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Cold sintering of dielectric materials
Kocman, Lukáš ; Prajzler, Vladimír (referee) ; Salamon, David (advisor)
CSP (Cold Sintering Process) is an innovative production route due to the dramatic reduction in sintering temperature and processing time, which leads to a reduction in energy and production costs. During this low temperature process, the ceramic powder is compacted using a liquid phase under intense uniaxial external pressure and limited heating conditions (typically below 400 °C). Barium titanate BaTiO3 has gained worldwide interest from the scientific community due to its excellent dielectric, ferroelectric and piezoelectric properties. In particular, it is a suitable candidate for dielectric ceramic materials for energy storage. Barium titanate can be prepared by various methods, where the synthesis depends on the desired properties for the final application. The method used has a significant effect on the structure and properties of the materials. In the experimental part of the work, BaTiO3 samples were prepared by the cold sintering method and the possibility of doping ceramic materials during the cold sintering process was investigated. Furthermore, various factors and influences such as heating rate, temperature, dwell time, maximal pressure or sintering flux on the compaction and dielectric properties of the material were discussed.
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Improving Efficiency Concept of Machining Technology of Chimney Liner
Kubů, Marek ; Kyncl, Jiří (referee) ; Sedlák, Josef (advisor)
Diploma thesis contains introduction of a company P-D Refractories CZ a. s., where the manufacture of ceramic chimney liners is. Followed by a description and analysis of the product in the entire production cycle, material and product spectrum. Based on the results of current production is created proposal to streamline the machining technology with a view to increase productivity and reduce defective products, which means determine the material of a tool and the method of machining. The work is finished by technical-economic assessment, where the summary and recommendation of the proposed solution are.
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Semiconducting ceramics for thermoelectric application
Jebavá, Alžběta ; Koplík, Jan (referee) ; Bartoníčková, Eva (advisor)
This diploma thesis focuses on the syhnthesis of multicomponent ceramic system based on Ca-(Mn,Co)-O. The thesis is devided in theoretical and experimental part. The theoretical part is describing ceramic materials for thermoelectric application, preparation and synthesis of these materials and their processing. The experimental part is dealing with synthesis of ceramic powder which is processed to the porous ceramics. The properties of prepared porous ceramics are observed.
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Calculation of the probability of the endoprosthesis ceramic head with shape deviation
Kučerková, Miroslava ; Fuis, Vladimír (referee) ; Kovář, Jaroslav (advisor)
The main content of the diploma thesis is to determine the probability of failure of the hip joint endoprosthesis ceramic head. The assumption is the three-axis state of stress. To calculate the probability of failure three principal stresses, which are determined numerically using finite element method, are needed. Ceramic materials, hip joint endoprosthesis and Weibull weakest link theory, which describes the calculation of the probability of failure of ceramic components, are described in the first part of the thesis, after that, the second part with calculations follows. The first model, for which the stress and probability of failure were calculated, is a cylindrical body. The stress distribution in it was determined numerically as well as analytically. Its primary goal is to verify the developed algorithm of calculating the probability of failure. This algorithm is also used in calculations of probability of failure of ceramic femoral head. The suitability of using averaged principal stress values was also verified here. In the next part of the thesis, a model of an ideal ceramic head was created and its probability of failure was calculated. The impact of friction, penetration and the size of elements used for discretization of the model on the value of probability of failure were all analysed. The evaluated findings were subsequently used in the calculations of the model of ceramic head with an deviation from the ideal ovality. The impact of this change on the resulting probability of failure in comparison with the ideal state was evaluated in the conclusion.
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A study on the grinding of ceramic materials
Kresa, Jakub ; Sliwková, Petra (referee) ; Píška, Miroslav (advisor)
This thesis is focused on ceramics materials in terms of their partition, properties, structure, manufacture and methods of their possible machining. The first part of this thesis is devoted to the distribution of ceramics materials, their structure, properties, and methods of production. Currently, ceramics materials are increasingly used in structural (engineering) applications therefore we deal with methods of effective machining of ceramic materials, to achieve part of the required shape, dimensions and surface quality. The evaluation of ceramic grinding test from the point of view of cutting forces and surface quality of the machined faces are presented in the last part of the thesis. The tested materials have been provided by company SEEIF Ceramics a.s.
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On the milling of refractory ceramic materials
Reiter, Milan ; Polzer, Aleš (referee) ; Píška, Miroslav (advisor)
Diploma thesis is focused on machining of refractory ceramics materials. The theoretical part describes the division of ceramics materials, their structure, manufacture and properties. This part also contains the division of refractory ceramics. In the second chapter, of ceramics materials are described machining. The latest chapter is focused on analyzing the machinability of ceramics materials R - SLI - K. During the experiment, cutting conditions were changed and cutting forces were checked. Then surface roughness was measured and tool wear was observed.
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Calculation of the probability of the endoprosthesis ceramic head with shape deviation
Kučerková, Miroslava ; Fuis, Vladimír (referee) ; Kovář, Jaroslav (advisor)
The main content of the diploma thesis is to determine the probability of failure of the hip joint endoprosthesis ceramic head. The assumption is the three-axis state of stress. To calculate the probability of failure three principal stresses, which are determined numerically using finite element method, are needed. Ceramic materials, hip joint endoprosthesis and Weibull weakest link theory, which describes the calculation of the probability of failure of ceramic components, are described in the first part of the thesis, after that, the second part with calculations follows. The first model, for which the stress and probability of failure were calculated, is a cylindrical body. The stress distribution in it was determined numerically as well as analytically. Its primary goal is to verify the developed algorithm of calculating the probability of failure. This algorithm is also used in calculations of probability of failure of ceramic femoral head. The suitability of using averaged principal stress values was also verified here. In the next part of the thesis, a model of an ideal ceramic head was created and its probability of failure was calculated. The impact of friction, penetration and the size of elements used for discretization of the model on the value of probability of failure were all analysed. The evaluated findings were subsequently used in the calculations of the model of ceramic head with an deviation from the ideal ovality. The impact of this change on the resulting probability of failure in comparison with the ideal state was evaluated in the conclusion.
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