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Corrosion of Steel and Aluminium in Chosen Enviroments
Stavinoha, Jakub ; Tulka, Jaromír (referee) ; Molliková, Eva (advisor)
This Master’s thesis is related to corrosion degradation processes on metal surfaces exposed in different environments. The theoretical part is concern with basic principles in electrochemical and atmospheric corrosion. Practical part describes experimentation of corrosion process of aluminium (99,5) and low carbon steel (11321) in two different atmospheric environments. The conclusion of thesis includes evaluations of the results from practical part and comparison with the theoretical part.
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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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Biodegradable bone implants based on iron
Müller, Petr ; Kazda, Tomáš (referee) ; Sedlaříková, Marie (advisor)
The present work deals with the comparison of the properties of metallic biomaterials in terms of their suitability for use as a temporary metal implant. In the work is judged biocompatibility of materials, they are comparing the corrosion rates and the influence of additives in the iron alloy to change biocompatibility and corrosion rate. In a part of this work is suggesting a method of preparing biodegradable metallic samples with different alloying elements and determine the methods, processes and measuring the corrosion rates. Part of this work is the chapter dealing with the function and effect of iron in the human body and any complications that may occur when a surplus caused by the release of part of the implant during its degradation or corrosion products. The outcome of this work is sort of created an iron-based samples in terms of their electrochemical corrosion potential, corrosion rate of samples exposed in various corrosive solutions, spectroscopic elemental analysis and outputs from the microscopic observation of the structures.
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Measurement of the corrosion of the public lighting
Jalový, Michal ; TSB,, Josef Šaroun, provozně-technický ředitel (referee) ; Krutílek, David (advisor)
This thesis describes corrosion degradation processes taking place on the surface of metal materials in different environments. The theoretical part deals with basic environments we encounter in practice. This part specifies protection of materials against the aggressive environments and provides principles of corrosion measurement. It analyses the issue of corrosion measurement and its impact on mechanical strength of structures. It deals with the application of Electrochemical Impedance Spectroscopy (EIS) method for measurement of public lighting corrosion and identification of potential breakdown.
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Assessment of probable causes of corrosion damage of a mould made of cast iron
Sobola, Petr ; Pantělejev, Libor (referee) ; Man, Ondřej (advisor)
Bachelor’s thesis deals with solution of problems on glass moulds, which were exposed to the corrosion medium for up to two days causing their damage. The thesis contains theoretical analysis of the problem, layout for the corrosion experiment and its execution. Based on the experiment a conclusion was pronounced that the extent of damage which was observed was not able to be created by corrosion of initial surface without any previous defect.
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Assessment of probable causes of corrosion damage of a glass-shaping mould
Jíša, Jakub ; Pantělejev, Libor (referee) ; Man, Ondřej (advisor)
The aim of this thesis was to characterize briefly the issue of electrochemical corrosion in the aquatic environment with a focus on cast-iron corrosion and then decide whether the observed damage to the glass-forming mold could arise in the course of two days. A simple corrosion experiment was made in which samples of cast-iron were exposed to the shower of water for 48 hours. Corrosion damage under simulated conditions did not reach the level of damage of the mold.
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Corrosion of Metals in Chlorides According to Global Harmonized System
Kundrát, Vojtěch ; Tulka,, Jaromír (referee) ; Tulka,, Jaromír (referee) ; Molliková, Eva (advisor)
Transportation of chemicals and mixtures often leads to corrosive damage to their protective packaging, which could cause leakage of transported chemicals to the surroundings. This thesis deals with the corrosive effects of a solution which contains distilled water with 5 wt. % of NaCl solution and distilled water containing 2.5 wt. % of NaCl and 2.5 wt. % of urea. Samples of aluminium with purity of 99.5 % and non-alloy steel EN 10131 were exposed to these corrosive environments. Based on the performed corrosion tests were evaluated weight losses, the speed of corrosion, metallographic evaluation and comparison of results with the criteria according to the OECD methodology, which is indicated by GHS.
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