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Surface Modification of Zinc Alloys
Kinc, Marek ; Foral, Karel (referee) ; Molliková, Eva (advisor)
The object of this bachelor’s thesis is to create a research in field of zinc alloys. In the first part, there are outlined production of pure zinc with a different methods and briefly described the treatment of waste. The next are described the zinc alloys and their properties and outline the ways of die casting. The end of this thesis is focused on methods of finishing the surfaces.
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Surface pre-treatment of structural aluminum alloys for bonded joints
Pikner, Jan ; Doskočil, Leoš (referee) ; Wasserbauer, Jaromír (advisor)
This thesis deals with pre-treatment of surface of aluminium alloys. The theoretical part focuses on the properties of aluminium and its alloys, on methods of surface treatment and the possibilities of quality assessment of pre-treated surface. The experimental part deals with finding of a proper method of pre-treatment. The quality of surface pre-treatment is assessed by observation by SEM with EDS and by single lap shear tests of adhesive joints. According to evaluated results, the optimalised methods are qualitatively and financially compared with the commercial method.
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Possible design and performance mistakes of welds for resulting chemical threatment by pickling
Hendrych, Marek ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The diploma thesis deals with the issue of surface treatment by pickling. In the research part the pickling technology is described in detail. The next chapters are focused on the TIG welding method and the weldability of austenitic stainless steels. In the experimental part an experiment is carried out focusing on the comparison of weight loss and surface quality depending on the pickling time. Part of the conclusion is the implementation of pWPS documentation for the specified component and a brief manual for customers of pickling plant.
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Passivation of the active layer in perovskite solar cells with inverted architecture
Babincová, Kristina ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
The topic of this work is the passivation of the active layer of perovskite solar cells with an inverted structure. The work is divided into theoretical and experimental part. The theoretical part describes in particular the passivation and modification of the perovskite layer as well as the characteristic properties of perovskite, including structure and stability. The experimental part deals with the preparation of photovoltaic cells with an inverted structure. For the characterization of photovoltaic cells, reference samples were prepared and their active layer was modified by plasma. The most used deposition technique for the preparation of layers was the spin coating method. From the performed experiments it can be concluded that the preparation of samples and their subsequent modification under laboratory conditions does not lead to the improvement of the final parameters of photovoltaic conversion. By transferring the sample preparation and passivation of the active layer to an inert atmosphere, it was possible to produce cells with higher efficiencies (compared to the reference sample), around 10 %. Another advantage of this plasma treatment of the active layer is that it also improves the stability of the prepared structures, which even after a few days in air show almost 80 % of the original efficiency.
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Passivation of Aluminum and Aluminum Alloys in passivation baths without Cr6+ Compounds
Macháč, Pavel ; Tulka,, Jaromír (referee) ; Molliková, Eva (advisor)
This diploma thesis deals with evaluation of efficiency of protection conversion coatings created by passivation metals and alloys in passivation baths without chromium compounds. The theoretical part is initially concerned with question of electrochemical corrosion of metals, consequently there are mentioned different methods of corrosion protection. The main section of theoretical part of this thesis deals with chromate conversion coatings, description of their protective efficiency (including their unique self-healing effect) and then with account of new chromate-free conversion coatings occurring as chromate alternatives, whose usage is constrained because of their content of hexavalent chromium, which is highly toxic, oxidizing and also carcinogenic and thereby very dangerous for human body and the environment. Experimental part of this thesis is concerned with evaluation of efficiency of particular conversion coating which is quite commonly use in some applications as chromate alternative. It is chromate-free conversion coating which is created by passivation of metals or alloys in passivation bath Pragokor BP, which contains zirconium fluorocomplexes and is without any chromium or other toxic or ecologically unhealthy compounds. The influence of sealing of the coating in preparation Pragokor Seal Al and also other surface treatments such as application of conservation wax WAXENG or cold application of zinc coating were tested too. Efficiency of mentioned surface treatments was then evaluated on aluminum and steel by laboratory accelerated and atmospheric corrosion testing.
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Stainless steels
Chára, Tomáš ; Kalina, Lukáš (referee) ; Zmrzlý, Martin (advisor)
This thesis deals with stainless steels. The theoretical part describes the mechanisms and types of corrosion. Then the thesis deals with the properties, distribution and manufacture of the stainless steels and a brief description of the XPS method used for the practical part. In the recherche section summarizes the ways of using the XPS method for determining the quality of the passive layer of stainless steels eaten in different environments. Practical task was to compare the quality of the passive layer of stainless steels resulting from natural and chemical passivation.
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Passivation of germanium surface using ALD
Kuba, Jakub ; Polčák, Josef (referee) ; Kolíbal, Miroslav (advisor)
The thesis deals with passivation of germanium surfaces by chemical etching and atomic layer deposition (ALD). Attention was paid to the rate of oxidation of germanium surfaces after selected passivation methods and the composition of the germanium suboxides. In the thesis selected methods for germanium oxide removal are reviewed and a brief description of the methods used for analysis (XPS) and thin film deposition (ALD) is given.
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