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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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Nanopatterned alumina-based materials for electrochemical sensors and biosensors
Kynclová, Hana ; Hynek, David (referee) ; Trnková, Libuše (referee) ; Prášek, Jan (advisor)
The doctoral thesis is focused on basic research and development of nanostructured surfaces prepared using anodic alumina material. Various types of gold nanostructured surfaces and nanoporous aluminum membranes for electrochemical sensors and biosensors were prepared using the anodic oxidation method. Nanostructured surfaces were prepared by electrochemical anodization of aluminum material to form hexagonally arranged nanopores. Gold was then deposited into the nanoporous masks by electrochemical reduction from potassium dicyanoaurate solution using a pulse deposition method. The prepared nanostructured gold surfaces were electrochemically characterized by electrochemical impedance spectroscopy and voltammetry. Temperature stability and the effect of annealing on their electrochemical behavior at atmospheric pressure as well as in the vacuum were investigated. Then, gold nanostructures of various dimensions were prepared and the influence of their shape and dimensions on the electrochemical behavior was studied. Nanostructured surfaces were also modified with 11–mercaptoundecanoic acid, and the effect of this modification on the electrochemical results was studied. In the last part of the work, nanoporous aluminum membranes were prepared, and their permeability was studied.
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New nanodevices for electronics - fabrication and characterization
Márik, Marian ; Husák,, Miroslav (referee) ; Mikulík,, Petr (referee) ; Hubálek, Jaromír (advisor)
Táto práca sa zaoberá technikou výroby samousporiadaných nanoštruktúr pre elektrické aplikácie. Prototypy boli pripravené anodickou oxidáciou v dvoch dĺžkach a tromi rôznymi tepelnými úpravami. Štrukturálna charakterizácia bola spravená pomocou techniky SEM, TEM a EDX a vyhodnotenie nielen z štrukturálneho, ale aj z materiálového hľadiska. Jedinečná koreňová štruktúra samousporiadaných nanotyčiniek bola vyhodnotená a porovnaná po troch rôznych tepelných úpravách: po anodizácii, po vákuovom žíhaní, a po žíhaní vo vzduchu. Všetky prototypy obsahujú nanotyčinky s amorfnou štruktúrou, ale našli sa však aj nanokryštály pod koreňovými štruktúrami. Elektrická charakterizácia prototypov ukázala: odporové spínacie správanie (RS), diódové charakteristiky a charakteristiku podobnú pre diódy s kapacitorom. Aktívny povrch pre spínací mechanizmus je v hornej časti nanoštruktúr na rozhraní nanotyčiniek a zlatej elektródy. Výška Schottkyho bariéry na rozhraní Ti / TiO2 bola vypočítaná dvoma spôsobmi a pre všetky tri zariadenia bola nižšia ako 1,11 eV.
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The influence of modified TiO2 nanotubes on biointerfacial interaction
Bílek, Ondřej ; Kočí,, Kamila (referee) ; Hlaváček,, Antonín (referee) ; Fohlerová, Zdenka (advisor)
Nanotrubičky oxidu titaničitého v průběhu posledních let nabyly na významu v poli biomedicíny. Jakožto biokompatibilní nanostrukturovaný povrch nachází potenciál pro své uplatnění především v oblasti implantačních aplikací. Teoretická část této práce je tak věnována různým přístupům pro syntézu TiO2 nanotrubiček, jejich modifikacím a aplikacím v biomedicíně. Experimentální část pak pojednává o nanotrubičkách oxidu titaničitého, které jsou připraveny z titanu metodou jednokrokové anodické oxidace v organickém elektrolytu. Jako výchozí materiály jsou používány křemíkové disky s naprášenou vrstvou titanu a titanové folie. Zprvu amorfní nanotrubičky jsou žíháním převedeny na svou krystalickou podobu, a následně modifikovány selenovými a stříbrnými nanočásticemi. Připravené struktury jsou zkoumány z hlediska povrchových vlastností a biologických interakcí s vybranými tkáňovými kulturami (MG-63, NIH-3T3) a bakteriemi (E. coli, P. aeruginosa, S. aureus). V závěru experimentální práce jsou stručně porovnány výsledky selenových a stříbrných nanočástic. Hlavním cílem této práce je rozšířit znalosti týkající se bio-rozhraní tvořeným adherentními buněčnými liniemi, bakteriálními buňkami a nanostrukturovaným povrchem tvořeným TiO2 nanotrubičkami dekorovanými selenovými a stříbrnými nanočásticemi.
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The analysis of couses of the damage of stroller welded construction
Štarhová, Martina ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
This bachelor thesis deals with analysis of causes of damage of aluminum welded structures of baby carriages. The theoretical part contains a summary of information concerning the most frequently used aluminum alloys and their heat treatment. Furthemore, it deals with possibilities of welding and testing of welded joints, corrosion resistance of aluminum alloys. Basic information on the most frequently used surface treatment, anodic oxidation, is also mentioned. The experimental part of the work deals with a complex material analysis of three frames of baby carriages. This analysis is focused on mapping the occurrence of the most common defects and determining their contribution to damage or destruction of the baby carriage frame.
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Influence of Anodization Parameters on Morphology of Titania Nanotubes
Přikrylová, Kateřina
Highly ordered titania nanotubes (TNTs) were fabricated via electrochemical anodization of titanium thin film in fluoride and water containing organic electrolyte. Titanium film was sputter-deposited on silicon wafer with thermal silicon dioxide layer. The effects of applied anodization potential, electrolyte composition, anodization time on the formation of TNTs were discussed. The influence of anodization parameters on morphology of TNTs was observed by scanning electron microscopy (SEM). The anodization time mainly influenced TNTs length, while applied potential and electrolyte composition strongly affected the morphology of TNTs during the anodization process where the removing of initial barrier layer plays a significant role.
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Modeling of porous metal oxide layer growth in the anodization process
Habera, Michal ; Hron, Jaroslav (advisor) ; Pavelka, Michal (referee)
Under suitable conditions anodic metal oxidation leads to growth of complex porous structures. The initiation and growth of these structures is an interesting and challenging task for electrochemical modelling. One must identify chemical reactions in a multi-phase framework, derive a proper partial differential equations and solve them in time dependent domains. In this work, electrochemical model for the oxide growth in nano scales is presented. Physically motivated equations are formulated with precise mathematical meaning and existence of solutions is studied. Electrostatic potential fulfilling high-field conduction law and interfacial jump conditions is sought for. Numerical discretization is performed with the use of finite element method and free boundaries are tracked with characteristic level-set functions. Basic mechanism governing the growth of porous structures is given and numerical experiments are explained on it's basis. This thesis presents novel contributions to the electrochemical and mathematical picture of nanopores growth.
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Fabrication and characterisation of silver decorated TiO2 nanotubes for biomedical applications
Bílek, Ondřej ; Horynová, Miroslava (referee) ; Fohlerová, Zdenka (advisor)
This diploma thesis summarizes knowledge from the fields of synthesis, characterization and application of titanium dioxide nanotubes and its combination with silver nanoparticles for biomedical purposes. Basic protocols of working with cell cultures and bacteria are also included. Experimental part of this diploma thesis focuses mainly on the synthesis of tubular structures made of titanium dioxide via anodic oxidation of 500nm titanium layer and their subsequent decoration with silver by electrodeposition. Last section of the experimental part is devoted to testing of antibacterial properties of the new material and examining the effect of different silver concentrations on the adhesion of MG-63 cells. All results are compared to reference samples consisting of titanium dioxide nanotubes without silver.
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Nanostructured TiO2 as the surface for the investigation of cell behaviour
Poláková, Kateřina ; Urbánková, Kateřina (referee) ; Fohlerová,, Zdenka (advisor)
This thesis deals with the study of cells on nanostructured surfaces of titanium dioxide, which are produced by the electrochemical method called anodic oxidation. The theoretical part is formed by an overview of manufacturing nanostructured surfaces using anodic oxidation method. It mentions the influence of external factors on the geometric parameters of the structure and description of methods of characterization structures. Furthermore there is processed outline of use for biomedical application and the description of interaction of the cell with surface. The practical part includes description of the production of nanoporous and nano-tubular structures made on thin films of titanium by direct method of anodic oxidation on which was studied the influence of external factors. Described a procedure and production of nanorods structures and nanodots generated using alumina template (AAO) which is subsequently carried out the study of the behavior of cells, which includes tests of adhesion, examination of morphology of cells, assays of proliferation and differentiation. Structures are under investigation of the interaction of cells with the nanostructured layer compared with the smooth surface of the titanium dioxide.
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Defects and their causes in dyeing of anodized surfaces
Šulc, František ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
This thesis deals with the anodic oxidation of aluminum and its alloys. The work consists of two parts. The first one is focused on more detail description of anodic oxidation process itself and theoretical description of the technological process anodic oxidation. The second part is more practically oriented. It compares two different lines for anodizing, and examines factors that affect the final appearance of the surface layer during anodizing welded joints.
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