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Processing and properties of lead free piezoceramic materials
Tásler, Jan ; Částková, Klára (referee) ; Maca, Karel (advisor)
This bachelor thesis deals with the study of lead free piezoceramic materials with comprehensive focus on the material called BCZT. The effect of different milling duration of the ceramic precursors and the effect of sintering temperature of the green body on the relative density and grain size of the final ceramics is studied on the prepared samples of this material with chemical composition of (Ba0,85Ca0,15)(Zr0,1Ti0,9)O3. Also, the effect of microstructure on the piezoelectric properties is examined. Both the milling duration and sintering temperature are key factors which influence the microstructure of ceramics. The effect of microstructure on the piezoelectric properties was confirmed mainly for piezoelectric coefficients d33 and kp.
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Processing and properties of transparent polycrystalline ceramic materials
Tásler, Jan ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
The presented diploma thesis is focused on the preparation and properties of transparent polycrystalline ceramic materials based on Al2O3. Theoretically, the most important technological aspects of the processing of these materials are presented. Detailed attention is given to transparent Al2O3 polycrystalline ceramics doped with rare earth elements. The influence of microstructural parameters on the optical properties (represented by RIT) is investigated on Al2O3 samples doped and codoped with dysprosium, terbium and chromium. A significant effect of the average grain size on the light transmittance of all samples is observed. The highest RIT = 55 % (measured by a laser beam with a wavelength of 632,8 nm) was achieved by an optimized preparation process for a sample doped with 0,05 at. % of dysprosium. For all samples photoluminescent properties are also analysed. The photoluminescent emission spectra correspond to the activation of doping elements. In case of the terbium and chromium codoped samples, the differences in the activation of individual dopants depending on different excitation wavelengths were demonstrated, resulting in different colour emissions for different excitation wavelengths.
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Processing and properties of transparent polycrystalline ceramic materials
Tásler, Jan ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
The presented diploma thesis is focused on the preparation and properties of transparent polycrystalline ceramic materials based on Al2O3. Theoretically, the most important technological aspects of the processing of these materials are presented. Detailed attention is given to transparent Al2O3 polycrystalline ceramics doped with rare earth elements. The influence of microstructural parameters on the optical properties (represented by RIT) is investigated on Al2O3 samples doped and codoped with dysprosium, terbium and chromium. A significant effect of the average grain size on the light transmittance of all samples is observed. The highest RIT = 55 % (measured by a laser beam with a wavelength of 632,8 nm) was achieved by an optimized preparation process for a sample doped with 0,05 at. % of dysprosium. For all samples photoluminescent properties are also analysed. The photoluminescent emission spectra correspond to the activation of doping elements. In case of the terbium and chromium codoped samples, the differences in the activation of individual dopants depending on different excitation wavelengths were demonstrated, resulting in different colour emissions for different excitation wavelengths.
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Processing and properties of lead free piezoceramic materials
Tásler, Jan ; Částková, Klára (referee) ; Maca, Karel (advisor)
This bachelor thesis deals with the study of lead free piezoceramic materials with comprehensive focus on the material called BCZT. The effect of different milling duration of the ceramic precursors and the effect of sintering temperature of the green body on the relative density and grain size of the final ceramics is studied on the prepared samples of this material with chemical composition of (Ba0,85Ca0,15)(Zr0,1Ti0,9)O3. Also, the effect of microstructure on the piezoelectric properties is examined. Both the milling duration and sintering temperature are key factors which influence the microstructure of ceramics. The effect of microstructure on the piezoelectric properties was confirmed mainly for piezoelectric coefficients d33 and kp.
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