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Optimisation of fibre-matrix interface in ceramic matrix composite
Halasová, Martina ; Černý,, Martin (referee) ; Chlup, Zdeněk (advisor)
This thesis is concerned to the study of behaviour of fibre composites with ceramics matrix. The composite consists of pyrolysed polysiloxane matrix reinforced by ceramic fibre Nextel 720. Main aim of this work is optimisation of fibre matrix interface through the selection of suitable precursor of the matrix with respect to temperature stability, sufficient strength and reasonable fracture toughness. Samples of matrices were exposed to the long term heat treatment in the range 1100 – 1500 °C. The mechanical properties as hardness and indentation elastic modulus were determined after heat treatment. Selected precursors of matrices were used for composite fabrication. Elastic modulus and fracture toughness at room and elevated temperatures were studied. Discussion is dedicated to the description of changes in mechanical properties with respect to chemical processes taking place during high temperature exposition. Further, reasons of fracture behaviour of composite materials are discussed, and finally, gained knowledge and outlined possibilities of subsequent development are summarised.
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Glass-ceramic composite biomaterials
Žaludek, Jakub ; Hadraba, Hynek (referee) ; Drdlík, Daniel (advisor)
The bachelor thesis is focused on the preparation of bioglass 45S5 and composites containing bioglass 45S5 and alumina or zirconia fibres in amount of 1, 3 and 5 wt% by slip-casting method from aqueous and 2-propanolic suspensions. The materials prepared were characterised in term their porosity, relative density, high temperature dilatometry, X-ray diffraction analysis, microstructure and hardness. The slip-casting method produced porous samples which is promising result for a possible biomedical application. The high temperature dilatometry identified three stages of the sintering process and a shrinkage of ~40% of the bioglass-based materials was measured. The crystalline phase of Na2Ca2Si3O9 was created at the sintering temperature of 1050°C but the dissolution of Al2O3 or ZrO2 fibres into the bioglass matrix was not confirmed using the X-ray diffraction analysis. It was found that the hardness of the samples decreased with the amount of the fibres in the materials which was caused by their increasing porosity and large clusters of fibres.
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Glass-ceramic composite biomaterials
Žaludek, Jakub ; Hadraba, Hynek (referee) ; Drdlík, Daniel (advisor)
The bachelor thesis is focused on the preparation of bioglass 45S5 and composites containing bioglass 45S5 and alumina or zirconia fibres in amount of 1, 3 and 5 wt% by slip-casting method from aqueous and 2-propanolic suspensions. The materials prepared were characterised in term their porosity, relative density, high temperature dilatometry, X-ray diffraction analysis, microstructure and hardness. The slip-casting method produced porous samples which is promising result for a possible biomedical application. The high temperature dilatometry identified three stages of the sintering process and a shrinkage of ~40% of the bioglass-based materials was measured. The crystalline phase of Na2Ca2Si3O9 was created at the sintering temperature of 1050°C but the dissolution of Al2O3 or ZrO2 fibres into the bioglass matrix was not confirmed using the X-ray diffraction analysis. It was found that the hardness of the samples decreased with the amount of the fibres in the materials which was caused by their increasing porosity and large clusters of fibres.
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Optimisation of fibre-matrix interface in ceramic matrix composite
Halasová, Martina ; Černý,, Martin (referee) ; Chlup, Zdeněk (advisor)
This thesis is concerned to the study of behaviour of fibre composites with ceramics matrix. The composite consists of pyrolysed polysiloxane matrix reinforced by ceramic fibre Nextel 720. Main aim of this work is optimisation of fibre matrix interface through the selection of suitable precursor of the matrix with respect to temperature stability, sufficient strength and reasonable fracture toughness. Samples of matrices were exposed to the long term heat treatment in the range 1100 – 1500 °C. The mechanical properties as hardness and indentation elastic modulus were determined after heat treatment. Selected precursors of matrices were used for composite fabrication. Elastic modulus and fracture toughness at room and elevated temperatures were studied. Discussion is dedicated to the description of changes in mechanical properties with respect to chemical processes taking place during high temperature exposition. Further, reasons of fracture behaviour of composite materials are discussed, and finally, gained knowledge and outlined possibilities of subsequent development are summarised.
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