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Influence of pyrrolidone derivates on alkyd and polyurethane coatings.
Klímová, Edita ; Molliková, Eva (referee) ; Tulka, Jaromír (advisor)
The aim of this thesis was to append data on chemical resistance of coatings made of paints based on alkyd and polyurethane resins. In the theoretical part, relevant information on coatings, preparation of their systems, theory of solubilization and properties of solvents were collected and organized. Three N-derivates of pyrrolidone were chosen for the practical part. Their influence on particular alkyd and polyurethane coatings was studied with emphasis on time course of coatings degradation.
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Thermal Coatings for Glass Industry
Chráska, Pavel ; Neufuss, Karel
A new type of plasma torch with combined stabilization of electric arc by water vortex and gas flow is presented. This hybrid water/gas stabilization offers the possibility of adjusting plasma jet parameters within a wide range from high-enthalpy low-density plasmas typical for liquid stabilized torches to lower enthalpy higher density plasmas generated in gas stabilized torches. Moreover, gas flow in the cathode part protects a cathode tip and thus a consumable graphite cathode used in water-only stabilized plasma torches could be replaced by a fixed tungsten cathode. Examples of hybrid WSP torch utilization for high temperature application are given.
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Testování odolnosti vůči nárazu tvrdých nanokompozitních povlaků
Fořt, Tomáš ; Sobota, Jaroslav ; Grossman, Jan
To evaluate the impact resistance of hard nanocomposite coatings in dynamic loading wear applications an impact test using system developed at the Institute of Scientific Instruments in collaboration with Brno University of Technology has been used. During testing the specimen is cyclically loaded by a ball that impacts of the coating surface. After the test, wear scars were evaluated by means of scanning electron microscope, spectral analyses and profilometer. The impact test offers an important new method for determination of the fracture toughness of hard thin coatings and simulates a wide range of tribological systems.
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Plazmové stříkání nanokeramiky - oxidu hlinitého a zirkoničitého
Chráska, Tomáš ; Neufuss, Karel ; Nohava, Jiří ; Dubský, Jiří
A novel material has been plasma sprayed by water stabilized plasma torch (WSP®) in order to achieve nanocrystalline microstructure. The new material is composed of three main compounds, namely corundum (alpha Al2O3), baddeleyite (monoclinic ZrO2), and glassy phase (SiO2). The ratio of Al2O3 – ZrO2 compounds is close to that of their respective eutectic alloy. Both dense coatings and free standing parts were produced with the new material, which sprays very well by WSP®. Spraying parameters were varied and molten particles were monitored in flight. The coatings exhibit very low porosity and high hardness. The as-sprayed material is mostly amorphous with some nanocrystalline grains of aluminum and zirconium oxide present. The microstructure of the newly sprayed material was studied by electron microscopy (SEM, TEM) and was found to be very complex. Upon annealing, the as-sprayed material fully crystallizes at around 950ºC. Selected mechanical properties were measured as well.
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Mechanical properties of organic - inorganic nanocomposites coatings
Farkačová, T. ; Bláhová, O. ; Špírková, Milena
The contribution deals with the determination of tribological properties of hybrid organic-inorganic epoxy-based coatings on tribometer by method pin-on-disc. The friction coeffiecient and wear resistance were monitored. Examined specimens were prepared from functionalized organosilicon precursors, oligomeric di- or triamines and colloidal silica particles. The products are the result of two independent reaction mechanisms: the sol-gel process and the epoxy-amine addition reactions.
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