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Title:Ceramic interfaces and their radiation response
Author(s):Madden, Nathan James
Director of Research:Krogstad, Jessica A
Doctoral Committee Chair(s):Krogstad, Jessica A
Doctoral Committee Member(s):Perry, Nicola; Averback, Robert; Heuser, Brent
Department / Program:Materials Science & Engineerng
Discipline:Materials Science & Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
In-situ TEM
Abstract:Ceramic materials are useful due to their various properties, making them the material of choice for many different applications. However, in extreme environments such as one that contains radiation, the physics and the material science of how the ceramic materials change still need to be clarified. In this present examination, the behavior of ceramic materials was studied under a variety of irradiation conditions. One aspect of radiation effects that occurs on ceramic systems is changes in the crystal structure. This investigation on the changes in crystal structure that occurs under ion irradiation is observed in two different studies. The first study focuses on 45 MeV gold irradiation into yttria-stabilized zirconia. This study aimed to understand the effect of medium energy irradiation on a traditional stability crystal structure of yttria-stabilized zirconia, the disorder fluorite structure. Oxygen vacancy ordering with a similar motif to the bixbyite structure was observed through electron diffraction within the transmission electron microscopy. Additional experimental characterization techniques, Raman spectroscopy and XPS, were also used to provide more insight into the observed ordering. Moreover, atomic modeling was done by collaborators that validate the observed ordering. The second study focused on the changes in crystallization and amorphization limits as a function of radiation dose. This study uses a pyrochlore structured ceramic, gadolinium titanate, that under ion irradiation amorphized. The observed crystallization temperature and amorphization dose changes as a function of the total irradiation dose. Moreover, the crystallization kinetics were observed to changes as a function of total irradiation dose. Overall, these two studies illustrate the different effects of ion energy and crystal structure on a ceramic’s response to irradiation. The final aspect of radiation effects on ceramic materials examined in this dissertation is the effects of radiation on the microstructure. Two different studies were done to understand the effect of radiation on the microstructure. The first study examined whether grain boundaries or free surfaces are a more effective defect sink. Free surfaces were observed to be a better defect sink when compared to grain boundaries. The second study examined the effect of radiation on nanoparticles under various radiation temperatures and different ion species. The nanoparticles were observed to sinter and characterize the nanoparticles' diffusion using the two-particle sintering model. The most significant conclusion of the nanoparticle study was the different defect mobilities at different temperatures; at low temperatures, the defect mobility is dominated by sink-limit kinetics, whereas at the high temperature, the defect mobility is dominated by recombination-limit kinetics. Overall, the research presented in this dissertation addresses the effect of ion irradiation on ceramics crystal structures and ceramic microstructures. This work highlights the need for careful design of microstructures. Additionally, this work also highlights the opportunities to control the properties of ceramic materials via ion irradiation. These results indicate several promising future directions that can be taken to improve further the understanding of the ion irradiation effect of ceramic systems.
Issue Date:2021-07-14
Rights Information:Copyright 2021 Nathan Madden
Date Available in IDEALS:2022-01-12
Date Deposited:2021-08

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