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Innovation of guide rail production technology
Zlínská, Marie ; Ohnišťová, Petra (referee) ; Píška, Miroslav (advisor)
This bachelor's thesis provides the new plan of technological process of production of the guide rail used on the splitting machine type SVIT 06155. The current process of component production, which was designed more than 40 years ago, is proving inefficient with regard to current production possibilities. The first part of the work describes the process of splitting the leather, further explains the principle of operation of the machine and then defines the required properties of the guide rail in terms of operating conditions. The analysis of the issue reveals two possible solutions. The first is a change of the material of the guide rail and the second is a change of the coating technology and its composition. The introduction of the experimental part presents the solution, together with the newly designed production process and drawing documentation of the guide rail. The correctness of the design is further verified by the production of the component itself and by the evaluation of the surface condition of the Alicona device using the surface and profile method. Finally, an evaluation is made and recommendations for future production of the component are discussed.
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Preparation and characterisation of coatings for controlled-release fertilizers
Jašek, Vojtěch ; Sedláček, Petr (referee) ; Figalla, Silvestr (advisor)
The literary research of this Master's thesis is dedicated to controlled-release fertilizers (CRF). There is written the description of particular representatives of this kind of fertilizer and it also contains principles of nutrition's release mechanisms. Theoretical part is mainly focused on coated fertilizers, materials used for their production, coating technological processes and on a mathematical description of the diffusion transport which is the key of the mass transfer through polymer coatings. The laboratory preparation of innovative coatings based on modified vegetable oils is the main part of the experimental part of the thesis. It consists of the precursors' synthesis which can be applied on the fertilizer's surface in a liquid phase and polymerized by the UV-radiation in combination with an appropriate photoinitiator. There is described the synthesis of additional modifiers of precursors' viscosity and coatings' diffusive properties based on bio-source reactants such as sorbitol or ethyl lactate. The synthesized products are characterized by various methods such as volumetry, FTIR method or viscosimetry. The last part of the thesis contains the description of diffusive characteristics of coatings prepared out of the synthesized precursors.
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Design of material for drawing tools
Petrecký, Adam ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
Bachelor thesis deals with optimalization of material choice and its heat treatment for cold work forming tools. The thesis deals with specific failure of seizure during the cold forming of high strenght steel for automotive. First part deals with theory of cold forming and tool steels made for this purpose. The main goal of the thesis was to discover cause of the failure and deduce solution as choice of alternative material with its proper heat treatment and surface coating. Solution has to show higher lifespan and also has to deliver economical benefit.
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Porous-alumina-assisted formation of metal and metal-oxide nanostructures for use in advanced micro-devices
Kamnev, Kirill ; Mardare, Andrei Ionut (referee) ; Blanchar, Xavier Correig (referee) ; Mozalev, Alexander (advisor)
Anodizace kovů přes masku porézní anodické aluminy (PAA) je použita namísto nanoporézní anodizace nebo tradičních nanofabrikačních metod na výrobu nových nanostrukturovaných oxidů kovů se zdokonalenými parametry. Vylepšování vlastností oxidů ZrO2 a HfO2 nanostrukturováním vzbuzuje podstatný zájem kvůli aktivní komercionalizaci těchto oxidů kovů. Nanostrukturování ZrO2 a HfO2 anodizací je náročné kvůli včasné krystalizaci anodického oxidu a téměř nulovému transportnímu číslu kationtů. Tyto problémy jsou řešeny systematickým zkoumáním anodického chování dvouvrstev složených z tenké vrstvy Al nadeponované na vrstvě Zr nebo Hf. Po prvý krát je dosažen reprodukovatelný růst ZrO2 nanostruktur přes masku PAA, které plní póry PAA masky jenom částečně. Tyto vnořené ZrO2 nanostruktury se projevují zlepšeným dielektrickým výkonem v širokém rozsahu frekvencí s nízkými zbytkovými proudy a vysokými hodnotami průrazného napětí. Tyto vlastnosti z nich dělají atraktivní struktury pro použití v mokrých a hybridních elektrolytických kondenzátorech. Vrstvy s rovným povrchem, kompatibilní se standardními metodami nanofabrikace a obsahující ZrO2 nanostruktury kompletně plnící póry PAA masky, jsou syntetizovány kombinací anodizace přes masku PAA s částečným rozpuštěním PAA. Tyto vrstvy jsou použity v experimentálních MIM mikrokondenzátorech, které vykazují nízké zbytkové proudy, vysoké hodnoty průrazného napětí, vysoké hustoty energie, nízké hodnoty teplotního koeficientu kapacity a výbornou linearitu mezi kapacitou a napětím, což z nich dělá dokonalé kandidáty pro pasivní integraci zařízení na čipu. ZrO2 nanovrstvy připraveny anodizací přes masku PAA jsou, po prvý krát, schváleny k produkci osteogenních biokeramických povlaků. Tyto nanostrukturované biokeramické ZrO2 povlaky mohou modulovat interakce mezi buňkami a povrchem a zvyšovat mineralizaci osteoblastů 5 krát oproti rovné anodické ZrO2 vrstvě. Nanostrukturované HfO2 vrstvy připraveny anodizací přes masku PAA vykazují opakovatelné nízkovýkonové bipolární rezistivní spínání, což je dělá význačnými jako tuhé elektrolyty pro aplikace v memristorech. Anodizace Hf přes masku PAA v kombinaci s vhodnými chemickými modifikacemi povrchů je použita po prvý krát k vytvoření samouspořádaných nanostrukturovaných HfO2 povlaků, které jsou superhydrofóbní, odpuzují olej, jsou transparentní pro viditelné světlo a antireflexní, což je dělá velmi vhodnými pro pasivaci fotovoltaických zařízení.
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The role of thermal spray parameters on structure and properties of cermet coatings
Vražina, Tomáš ; Čelko,, Ladislav (referee) ; Šulák, Ivo (advisor)
The diploma thesis investigates the influence of thermal spray process parameters on the properties of composite coatings, specifically WC-CrC-Ni and WC-Co-Cr coatings deposed onto an austenitic steel substrate. The main objectives were characterization of sprayed deposition and creation of process maps. The theoretical part included the most important details about the manufacturing process, properties, consolidation and application of cermet materials. The methodical part is devoted to a description of analytical methods and devices used for the characterization of coatings microstructure and its mechanical properties. The practical part provides information acquired from analytical devices. It contains details about surface roughness, hardness, porosity, indentation modulus, corrosion potential and corrosion current density. The chemical composition of coatings and powder mixtures was analyzed by energy dispersive spectroscopy (EDS). For more accurate determination of developed phases X-ray diffraction was used. During the coatings characterization various procedures were developed. It is expected that these procedures would be implemented in another optimization of spraying conditions. Results obtained in the practical part were discussed in discussion and compared with the results from several research studies. Conclusions summarize results obtained in practical part.
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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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Production of threads with taps
Juránek, Martin ; Dvořák, Jaromír (referee) ; Píška, Miroslav (advisor)
This Bachelor thesis deals with the issue of production threads with taps. The introduction of th work briefly describes the use of thread in machine-building, thread geometry and basic types of threads. The work goes on to describe the methods tapping and thread control function. The work also deals with the description of types of taps, tool materials and the description of the three most used types of coating in taps. The experimental part adresses the question of whether the thicker layerof the TiN coat leads to an extension of the tool life. Two types of taps were used in the experiment. One type of taps had a coating thickness of 3-4 m and the other had coating thickness of 5-6 m. The experiment included measuring of time-dependent torque. The measured data were processed and subsequently evaluated whether the thicker coating layer resulted in reduced tool wear and increased tool life.
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Surface coatings of medium and high entropy alloy prepared by the cold-spray method
Vražina, Tomáš ; Adam, Ondřej (referee) ; Moravčík, Igor (advisor)
This bachelor thesis investigated coating of the CoCrNi (Medium entropy) alloy deposed onto austenitic steel substrate. The main objectives were characterization and analysis of sprayed deposition before and after heat treatment. The thesis was divided into 2 main parts. The theoretical part provided general information about alloy manufacturing, properties, and the method of its consolidation. The experimental part provided electron microscopy analysis including, an EDS, a porosity analysis and microhardness testing. Its results were then discussed on the base of the information gathered in the theoretical part. The results showed that the deposed layer was stable and there was no sign of material decohesion. The coating showed low porosity which was later successfully lowered by heat treatment. EDS proved that the coating was not entirely homogenous. The conclusion summarized the results achieved in the practical part.
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Innovation of guide rail production technology
Zlínská, Marie ; Ohnišťová, Petra (referee) ; Píška, Miroslav (advisor)
This bachelor's thesis provides the new plan of technological process of production of the guide rail used on the splitting machine type SVIT 06155. The current process of component production, which was designed more than 40 years ago, is proving inefficient with regard to current production possibilities. The first part of the work describes the process of splitting the leather, further explains the principle of operation of the machine and then defines the required properties of the guide rail in terms of operating conditions. The analysis of the issue reveals two possible solutions. The first is a change of the material of the guide rail and the second is a change of the coating technology and its composition. The introduction of the experimental part presents the solution, together with the newly designed production process and drawing documentation of the guide rail. The correctness of the design is further verified by the production of the component itself and by the evaluation of the surface condition of the Alicona device using the surface and profile method. Finally, an evaluation is made and recommendations for future production of the component are discussed.
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