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Elastic characteristics of coatings
Olivo, Tomas ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
The thesis focuses on the determination of Young's modulus of elasticity in tension of coatings with the inclusion of the effect of porosity using the impulse excitation method (IEM). In the theoretical part, the basics of the impulse excitation method and nanoindentation are discussed. Subsequently, the types of composite materials are presented, followed by a description of the Cold Spray technology used to produce the coatings presented in this work. In the next section, the composite models used to evaluate the measured data are defined. The experimental part is devoted to the description of the preparation of the test specimens, i.e., the substrate-coating system, together with the nanoindentation and pulsed excitation test procedure. Based on these tests, the tensile elastic moduli of the deposited coatings were evaluated using four composite models and compared with the results from the nanoindentation test. The most appropriate of these models was found to be the one based on the rule of mixtures with the inclusion of the nonlinear effect of porosity.
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Determination of mechanical characteristics of coatings using impulse excitation technique
Valášek, Daniel ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
This diploma thesis deals with the determination of the Young’s modulus of coatings using the impulse excitation technique (IET). The theoretical part of the thesis describes Cold and Thermal Spray technology, theoretical foundations of the impulse excitation technique and models of composite materials. The experimental part of the thesis deals with the determination of the tensile modulus of copper coating created by Cold Spray technology. The impulse excitation technique has been used to measure fifteen samples with coating thickness ranging approximately from 0,4 to 2 mm. Results from this measurement were evaluated using five composite models to establish the Young’s modulus of the applied coating. The best results were achieved by using the composite model based on rule of mixtures (ROM).
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Determination of mechanical characteristics of coatings using impulse excitation technique
Valášek, Daniel ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
This diploma thesis deals with the determination of the Young’s modulus of coatings using the impulse excitation technique (IET). The theoretical part of the thesis describes Cold and Thermal Spray technology, theoretical foundations of the impulse excitation technique and models of composite materials. The experimental part of the thesis deals with the determination of the tensile modulus of copper coating created by Cold Spray technology. The impulse excitation technique has been used to measure fifteen samples with coating thickness ranging approximately from 0,4 to 2 mm. Results from this measurement were evaluated using five composite models to establish the Young’s modulus of the applied coating. The best results were achieved by using the composite model based on rule of mixtures (ROM).
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