned into the superhydrophobic state after the additional Si-oil treatment. In the last part, the robustness of the wetting behavior of WC-Co-Cr samples was estimated by the slurry abrasion response test and the cavitation erosion resistance test.
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Advanced hydrophobic and hydrophilic surface treatments for non-nuclear energetics
Komarov, Pavel ; Ctibor,, Pavel (oponent) ; Pawlowski, Lech (oponent) ; Čelko, Ladislav (vedoucí práce)
Particular interest is given to solid surfaces with specific wetting behavior (hydrophilic/superhydrophilic and hydrophobic/superhydrophobic) due to their wide range of potential applications such as drag-reducing, anti-icing/de-icing, corrosion-resistant, anti-biofouling, self-cleaning, etc. surfaces. However, the production ways of such coatings are sophisticated multi-step procedures, which are expensive and do not provide sufficient robustness of the hydrophilic/hydrophobic wetting behavior. The doctoral thesis is focused on (i) the development of a technological way to fabricate hydrophilic/hydrophobic coatings from wear-resistant materials utilizing thermal spraying technology; (ii) a detailed investigation of deposited coatings, analysis of their mechanical properties and the robustness of their wetting behavior. The first part of the thesis represents a theoretical background on the wetting behavior, surface free energy, hydrophilic/superhydrophilic and hydrophobic/superhydrophobic coatings and thermal spraying technology. In the second part, Al2O3, Cr2O3-SiO2-TiO2, YSZ and WC-Co-Cr plasma-sprayed coatings were fabricated, and their wetting behavior was analyzed concerning their surface topography. Furtherly, several YSZ coatings with lamellar and columnar microstructures were studied to investigate the role of the microstructure on their wetting behavior. The effect of RF-plasma jet surface treatment is also presented. Finally, three different powder feedstocks of WC-Co-Cr were utilized to fabricate wear-resistant coatings with the so-called multi-scale surface topography. It was found that the combination of a coarse powder with ultra-fine (~500 nm) WC particles provides an optimal surface topography with a very high hydrophobicity that furtherly can be tuned into the superhydrophobic state after the additional Si-oil treatment. In the last part, the robustness of the wetting behavior of WC-Co-Cr samples was estimated by the slurry abrasion response test and the cavitation erosion resistance test.
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