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Sintering of Advanced Cubic Ceramic Materials
Hrubý, Jan ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
This bachelor's thesis deals with the literature search on preparation of advanced ceramic materials. It compares the sintering and properties of cubic ceramics with ceramic materials with different crystal structures. The experimental section is devoted to preparing tetragonal ZrO2 ceramic (doped with 3 mol% Y2O3) and cubic ZrO2 ceramic (doped with 8 mol% Y2O3). These ceramics were prepared using two-step sintering combining pressure-less sintering with hot isostatic pressing (HIP). The goal was to prepare dense ceramics with homogenous microstructure. Another studied material was Y2O3 with micrometer sized particles. Microstructure and optical properties of studied materials were evaluated.
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Study of sintering of advanced ceramic materials
Stromský, Tomáš ; Hadraba, Hynek (referee) ; Maca, Karel (advisor)
The influence of various pressure-less heating schedules (CRH - Constant Rate of Heating, TSS - Two Step Sintering, RCS – Rate Controlled Sintering) on the final microstructure of cubic zirconia ceramics was studied in this master´s thesis. There were used nanopowders ZrO2 (stabilized with 8 mol.% Y2O3) with initial particle size 80 nm (TZ-8Y) and 140 nm (TZ-8YSB). Powders were cold isostatically pressed and pressure-less sintered in air by different heating regimes. It was found that for both studied materials the modification of conventional sintering (CRH) using lower sintering temperatures and longer sintering dwell times can result in samples with finer microstructure. For example, the sintering of TZ-8YSB ceramics at a relatively low temperature (1270 °C) but for very long time (60 h) led to ceramics with the same final density (99,25 % of theoretical density) and almost identical grains (1,31 m vs. 1,27 m) in compare with TSS (1440 °C/ 1290 °C/ 15 h). On the other hand, RCS method showed no positive effect on the microstructure of both materials in comparison with CRH method. The obtained results indicate that the microstructure of c-ZrO2 ceramics can be influenced rather in its third sintering stage (by CRH and TSS methods) than in the second sintering stage (by RCS method).
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Study of sintering of advanced ceramic materials
Stromský, Tomáš ; Hadraba, Hynek (referee) ; Maca, Karel (advisor)
The influence of various pressure-less heating schedules (CRH - Constant Rate of Heating, TSS - Two Step Sintering, RCS – Rate Controlled Sintering) on the final microstructure of cubic zirconia ceramics was studied in this master´s thesis. There were used nanopowders ZrO2 (stabilized with 8 mol.% Y2O3) with initial particle size 80 nm (TZ-8Y) and 140 nm (TZ-8YSB). Powders were cold isostatically pressed and pressure-less sintered in air by different heating regimes. It was found that for both studied materials the modification of conventional sintering (CRH) using lower sintering temperatures and longer sintering dwell times can result in samples with finer microstructure. For example, the sintering of TZ-8YSB ceramics at a relatively low temperature (1270 °C) but for very long time (60 h) led to ceramics with the same final density (99,25 % of theoretical density) and almost identical grains (1,31 m vs. 1,27 m) in compare with TSS (1440 °C/ 1290 °C/ 15 h). On the other hand, RCS method showed no positive effect on the microstructure of both materials in comparison with CRH method. The obtained results indicate that the microstructure of c-ZrO2 ceramics can be influenced rather in its third sintering stage (by CRH and TSS methods) than in the second sintering stage (by RCS method).
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Sintering of Advanced Cubic Ceramic Materials
Hrubý, Jan ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
This bachelor's thesis deals with the literature search on preparation of advanced ceramic materials. It compares the sintering and properties of cubic ceramics with ceramic materials with different crystal structures. The experimental section is devoted to preparing tetragonal ZrO2 ceramic (doped with 3 mol% Y2O3) and cubic ZrO2 ceramic (doped with 8 mol% Y2O3). These ceramics were prepared using two-step sintering combining pressure-less sintering with hot isostatic pressing (HIP). The goal was to prepare dense ceramics with homogenous microstructure. Another studied material was Y2O3 with micrometer sized particles. Microstructure and optical properties of studied materials were evaluated.
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