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Progressive cladding system with corrosion protection function
Marek, Martin ; Taranza,, Luboš (referee) ; Drochytka, Rostislav (advisor)
Corrosion of reinforcement in reinforced concrete is a huge problem. Corrosion of reinforcement has a great effect on the service life of reinforced concrete structures. The subject of this work is to verify the inhibitors properties and their efficiency using physical and electrochemical methods. The aim of this work is the design of formwork panels with corrosion protection. The formwork panels are on different material basis. Corrosion protection is ensured by the use of migration corrosion inhibitors.
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Preparation and characterization of highly hydrophobic coatings on AZ 91 magnesium alloy
Šomanová, Pavlína ; Hasoňová, Michaela (referee) ; Doskočil, Leoš (advisor)
Magnesium and its alloys have many interesting properties and thanks to them it can be used in many applications (transport industry, medicine etc.). Disadvantage of these materials is their high corrosion rate. For this reason, there is an effort to achieve high corrosion resistance through different modifications of magnesium and its alloys. In recent years the superhydrophobization of the surface seem to be an attractive solution for this question. This type surface modification minimalize contact between the surface and water. In this diploma thesis the superhydrophobic surface was created on the magnesium alloy AZ91. The first step included pretreatment of AZ91 surface by etching in solution of SnCl2 or ZnCl2. Next step was superhydrophobization in the ethanolic solution of stearic acid. The surface morphology and elemental analysis of the superhydrophobic coating were explored by use of scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The adhesion properties of the coating on the AZ91 were analysed by means of scratching test. Contact and sliding angles were measured for superhydrophobic coatings. Electrochemical characterization of the coatings was determined using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS). Finally, the analysis of composition and the functional groups was made using Fourier-transform infrared spectroscopy (FTIR) and the phase composition analysis was performed using X-ray diffraction (XRD). The results show that the coatings prepared by etching did not lead to good corrosion properties, even though the value of contact angle was about 150 °. The reduction of corrosion resistance could be caused by not obtaining required surface morphology or insufficient binding of stearic acid in the form of stearate to the sample surface.
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Poly-para-xylylene films preparation and characterization of their properties
Menčík, Přemysl ; Salyk, Ota (referee) ; Přikryl, Radek (advisor)
Poly-p-xylylene is a basic polymer of parylene family. It was discovered in 50s of the 20th century. In practical applications, there are used several derivates. Most of them are discussed in this thesis. Poly-p-xylylene has many utility properties, like barrier, thermal and mechanical properties. It can be used for conservation and protection of electronic equipments, medical tools and devices or museum exhibits. The most important property of parylene is its low dielectric constant which enables parylene to have good insulating properties in form of very thin layer. The most common precursor used for parylene coatings by Chemical Vapor Deposition (CVD) is [2,2]paracyclophane. Special device invented for this process was described in this thesis, including every part and assembly. The main aim of this thesis was to test properties of thin parylene layers on metal samples. High degree of polymer crystallinity was confirmed by confocal laser microscopy and optical microscopy in the polarized light measurements. Problems in the conventional method of production of parylene layers were found during the measurement of thickness of layers. Purity of deposited films was determined using Infrared spectroscopy (IR). Parylene barrier properties were quantified by the measurement of Oxygen Transmission Rate through a layer deposited on the surface of PP foil. Because the research has been mainly focused on protection of museum exhibits, the corrosion resistance test is the most important. Metal samples with thin parylene film were compared to samples with conventional restoration coating. The samples with parylene protection were slowly corroded by point corrosion. In contrast to them, the samples conserved by conventional restoration method were almost destroyed by corrosion.
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Corrosion protection by means of plasma spraying coatings
Bartoněk, Daniel ; Řehořek, Lukáš (referee) ; Jan, Vít (advisor)
This thesis is focused on making study of technologies used for applying metal coatings as corrosion protection and commonly used materials. By means of metalographic analysis compare microstructures of coatings thermal spraying by zinc based alloys. The thesis is describing basics of corrosion, means of corrosion protection and methods used for making zinc coatings for corrosion protection. Experimental part is comparing coatings made by thermal plasma spraying and thermal spraying with use of electric current.
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Digital controlled power source with GSM
Buday, Martin ; Streit, Jakub (referee) ; Bradáč, Zdeněk (advisor)
Content of this diploma thesis is project of the digital control design for a thyristor source with GSM communication. Designed for corrosion protection. The work contain design of the whole device from the initial proposals of the electro diagrams up to finished product. It describes the events that arise in corrosion, explains the principle of operating a thyristor as a power switch. It also describes the creation and structure of a simple menu using the STM32 microprocessor. It explains the principle of controlling a source. Next, it deals with controlled rectifiers using a thyristor.
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Electrophoresis coating
Holčapek, Jiří ; Kubíček, Jaroslav (referee) ; Žák, Ladislav (advisor)
This bachelor is based on a study of electrophoresis coating and corosion. The first part contains information about corrosion of metal and the importance of protecting metal parts. Then it deals with the technology of electrophoresis coating and technological process of creating electrophoresis coating. Finally, new trends in the field of electrophoresis coating are presented.
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Use of acoustic emission technology to assess corrosion of materials
Procházka, Adam ; Vašíková, Simona (referee) ; Binar, Tomáš (advisor)
The thesis deals with the description of acoustic emission as a non-destructive testing method and its use in the detection of material corrosion. The first part describes the theoretical principles dealing with the explanation of what acoustic emission is, how it is defined according to the standard, what are the types of acoustic emission and how it is tested. It then discusses corrosion, the types of corrosive environments where corrosion occurs and the types of corrosion tests. It also describes where acoustic emission has been used in practice and what experiments it has been used for in terms of material monitoring. The next part of the paper describes the experiment of acoustic emission measurement on grey cast iron samples, describes the fabrication of the samples, the use of corrosion protectors, and the placement of the samples in a condensation chamber for continuous testing. The last part is the evaluation of the results .
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Preparation and characterization of highly hydrophobic coatings on AZ 91 magnesium alloy
Šomanová, Pavlína ; Hasoňová, Michaela (referee) ; Doskočil, Leoš (advisor)
Magnesium and its alloys have many interesting properties and thanks to them it can be used in many applications (transport industry, medicine etc.). Disadvantage of these materials is their high corrosion rate. For this reason, there is an effort to achieve high corrosion resistance through different modifications of magnesium and its alloys. In recent years the superhydrophobization of the surface seem to be an attractive solution for this question. This type surface modification minimalize contact between the surface and water. In this diploma thesis the superhydrophobic surface was created on the magnesium alloy AZ91. The first step included pretreatment of AZ91 surface by etching in solution of SnCl2 or ZnCl2. Next step was superhydrophobization in the ethanolic solution of stearic acid. The surface morphology and elemental analysis of the superhydrophobic coating were explored by use of scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The adhesion properties of the coating on the AZ91 were analysed by means of scratching test. Contact and sliding angles were measured for superhydrophobic coatings. Electrochemical characterization of the coatings was determined using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS). Finally, the analysis of composition and the functional groups was made using Fourier-transform infrared spectroscopy (FTIR) and the phase composition analysis was performed using X-ray diffraction (XRD). The results show that the coatings prepared by etching did not lead to good corrosion properties, even though the value of contact angle was about 150 °. The reduction of corrosion resistance could be caused by not obtaining required surface morphology or insufficient binding of stearic acid in the form of stearate to the sample surface.
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Electrophoresis coating
Holčapek, Jiří ; Kubíček, Jaroslav (referee) ; Žák, Ladislav (advisor)
This bachelor is based on a study of electrophoresis coating and corosion. The first part contains information about corrosion of metal and the importance of protecting metal parts. Then it deals with the technology of electrophoresis coating and technological process of creating electrophoresis coating. Finally, new trends in the field of electrophoresis coating are presented.
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