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Two-step sintering of advanced ceramic materials with various crystal structures
Žalud, Pavel ; Trunec, Martin (referee) ; Maca, Karel (advisor)
The influence of Two-Step Sintering (TSS) process on the final microstructure of oxide ceramics materials with two different crystal structures was studied. Tetragonal zirconia (stabilized with 3mol%Y2O3, particle size 90nm and 140nm ) and cubic zirconia (8mol%Y2O3, 70nm) powders were cold isostatically pressed and pressure less sintered with different heating schedules. The microstructures achieved with TSS method were compared with microstructures achieved with conventional Single-Step Sintering schedule (SSS). The results showed that the efficiency of the TSS of these oxide ceramics was more dependent on their crystal structure than on their particle size and green body microstructure. The method of TSS brought only negligible improvement of the microstructure of tetragonal zirconia ceramics. On the other hand, TSS was successful in the sintering of cubic zirconia ceramics; it led to a decrease in grain size by a factor of 2.
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Modern processing methods of porous bioceramics
Šťastný, Přemysl ; Částková, Klára (referee) ; Trunec, Martin (advisor)
Bachelor thesis is written with focusing to bioscaffolds. Thesis is devided into three parts. First part is focused to colloid suspensions, their preparation and consolidation. Second part is focused to preparation methods of porous ceramics. The third part describes scaffolds and their use in medicine. Practical part is focused to gels preparation.
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Preparation of large and complex-shaped ceramics parts
Prehradná, Jana ; Pouchlý, Václav (referee) ; Trunec, Martin (advisor)
This bachelor’s thesis deals with research of ceramic materials in field of material engineering. The first part deals with biomaterials, especially bioceramics, its types, properties and its usage. The second part of this thesis deals with transparent ceramics and the third part includes the procedure and method of gel casting. The experimental part is dedicated to production of large and complex shaped components - knee joint, spherical cover and discs with transparent properties. The method of gelcasting was used for samples preparation of this type. The task was not only to produce these samples, but also to find suitable surrounding conditions for the proper course of the entire production process.
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Compaction of ceramic nanoparticle suspensions by centrifugal forces
Mišák, Jiří ; Maca, Karel (referee) ; Trunec, Martin (advisor)
In bachelor’s thesis, there was researched compacting of ceramic suspensions prepared from aluminium oxide with particle size of 100 nm by centrifugal forces. The homogeneity of centrifuged bodies was described in dependence of the speed of centrifugation. It was shown, that homogenous plate samples with regular particle packing could be prepared from centrifuged bodies. The structure and sintering behaviour of such bodies were superior to samples prepared by cold isostatic pressing. Similar properties could be reached in samples prepared from suspension with high loading (47,5 vol.%) as well as with lower loading (20 vol.%). The advantage of regular and dense particle packing by centrifugal compaction was demonstrated by manufacturing of transparent ceramic samples.
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Thermoplastic extrusion of ceramic materials with ionic and mixed conductivity
Kaštyl, Jaroslav ; Matoušek, Aleš (referee) ; Trunec, Martin (advisor)
In the bachelor thesis, an overview of the existing literature focused on thermoplastic extrusion method was worked out and based on the findings; the conditions for extrusion of mixtures with zirconia were optimized in order to produce rods. Great attention was paid to dimensional and shape precision of ceramic parts. Two methods were applied when preparing the ceramic mixtures – mixing and dissolving. These methods have been compared on the basis of the results achieved in rheological measurements of flow properties, microstructure and dimensional accuracy of the sintered rods. Having verified the efficiency of mixture dissolving, this method was used to prepare mixtures with different contents of cellulose and binder.
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Ceramic materials with foam structure
Šenk, Vít ; Trunec, Martin (referee) ; Cihlář, Jaroslav (advisor)
Bachelor’s thesis is concerned to preparation ceramic materials with a foam structure suitable for supporting, catalytic and biological applications. A part of work is focused on preparation ceramic substrates such as alumina, zirconia and foam materials for catalytic applications based on perovskite materials. Process of preparation ceramic foam structures consists of stable ceramic slurry prepared by different methods, drying, thermal extraction and evaluating sintered structure.
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Gelcasting of Advanced Ceramics
Veselý, Jan ; Maca, Karel (referee) ; Trunec, Martin (advisor)
In Bachelor thesis, a literary overview of gelcasting method was worked out and pursuant to this overview, composition of alumina suspension was optimised for fabrication of bulky and complex-shape ceramic part. Four variants of ceramic powder filling in suspensions were prepared. Based on the experiments, a suspension with powder loading of 47,5 vol. % was chosen. The ratio between linear and crosslinking monomers was investigated for this suspension. A suspension with monomer ratio of 4 : 1 (linear : crosslinking) was chosen for preparation of bulky and complex-shape ceramic part. Gelcasting was verified by fabrication of ceramic medal and a knee-joint.
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Processing of Electroceramics from Nanopowders
Kachlík, Martin ; Trunec, Martin (referee) ; Maca, Karel (advisor)
Literature review of processing of bulk EuTiO3 ceramics was performed. Based on experiments performed the experimental conditions of solid-state reaction of Eu2O3 with Ti2O3, resp. TiO2 leading to single phase EuTiO3 were established. Balk EuTiO3 ceramics were prepared by means of cold isostatic pressing and sintering in reduction atmosphere. This ceramics is suitable for further evaluation of electromagnetic properties.
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The Structure and Properties of Cast Ceramic EUCOR
Klimentová, Jiřina ; Trunec, Martin (referee) ; Pavloušková, Zina (advisor)
The diploma thesis deals with cast ceramics EUCOR which can be described as three-phase system, composed of corundum, baddelyite and a glassy phase. The study was focused on the analysis of structure and phase composition of the material, together with the assessment of their influence on the basic mechanical characteristics. The techniques of light and scanning electron microscopy were used together with energy-dispersive microanalysis, X-ray diffraction and microhardness measurement.
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Bioceramic Materials and Their Biocopatibility with Bone Tissues
Novotná, Lenka ; Trunec, Martin (referee) ; Cihlář, Jaroslav (advisor)
The thesis concerns the study of ceramic coatings of zirconia nanoparticles deposited on alumina, zirconia and glass substrates by ultrasonic spraying. The quality of deposits was investigated in dependence on the type of substrate (composition, temperature, roughness) and concentration of ceramic suspension. The best results were received by the deposition of suspension of low concentration on rough substrates at low temperatures. The biocompatibility was tested in vitro. Good cytocompatibility of ceramics with nanostructure coatings was found.
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