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Measurement of corrosion resistance of anodized aluminum protective surface layers
Redr, Martin ; Jandová, Kristýna (referee) ; Chladil, Ladislav (advisor)
This master’s thesis is focused on anodic oxidation of an aluminium surface with subsequent sealing of the surface using mid-temperature sealing methods. The research in the theoretical part of the thesis is carried out in surface treatments of aluminium and its alloys, where attention is mainly paid to anodic oxidation, as it is the most widely used surface treatment. The second discussed and at the same time key topic is the sealing process of the anodic coating, which has a fundamental effect on the quality of the corrosion resistance of the resulting surface. In the practical part of the thesis, a number of anodic oxidation experiments with subsequent sealing of the coating on prepared aluminium samples and their subsequent evaluation according to ČSN EN ISO 3210 standard were carried out. Mid-temperature sealing experiments were mainly focused on the use of triethanolamine (TEA), which seems very promising in terms of the resulting sealing quality.
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Fabrication of aluminium nano-templates by controlled dip anodizing
Stehlíček, Kamil ; Dvořák, Petr (referee) ; Lednický, Tomáš (advisor)
In this thesis we focus on the optimization of the technological process of making porous aluminium oxide (porous alumina), with emphasis on the level of orderliness of the final structure. Theoretical part is aimed primarily at the research part with overlap to defining the initial parameters values for experimental part. Experimental part is then focused on finding the optimal values of experimental parameters. Parallel task to the experimental part is the assembly of the laboratory setup used for anodization process.
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Research and development of a technology of hard anodization of nonferrous alloys
Remešová, Michaela ; Kudláček,, Jan (referee) ; Vidal, Salvador Pané (referee) ; Kaiser, Jozef (advisor)
Práce je zaměřena na výzkum a vývoj technologie přípravy tvrdých anodických vrstev na třech různých typech neželezných materiálů a to (i) hliníkové slitině (AA1050), (ii) čistém hořčíku (99.9% Mg) a (iii) zinkové slitině (ZnTi2). Vhodnou kombinací anodizačních podmínek (napětí, proudová hustota, teplota a složení elektrolytu atd.) lze vytvářet anodické vrstvy s rozdílnými vlastnostmi. V rámci předložené práce byl prokázán vliv předúpravy a anodizačních podmínek na vzhled, morfologii, tloušťku a tvrdost vytvořených anodických vrstev. Pro zvýšení tribologických vlastností a tvrdosti byly anodické vrstvy přímo dopovány Al2O3 částicemi nebo kombinací Al2O3 a PTFE částic během anodizačního procesu. Teoretická část práce popisuje základní principy anodizace, metody používané v průmyslové praxi a v práci je také popsán technologický proces. Experimentální část je rozdělena na tři základní části. První část se věnuje anodické oxidaci hliníkové slitiny AA1050. Druhá část je zaměřena na anodizaci čistého hořčíku a poslední část je zaměřena na anodizaci zinkové slitiny ZnTi2, která není tak známá jako anodizace hliníku.
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Reflex of Space
Šrom, Samuel ; František,, Dvořák (referee) ; Korbička, Pavel (advisor)
The diploma thesis named Reflections of Space aims to change the approach at material anodizing and to move this purely technological process to the artistic level. The first part of the thesis summarises concisely a process of anodising and seeks for its demonstrations in the field of culture. The second part of the thesis describes the intention itself and the results of the research in the framework of technological proofs which are presented in the figurative part of the thesis.
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Nanostructured sensors for detection of organic compounds
Šťávová, Karolína ; Fohlerová, Zdenka (referee) ; Hrdý, Radim (advisor)
This bachelor's thesis is focused on the fabrication of sensitive layers composed of an array of gold nanorods and their modifications. Firstly, a nanoporous mask is made from a layer of aluminum using a method called anodic oxidation. Afterwards electrochemical deposition of gold and polypyrrole or gold and mercury is carried out into the mask. The sensitive layer is characterized by the scanning electron microscopy and other methods for elemental analysis. A sensor with this type of sensitive layer can be used for the detection of various organic compounds.
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Gas Microsensors Based on Self-Organized 3D Metal-Oxide Nanofilms
Pytlíček, Zdeněk ; Husák, Miroslav (referee) ; Kolařík, Vladimír (referee) ; Prášek, Jan (advisor)
This dissertation concerns the development, fabrication and integration in a gas sensing microdevice of a novel 3-dimensional (3D) nanostructured metal-oxide semiconducting film that effectively merges the benefits of inorganic nanomaterials with the simplicity offered by non-lithographic electrochemistry-based preparation techniques. The film is synthesized via the porous-anodic-alumina-assisted anodizing of an Al/Nb metal bilayer sputter-deposited on a SiO2/Si substrate and is basically composed of a 200 nm thick NbO2 layer holding an array of upright-standing spatially separated Nb2O5 nanocolumns, being 50 nm wide, up to 900 nm long and of 8109 cm2 population density. The nanocolumns work as semiconducting nano-channels, whose resistivity is greatly impacted by the surface and interface reactions. Either Pt or Au patterned electrodes are prepared on the top of the nanocolumn array using an innovative sensor design realized by means of microfabrication technology or via a direct original point electrodeposition technique, followed by selective dissolution of the alumina overlayer. For gas-sensing tests the film is mounted on a standard TO-8 package using the wire-bonding technique. Electrical characterization of the 3D niobium-oxide nanofilm reveals asymmetric electron transport properties due to a Schottky barrier that forms at the Au/Nb2O5 or Pt/Nb2O5 interface. Effects of the active film morphology, structure and composition on the electrical and gas-sensing performance focusing on sensitivity, selectivity, detection limits and response/recovery rates are explored in experimental detection of hydrogen gas and ammonia. The fast and intensive response to H2 confirms the potential of the 3D niobium-oxide nanofilm as highly appropriate active layer for sensing application. A computer-aided microfluidics simulation of gas diffusion in the 3D nanofilm predicts a possibility to substantially improve the gas-sensing performance through the formation of a perforated top electrode, optimizing the film morphology, altering the crystal structure and by introducing certain innovations in the electrode design. Preliminary experiments show that a 3D nanofilm synthesized from an alternative Al/W metal bilayer is another promising candidate for advanced sensor applications. The techniques and materials employed in this work are advantageous for developing technically simple, cost-effective and environmentally friendly solutions for practical micro- and nanodevices, where the well-defined nano-channels for charge carriers and surface reactions may bring unprecedented benefits.
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Oxidation barriers prepared by electrochemical procedures
Šťastná, Eva ; Pouchlý, Václav (referee) ; Jan, Vít (advisor)
A process with aim to prepare an oxidically and thermal resistant layer was performed on the samples from clear aluminium (99,99+ %, VÚK čisté kovy, s. r. o.) and on the samples from clear titanium (99,95 % Goodfellow) with a layer from sputtered aluminium (99,99 %, VÚK čisté kovy, s. r. o.), An oxidic layer was prepared on the samples by anodization in the oxalic acid. The layer had fine, hexagonally organized pores with the diameter of 30 nm. During the following processing was the structure prepared for the electrochemical deposition of copper to the pores. The aim of the electrodeposition was preparation of copper nanowires deposited into the pores of the oxidic layer. The process was performed in the solution of copper sulfate and sulfuric acid in water. The controlling parameter of the deposition was voltage which had a very asymmetric period. The period had to be optimized for a successful preparation of the wires. The result of the whole process was structure with oxidic matrix whose most of the pores were filled with copper.
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Nanoelectrodes for biophysical measurements
Márik, Marian ; Hrdý, Radim (referee) ; Hubálek, Jaromír (advisor)
The aim of the project is formation of nanoelectrodes on the silicon wafer surface by thin-film techniques combined with lithography and nanotechniques developed in LabSensNano. Project is engaged in lithography and in preparation of silicon wafers. Furthermore is proposed a brief proposal of electrodes, proposal of realization and current state of the experiment.
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Technology of Galvanic Anodization of Non-ferrous Materials and Its Alloys
Remešová, Michaela ; Hadraba,, Hynek (referee) ; Čelko, Ladislav (advisor)
The thesis is focused on the theoretical description of the technology of anodizing of aluminium, magnesium, zinc and their alloys. In this work, methods for formation of oxide layers and the used chemical processes are described in detail. The experimental part of this work deals with formation of oxide layers on aluminium, magnesium and zinc of high purity under different conditions. Oxide layers of different thicknesses were created on all three experimental materials. Aluminium was anodized in a bath of 10% H2SO4, magnesium in the bath of 1 mol/dm3 NaOH, and zinc in the bath of 0.5 mol/dm3 NaOH. Processes were carried out at laboratory temperature. On the aluminium, continuous oxide layer was formed. Furthermore rule "312" was verified, that can indicatively be used for calculating the thickness of the resulting oxide layer on the aluminium. When using lower current of 0.08 and 0.2 A for magnesium anodizing, dark colored layer was created comparing to higher current of 0.5 A. More rough appearance of the oxide layer was produced with increasing voltage. Further, it was observed for magnesium that the resulting layer comprises of two sublayers. For zinc, black colored layer was created when the voltage 20 V and current from 0.4 to 0.5 A were used. In the layer, two sublayers were also observed. For lower voltage and current (0.05 A, 0.17 V), formation of the oxide layer on the zinc does not occur, but the crystallographic etching was observed.
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