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Corrosion resistance of surface treatments by polysiloxane paint systems.
Kulhanová, Veronika ; Molliková, Eva (referee) ; Tulka, Jaromír (advisor)
Influence of atmospheric and chemical environments on metal products leads usually to the corrosion damage. This master´s thesis deals with way to protect metals from corrosion, especially by polysiloxane coatings in combination with coatings containing zinc. Corrosion resistance of created coatings systems is tested by laboratory accelerated tests in corrosion chamber, where the natural atmospheric conditions are simulated. Chemical resistance in selected environments is verified by drop test. Quality characteristics coatings – thickness, adhesion to the underlying material, hardness and stability of the coating colour and gloss are evaluated too.
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Evaluation of electrochemical characteristics of AZ31 wrought magnesium alloy
Hána, Tomáš ; Tkacz, Jakub (referee) ; Drábiková, Juliána (advisor)
This thesis deals with the issue of electrochemical characterization of AZ31 wrought magnesium alloy, which was exposed to corrosive environment of 0.1 moldm3 solution of sodium chloride. Electrochemical impedance spectroscopy and potentiodynamic tests were used for evaluation of electrochemical characteristics such as corrosion rate, corrosion current density, corrosion potential and polarization resistance. There is a summary of ways of a production of magnesium alloys, influence of alloying element on properties of material and types of corrosion, which leads to degradation of material in the theoretical part. In the experimental part there is characterization of used methods, summary of results and a discussion of obtained data and its comparison.
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Galvanic zinc coating
Půček, František ; Dvořák, Milan (referee) ; Žák, Ladislav (advisor)
This thesis is based on elaboration and full description of galvanic zinc coating, operations and technologies used in them. The thesis is aimed on analysis of corrosion. How is it formed and how is it spreading. The thesis is also aimed on physical-chemical process which takes place on the surface of coated part during technologies used in galvanic zinc coating. The thesis also emphasize on choosing the right method so we can achieve the best results and good economic conditions. In conclusion the thesis analyzes defections in galvanic zinc layer.
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Passivation of magnesium alloys
Krejčířová, Dana ; Sponar, Jan (referee) ; Zmrzlý, Martin (advisor)
Diploma thesis deals with the technology of surface modifications of magnesium alloys. Basic knowledge from the field of the corrosion of metal materials. The division corrosion according to way of attack and corrosion environment, etc. There is an enumeration of ways of the corrosion defence. Questions of surface modifications with an emphasis on passivation by conversion coating and its analysis. Characteristics of magnesium and its alloys. Magnesium alloys with lithium, possibilities of its passivation and the verification of corrosion resistance. Enumeration of the used devices, chemicals and materials. characteristics of the used alloys. creation of the corrosion resistance standard. Research in passivation on the alloy containing 12 percent of lithium. The verification of the corrosion test usability based on the suggestion of the background research results. The test results for passivated as well as untreated samples and the reference material (steel). Aplication of chromate-free passivation and corrosion test on the alloy containing 12 percent of lithium.
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Zinc coatings
Zdařil, Lubor ; Trčka, Josef (referee) ; Zmrzlý, Martin (advisor)
The aim of this work is a description of corrosion as a major phenomenon in the degradation of the material and the description basic types of corrosion. Then the material protection possibilities are described using a suitable choice of surface treatment. From the wide field of coating systems, electrodeposited zinc based alloys coatings were emphasized. theirs subsequent increase of corrosion resistance by applying powder coatings. Alloy coatings that are in the focus of recent research were discussed.
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Surface treatment of spherical pin
Plášil, Petr ; Kubíček, Jaroslav (referee) ; Žák, Ladislav (advisor)
Diploma thesis is worked-up as a part of master’s studies of engineering technology M2I – K, analyzing the possible methods of surface treatment of spherical pin, that increase its corrosion resistance. Spherical pin is mounted into several types of chassis components such as joints, control arms, etc. The current situation is inconvenient for manufacturers, insufficient corrosion protection increases the number of complaints and this may be reflected in the number of future orders. Via of suitable surface treatment is to achieve a higher corrosion resistance while maintaining the functional properties of pins used.
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Galvanic zinc coating
Hamal, Jan ; Kubíček, Jaroslav (referee) ; Žák, Ladislav (advisor)
This thesis is based on analysing and description of galvanic zinc coating, operations and technologies used in them. The first part contains an analysis of corrosion and is aimed on physical-chemical process which takes place on the surface of coated part. The thesis also emphasize the choice of technology for zing coating and in conclusion analyzes defections in galvanic zinc layer.
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Replacement of nickel alloy overlay by manganese alloy overlay
Hlobil, Albert ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The thesis is focused on the issue of tuning the welding process of the 18.8. Mn alloy using the method 152. The welded component is the cylindrical throat of a Venturi tube made of ASME SA-106 Grade C carbon steel. A series of welds were performed, which were qualitatively evaluated and compared. Metallographic sections were made, and the dilution, excess, and width of the heat-affected zone were determined. Evaluation of microstructure and microhardness were also performed. Based on the tests performed, suitable welding process parameters were used. For comparison, a test for chemical and salt mist corrosion was undertaken, where the corrosion resistance of the 18.8. Mn alloy weld was compared to Inconel 625 alloy.
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