Development, characterization and creep resistance of cubic zirconia doped with rare earth oxides processed through spark plasma sintering
department or school: Applied Science, Faculty of
department or school: Engineering, School of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Robles Arellano, Karen Denisse
issued: 2013-05-08T09:13:16Z
issued: 2013
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Development of new technological systems, such as fuel cells or nuclear power generation stations, often relies on the availability of materials whose properties accommodate the operational requirements of the system. Fabrication of creep-resistant ceramic materials is currently receiving worldwide interest due to their potential use in solid oxide fuel cells, thermal barrier coatings and insulators for hostile environments. In this research a novel fabrication process, Spark Plasma Sintering (SPS), was used to prepare cubic Yttria-stabilized Zirconia (YSZ) composites doped with three different rare earth oxides. Specifically, YSZ was doped with 6.4wt%, 12.7 wt% and 18.8 wt% CeO₂; 11.6 wt%, 21.6 wt% and 30.5wt% La₂O₃; and 12wt% and 22 wt% Nd₂O₃. Composites were successfully fabricated using the SPS technique, and the effect of selected parameters on density and grain size was studied. The novel composites were characterized using Scanning Electron Microscope –X-Ray Energy Dispersive Spectroscopy (SEM-XEDS), X-Ray Diffraction (XRD) and Optical Microscopy (OM). Also, compressive creep testing was performed and the active creep deformation mechanisms were studied. The results reveal that increasing the sintering temperature resulted in grain growth in all the composites. Addition of the rare earth oxides had a strong grain refinement effect on YSZ. Further, addition of La₂O₃ and Nd₂O₃ resulted in formation of a bimodal microstructure. In contrast, the effect of variation of dopant wt% on the grain size and relative density of the composites could not be established. Compressive creep tests in the temperature range of 1200-1330°C were carried out for YSZ, 6.4wt% CeO₂–YSZ and 11.6wt% La₂O₃ –YSZ composites. The stress exponent for all composites ranged between 1.2-2.7. The activation energy was ~730 kJ/mol for YSZ, ~490 kJ/mol for 6.4wt% CeO₂–YSZ and ~566 kJ/mol for 11.6wt% La₂O₃ –YSZ. These values of n and Q suggest that creep deformation was primarily accommodated by gr…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/44442
note: DEVELOPMENT, CHARACTERIZATION AND CREEP RESISTANCE OF CUBIC ZIRCONIA DOPED WITH RARE EARTH OXIDES PROCESSED THROUGH SPARK PLASMA SINTERING by Karen Denisse Robles Arellano B. A. Sc., The University of British Columbia, 2011 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) April 2013 © Karen Denisse Robles Arellano, 2013 ii Abstract Development of new technological systems, such as fuel cells or nuclear power generation stations, often relies on the availability of materials whose properties accommodate the operational requirements of the system. Fabrication of creep-resistant ceramic materials is currently receiving worldwide interest due to their potential use in solid oxide fuel cells, thermal barrier coatings and insulators for hostile environments. In this research a novel fabrication process, Spark Plasma Sintering (SPS), was used to prepare cubic Yttria-stabilized Zirconia (YSZ) composites doped with three different rare earth oxides. Specifically, YSZ was doped with 6.4wt%, 12.7 wt% and 18.8 wt% CeO2; 11.6 wt%, 21.6 wt% and 30.5wt% La2O3; and 12wt% and 22 wt% Nd2O3. Composites were successfully fabricated using the SPS technique, and the effect of selected parameters on density and grain size was studied. The novel composites were characterized using Scanning Electron Microscope –X-Ray Energy Dispersive Spectroscopy (SEM-XEDS), X-Ray Diffraction (XRD) and Optical Microscopy (OM). Also, compressive creep testing was performed and the active creep deformation mechanisms were studied. The results reveal that increasing the sintering temperature resulted in grain growth in all the composites. Addition of the rare earth oxides had a strong grain refinement effect on YSZ. Further, addition of La2O3 and Nd2O3 resulted in formation of a bimodal microstructure. In contrast, the effect of variation of dopant …
has type: Thesis/Dissertation
date issued: 2013-11
is shown at: 10.14288/1.0073766
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/44442