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Study of the microstructure of deposited Ni-P coatings with different phosphorus contents
Najser, Tomáš ; Kosár, Petr (referee) ; Wasserbauer, Jaromír (advisor)
The aim of this bachelor thesis was the preparation and characterization of Ni-P coatings with different phosphorus contents on the substrate of AZ91 magnesium alloy. The theoretical part deals with magnesium alloys and specifies the utilized substrate AZ91. It also focuses on Ni-P coatings, their microstructure and their properties. However, there are also described factors affecting the rate of deposition and the resulting behavior of these coatings. Last but not least, the theoretical part summarizes the basic principles of laboratory methods used in the experimental part for observation and characterization of samples. Conclusion of the theoretical part consists of several background researches where the authors deal with similar problems and factors influencing the resulting behavior of Ni-P coatings. The experimental part is focused on the deposition of each Ni-P coatings on the AZ91 alloy and their characterization. The study of deposited Ni-P layers was focused on the determination of their microstructural texture by XRD method, mechanical properties and elemental composition depending on phosphorus content.
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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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Optimal X-ray detection for thin samples in low-energy STEM
Rozbořil, Jakub ; Oral, Martin ; Radlička, Tomáš
In many applications it is desirable to perform energy-dispersive X-ray spectroscopy (EDS) on very thin samples at low primary beam energies in a STEM. Thin samples, or lamellae, with the thickness of about 10 nm, are mostly prepared in focused ion beam instruments (FIBs), and they are used to evaluate experiments in the development of thin films and coatings, in the semiconductor industry, and in other applications. EDS then provides a map of different chemical elements or compounds in the sample, obtained by scanning the electron beam in a raster. Often the qualitative composition is known as a limited set of materials and only their distribution on the sample is to be determined. For large batches of samples fast measurements are desired to maximize utilization of expensive equipment. In this study we found a method to minimize the time needed to reliably acquire an elemental map by determining the optimal detector placement and the minimal necessary primary electron dose per pixel.
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Heat and mechanical resistance of zinc coating
Horák, Karel ; Dzimko, Marián (referee) ; Černý, Michal (advisor)
The work is aimed at studying the thermal degradation of the protective zinc coating. Its large part deals with the structure of the various stages of transition and their arrangement, the main emphasis is on analysis of brittle intermetallic phases, which arise due to increased temperature. Conclusion of the work is trying to clear itself causes degradation of this protective layer.
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Comfort and Safety Systems - Diagnostic Methods
Slíž, Martin ; Lapčík, Josef (referee) ; Hájek, Vítězslav (advisor)
This work deals with the division and description of the safety featutes of vehicles. Gradual entry into the safety of the crew of the car, from simple to very complex safety systems. The first part of this work deals with the basic division of safety features to active and passive systems. Here summarizes the most frequently used systems, their advantages and disadvantages. In the second part is described in detail system ABS (Anti-lock system), principle of operation, construction and other features of the system. The third part deals with the diagnosis of failures of security systems. It also included the creation of disorders, their symptoms and solutions. The last part of the two concrete examples of the use of diagnostic measurement system for ABS.
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Properties comparison of two products used for skating rink based on ehtylene-propylene-dien rubber
Kostková, Jana ; Kučera, František (referee) ; Bálková, Radka (advisor)
This master thesis deals with characterization of two black and white products based on ethylene-propylene-diene rubber (EPDM) used for skating rink. Products marked with A and are different in their diameter of circular tubes trough which cooling medium passes and also in the distance of these tubes. Both of materials were characterized in order to determine whether it is the EPDM and how are they different. The characterization methods were used: differential scanning calorimetry, thermogravimetric analysis, attenuated total reflectance Fourier transform infrared spectroscopy, tensile test, swelling test, thermooxidative test. The composition of both materials, including fillers and others additives is almost the same but difference is in structure of EPDM and probably also in interaction with fillers, what exhibits different mechanical properties, thermooxidative stability and thermal capacity. These differences which have been found are essential for long-term use properties of both materials.
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Bulk properties of fine particulate solids as the function of the selected material parameters.
Slanina, Ondřej ; Roman,, Fekete (referee) ; Svěrák, Tomáš (advisor)
The theoretical part of the thesis focuses on the description of particulate materials and their mechanical behaviors with a focus on flow properties. Great emphasis is placed on measuring the shear properties using a Jenike shear machine, on the correct procedure for standardized measurement and evaluation using Mohr's circles. The theoretical part focuses on the characterization of particulate matter using a variety of methods available, such as visual, separation, sedimentation, surface methods and methods of scanning field and flow. The practical part is focused on the determination of flow characteristics and surface finishing of finely ground limestone Omyacarb VA with various grain sizes. The surface was modified using stearic acid and calcium stearate. Attention was paid to the influence of the concentration of surface-regulating substances on the flowability of the material. The flowability of commercially supplied material was compared with lab modified materials and the determination of the theoretical content of stearic acid or calcium stearate was accomplished. Shear properties were measured using the Jenike shear machine. The material was further tested by laser diffraction and SEM with EDS particle surface analysis and elemental surface mapping.
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European Diplomatic Service
Arnoldová, Barbora ; Gullová, Soňa (advisor) ; Klosová, Anna (referee)
The topic of this bachelor thesis is the European Diplomatic Service, officially called as the European External Action Service (EEAS). The EEAS is a functionally autonomous body of the European Union. It is placed under the authority of the High Representative of the Union for Foreign Affairs and Security Policy and shall support him in fulfilling his mandate. The goal of this bachelor thesis is to define the main principles of organisation and operating of the EEAS. The thesis is divided into four chapters - Diplomacy (formation, characteristics,goals, basic definition of terms), external activities of the EU members, external action of the EU, EEAS.
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