Academic literature on the topic 'Zirconium oxide – Defects'
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Journal articles on the topic "Zirconium oxide – Defects"
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Dunyushkina, Liliya, Adelya Khaliullina, Anastasia Meshcherskikh, Alexander Pankratov, and Denis Osinkin. "Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO3." Materials 12, no. 8 (April 17, 2019): 1258. http://dx.doi.org/10.3390/ma12081258.
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The effect of Sr-nonstoichiometry on phase composition, microstructure, defect chemistry and electrical conductivity of SrxZrO3−δ and SrxZr0.95Y0.05O3−δ ceramics (SZx and SZYx, respectively; x = 0.94–1.02) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy followed by distribution of relaxation times analysis of impedance data. It was shown that at low Sr deficiency (x > 0.96 and 0.98 for SZx and SZYx, respectively) a solid solution of strontium vacancies in strontium zirconate crystal structure forms, whereas at higher Sr deficiency the secondary phase, zirconium oxide or yttrium zirconium oxide, is precipitated. Yttrium solubility limit in strontium zirconate was found to be close to 2 mol%. Y-doped strontium zirconates possess up to two orders of magnitude higher total conductivity than SZx samples. A-site nonstoichiometry was shown to have a significant effect on the electrical conductivity of SZx and SZYx. The highest total and bulk conductivity were observed at x = 0.98 for both systems. Increasing the conductivity with a rise in humidity indicates that proton conduction appears in the oxides in wet conditions. A defect model based on consideration of different types of point defects, such as strontium vacancies, substitutional defects and oxygen vacancies, and assumption of Y ions partitioning over Zr and Sr sites was elaborated. The proposed model consistently describes the obtained data on conductivity.
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Oh, Jiwon, Giwon Seo, Jaehwan Kim, Seungmuk Bae, Jeong-Woo Park, and Jin-Ha Hwang. "Plasma-Enhanced Atomic Layer Deposition of Zirconium Oxide Thin Films and Its Application to Solid Oxide Fuel Cells." Coatings 11, no. 3 (March 22, 2021): 362. http://dx.doi.org/10.3390/coatings11030362.
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Zirconium oxides were deposited using plasma-enhanced atomic layer deposition (PEALD) involving (2-(N-methylamino)1-MethylEthyleneCyclopentadienyl)Bis(DiMethylAmino)Zr (abbreviated as CMEN-Zr) and oxygen plasma as zirconium and oxygen sources. The zirconium oxide thin films demonstrate temperature-independent growth rates per cycle of 0.94 A/cycle at 150–215 °C. The deposited ZrO2 thin films were characterized using numerous analytical tools, i.e., X-ray photoelectron spectroscopy for chemical bonding state and composition, X-ray diffraction for crystallinity, atomic force microscopy for surface morphology, field-emission scanning electron microscopy for cross-sectional analysis, spectroscopic ellipsometry and UV–visible spectrophotometry for optical characterization, capacitance–voltage measurements for dielectric constants and atomic defects, and current–voltage characteristics for electrical information. The insulating features of the crystalline and stoichiometric ZrO2 films were implemented in the anode composites to evaluate the influence of ALD-based nano-features on the electrochemical performance of solid oxide fuel cells, with the main emphasis on anode performance. The presence of nanomaterials on Ni/YSZ anode composites is analyzed to determine the negative effects on electrochemical performance and the degradation of cell performance of solid oxide fuel cells (SOFCs). The artificial design was proven to be effective in controlling the cell performance as long as proper material design was adopted in SOFC electrodes.
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Park, Areum, Pyungho Choi, Woojin Jeon, Donghyeon Lee, Donghee Choi, and Byoungdeog Choi. "Defect Analysis and Reliability Characteristics of (HfZrO4)1−x(SiO2)x High-κ Dielectrics." Journal of Nanoscience and Nanotechnology 20, no. 11 (November 1, 2020): 6718–22. http://dx.doi.org/10.1166/jnn.2020.18791.
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Hafnium zirconium silicon oxide ((HfZrO4)1−x(SiO2)x) materials were investigated through the defect analysis and reliability characterization for next generation high-κ dielectric. Silicate doped hafnium zirconium oxide (HfZrO4) films showed a reduction of negative flat-band voltage (Vfb) shift compared to pure HfZrO4. This result was caused by a decrease in donor-like interface traps (Dit) and positive border traps (Nbt). As the silicon oxide (SiO2) content increased, the Vfb was shifted in the positive direction from −1.23 to −1.10 to −0.91 V and the slope of the capacitance–voltage (C–V) curve increased. The nonparallel shift of the C–V characteristics was affected by the Dit, while the Nbt was responsible for the parallel C–V curve shift. The values of Dit reduced from 4.3 × 1011, 3.5 × 1011, and 3.0 × 1011 cm−2eV−1, as well as the values of Nbt were decreased from 5.24, 3.90 to 2.26 × 1012 cm−2. Finally, reduction of defects in the HfZrO4-base film with an addition of SiO2 affected the gate oxide reliability characteristics, such as gate leakage current (JG), bias temperature stress instability (BTSI), and time dependent gate dielectric breakdown (TDDB).
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Sousa, W. S. C. de, D. M. A. Melo, J. E. C. da Silva, R. S. Nasar, M. C. Nasar, and J. A. Varela. "Photoluminescence in ZrO2 doped with Y and La." Cerâmica 53, no. 325 (March 2007): 99–103. http://dx.doi.org/10.1590/s0366-69132007000100015.
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This study aims to describe the synthesis and optical characterization of a nanometric zirconium oxide solid solution containing yttrium and lanthanum. Zirconium citrate, yttrium nitrate and lanthanum nitrate were mixed in the ratios: 94 mol% of ZrO2 - 6 mol% of Y2O3 and 92 mol% of ZrO2 - 6 mol % of Y2O3 - 2 mol % of La2O3. FTIR analysis shows organic material in decomposition and thermal analysis shows the transformation from the tetragonal to the monoclinic phase of zirconia, the loss of water molecule and zirconium dehydroxylation. The X-ray diffraction analysis shows a homogeneous phase formation of ZrO2-Y2O3-La2O3 demonstrating that lanthanum addition does not cause phase formation, promoting a solid solution based on zirconia with cubic structure. The photoluminescence spectra show absorption bands at 562 nm and 572 nm (350 °C) and specific absorption bands at 543 nm, 561 nm, 614 nm and 641 nm (900 °C). The photoluminescence effect at low temperature is caused by defects such as (Y Zr,Y O)', (2Y Zr,V O)'' and V O. Emissions at 614 nm and 641 nm are caused by O-2p -> Zr-4d transition. An emission at 543 nm can be attributed to LaO8 centers with O-2p -> La-5d transition.
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Volodin, Alexander M., Vladimir O. Stoyanovskii, Vladimir I. Zaykovskii, Roman M. Kenzhin, and Aleksey A. Vedyagin. "The Features of a High-Temperature Synthesis of ZrO2 in a Core-Shell ZrO2@C Structure." Materials Science Forum 950 (April 2019): 133–37. http://dx.doi.org/10.4028/www.scientific.net/msf.950.133.
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Zirconium oxide was obtained via traditional precipitation from a ZrOCl2 solution with ammonia followed by drying at 110 °C. The carbon-coated samples were synthesized by calcination of the pristine zirconia mixed with polyvinylalcohol. The obtained ZrO2@C samples of core-shell structure as well as the reference samples of pristine zirconia were calcined at different temperatures from 500 to 1400 °C. All the materials were examined by a set of physicochemical methods (a low-temperature argon adsorption, transmission electron microscopy, X-ray diffraction analysis, photoluminescence spectroscopy). It was found that the carbon coating prevents the sintering of the oxide nanoparticles, which allows one to maintain the specific surface area, the size of the oxide core and, finally, stabilize its phase composition. Transformation of the cubic phase into monoclinic phase becomes significantly complicated. Thus, 40% of the cubic phase was detected even after calcination of the ZrO2@C sample at 1400 °C. Moreover, the carbon-coated samples treated at elevated temperatures with subsequent removal of the carbon shell were found to possess the highest concentration of the defects related to a presence of the anion vacancies in zirconia.
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Tsuchiya, Bun, S. Nagata, Kesami Saito, Kentaro Toh, and Tadaaki Shikama. "Electrical Property of Calcium-Zirconium-Indium Oxide by Irradiation." Materials Science Forum 480-481 (March 2005): 579–84. http://dx.doi.org/10.4028/www.scientific.net/msf.480-481.579.
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Radiation induced changes in electrical properties of calcium-zirconium-indium oxide ceramics (CaZr0.9In0.1O3-d) were investigated using a fission reactor of Japan Materials Testing Reactor (JMTR). Electrical conductivity of CaZr0.9In0.1O3-d under the reactor irradiation increased by the Radiation Induced Conductivity (RIC), Radiation Induced Electromotive Force (RIEMIF)and Radiation Induced Electrical Degradation (RIED), caused by the electronic excitation. The RIC and the RIEMF decreased gradually for the constant value of the reactor power with the increase of irradiation time. Moreover, it was confirmed by Post-irradiation Examination (PIE) experiments that the initial electrical and thermal properties were completely degraded by the irradiation. These radiation effects are attributed to point defects or their clusters produced by atomic displacements caused by neutron collisions and also by the radiolysis.
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Zhang, Lina, Liang-Yu Chen, Cuihua Zhao, Yujing Liu, and Lai-Chang Zhang. "Calculation of Oxygen Diffusion Coefficients in Oxide Films Formed on Low-Temperature Annealed Zr Alloys and Their Related Corrosion Behavior." Metals 9, no. 8 (August 2, 2019): 850. http://dx.doi.org/10.3390/met9080850.
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The growth of oxide film, which results from the inward oxygen diffusion from a corrosive environment, is a critical consideration for the corrosion resistance of zirconium alloys. This work calculates the oxygen diffusion coefficients in the oxide films formed on zirconium alloys annealed at 400~500 °C and investigates the related corrosion behavior. The annealed samples have a close size for the second-phase particles but a distinctive hardness, indicating the difference in substrate conditions. The weight gain of all samples highly follows parabolic laws. The weight gain of the sample annealed at 400 °C has the fastest increase rate at the very beginning of the corrosion test, but its oxide film has the slowest growth rate as the corrosion proceeds. By contrast, the sample annealed at 500 °C shows the lowest weight gain but the highest corrosion rate constant. Such a corrosion behavior is attributed to the amount of defects existing in the oxide film formed on the annealed samples; fewer defects would provide a lower fraction of short-circuit diffusion in total diffusion, resulting in a lower diffusion coefficient of oxygen in the oxide film, thereby producing better corrosion resistance. This is consistent with the calculated diffusion coefficients of oxygen in the oxide films: 3.252 × 10−11 cm2/s, 3.464 × 10−11 cm2/s and 3.740 × 10−11 cm2/s for the samples annealed at 400 °C, 450 °C, and 500 °C, respectively.
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Raza, Mohsin, Simone Sanna, Lucia dos Santos Gómez, Eric Gautron, Abdel Aziz El Mel, Nini Pryds, Rony Snyders, Stéphanos Konstantinidis, and Vincenzo Esposito. "Near interface ionic transport in oxygen vacancy stabilized cubic zirconium oxide thin films." Physical Chemistry Chemical Physics 20, no. 41 (2018): 26068–71. http://dx.doi.org/10.1039/c8cp05465g.
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Terada, Yayoi, and Tetsuo Mohri. "Oxygen Migration and Local Structural Changes with Schottky Defects in Pure Zirconium Oxide Crystals." Journal of the Physical Society of Japan 87, no. 5 (May 15, 2018): 054801. http://dx.doi.org/10.7566/jpsj.87.054801.
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Ovsyannikov, Boris V. "Beware of Grain Refinement." Materials Science Forum 794-796 (June 2014): 143–48. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.143.
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Recently significant successes have been achieved in the field of grain refinement by means of such additives as the titanium, zirconium, scandium, AlTiB and AlTiC. However, introduction of grain refining additives results to a number of negative effects. These effects can be divided into four basic groups: 1. Reduction of high-strength alloy casting properties. 2. Defects of structure. 3. Intermetallic and oxide inclusions. 4. Decrease in mechanical and fatigue properties of the semis made of ingots with fine grain.
Dissertations / Theses on the topic "Zirconium oxide – Defects"
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Youssef, Mostafa Youssef Mahmoud. "Predicting the equilibria of point defects in zirconium oxide : a route to understand the corrosion and hydrogen pickup of zirconium alloys." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87492.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 172-178).
The performance of zirconium alloys in nuclear reactors is compromised by corrosion and hydrogen pickup. The thermodynamics and kinetics of these two processes are governed by the behavior of point defects in the ZrO₂ layer that grows natively on these alloys. In this thesis, we developed a general, broadly applicable framework to predict the equilibria of point defects in a metal oxide. The framework is informed by density functional theory and relies on notions of statistical mechanics. Validation was performed on the tetragonal and monoclinic phases of ZrO₂ by comparison with prior conductivity experiments. The framework was applied to four fundamental problems for understanding the corrosion and hydrogen pickup of zirconium alloys. First, by coupling the predicted concentrations of oxygen defects in tetragonal ZrO₂ with their calculated migration barriers, we determined oxygen self-diffusivity in a wide range of thermodynamic conditions spanning from the metal-oxide interface to the oxide-water interface. This facilitates future macro-scale modeling of the oxide layer growth kinetics on zirconium alloys. Second, using the computed defect equilibria of the tetragonal and monoclinic phases, we constructed a temperature-oxygen partial pressure phase diagram for ZrO₂. The diagram showed that the tetragonal phase can be stabilized below its atmospheric transition-temperature by lowering the oxygen chemical potential. This work adds a new explanation to the stabilization of the tetragonal phase at the metal-oxide interface where the oxygen partial pressure is low. Third, using the developed framework, we modeled co-doping of monoclinic ZrO₂ with hydrogen and a transition metal. Our modeling predicted a volcano-like dependence of hydrogen (proton) solubility on the first-row transition metals, which is consistent with a set of systematic experiments from the nuclear industry. We discovered that the reason behind this behavior is the ability of the transition metal to p-type-dope ZrO₂ and hence lower the chemical potential of electron. Therefore, the peak of the hydrogen solubility in monoclinic ZrO₂ also corresponds to an increased barrier for hydrogen gas evolution on the surface. This explanation opens the door to physics-based design of resistant zirconium alloys, and qualitatively consistent with the monoclinic ZrO₂. Finally, we uncovered the interplay between certain hydrogen defects and planar compressive stress which tetragonal ZrO₂ experiences on zirconium alloys. The stress enhances the abundance of these defects, while these same defects tend to relax the stress. This interplay was used to propose an oxide fracture mechanism by which hydrogen is picked up.
by Mostafa Youssef Mahmoud Youssef.
Ph. D.
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Holz, Laura Isabel Vilas. "Yttria-stabilized Zirconia with beige colour." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21874.
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Mestrado em Engenharia de MateriaisA Zircónia é um cerâmico avançado que se tem destacado como um material versátil e promissor, apresentando uma combinação interessante de propriedades térmicas, elétricas, óticas e mecânicas, pouco comuns nos materiais cerâmicos, sendo por isso utilizada em diversas aplicações. A empresa INNOVNANO produz pós de Zircónia com diferentes características e atualmente tem clientes interessados em cerâmicos à base de Zircónia estabilizada com ítria de coloração bege com propriedades mecânicas específicas. Assim, o trabalho realizado neste estágio pretendeu desenvolver um material que cumpra os requisitos solicitados, tendo como referência uma amostra cedida por um cliente da INNOVNANO cuja cor se pretendia reproduzir, mas cuja composição e processamento eram desconhecidos. Deste modo, o trabalho teve início com a caracterização da amostra de referência através de Microscopia Eletrónica de Varrimento, Difração de raios X, espectroscopia de Raman, Fotoluminescência e Refletância Difusa de modo a permitir compreender o mecanismo de coloração, o qual mostrou ser baseado em defeitos estruturais, desenvolvidos em condições redutoras. A introdução de defeitos extrínsecos pela dopagem com óxido de ferro (Fe2O3) na matriz da Zircónia estabilizada com 2 mol % de ítria (2YSZ) foi a alternativa selecionada para a reprodução da cor solicitada. As amostras foram estudadas do ponto de vista microestrutural, estrutural e ótico. A dopagem com óxido de ferro revelou ser um mecanismo de coloração adequado, reprodutível e irreversível, permitindo o desenvolvimento de um material cromaticamente estável no que concerne à sua utilização em diferentes condições de processamento, tais como diferentes atmosferas e intervalos de temperatura. A estabilidade da cor foi confirmada com tratamentos térmicos em atmosferas oxidantes e redutoras. O efeito da adição do dopante nas propriedades mecânicas da Zircónia foi estudado, avaliando-se a tenacidade à fratura (KIC), a dureza de Vickers (HV10) e a resistência à flexão (σflexural) em amostras com elevado teor de Zircónia tetragonal ( >92 %) e com elevada densidade relativa ( >96%). Os materiais desenvolvidos preenchem os requisitos previamente definidos pela INNOVNANO, tendo-se observado, contudo, um ligeiro decréscimo da tenacidade à fratura com a adição de dopante. Já a dureza Vickers e a resistência à flexão não foram significativamente afetadas pela adição de Fe2O3.
Zirconia is a very versatile advanced ceramic that offers an interesting combination of thermal, chemical, electrical, mechanical and optical properties which are uncommon to find in ceramic materials and therefore is used in several applications. INNOVNANO is one of the main Zirconia powders suppliers in the market with potential clients for beige YSZ ceramics with specific mechanical properties. Thus, the work performed during this internship aimed to develop a material that meets the requested requirements, having as reference a sample provided by an INNOVNANO’s client which colour was intended to be reproduced but which composition and processing were unknown. In this way, the work began with reference material characterization through Scanning Electron Microscopy, X-ray Diffraction, Raman Spectroscopy, Photoluminescence and Diffuse Reflectance in order to understand the colouring mechanism, which was shown to be based on structural defects developed under reducing conditions. The introduction of extrinsic defects by doping with iron oxide (Fe2O3) in the matrix of 2 mol % yttria-stabilized Zirconia (2YSZ) was the alternative selected for the reproduction of the requested colour. The samples were studied from the microstructural, structural and optical point of view. Doping with iron oxide has proved to be a suitable, reproducible and irreversible colouring mechanism allowing the development of a chromatically stable material with respect to its use in different processing conditions such as different atmospheres and temperature ranges. Colour stability was proved by thermal treatments in oxidizing and reducing atmospheres. The effect of dopant addition on the mechanical properties of Zirconia was studied by evaluating the fracture toughness (KIC), Vickers hardness (HV10) and flexural strength (σflexural) in samples with high tetragonal Zirconia content (> 92%) and high relative density (> 96%). The developed material fulfils the requirements previously defined by INNOVNANO, but a slight decrease of the fracture toughness with the addition of dopant was observed while Vickers hardness and flexural strength were not significantly affected by the addition of Fe2O3.
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Fabris, Stefano. "Atomistic modelling of phase transitions in zirconia." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322848.
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Zacate, Matthew O. "A microscopic study of the interaction between aliovalent dopants and native defects in group IV oxides : indium and cadmium in ceria and zirconia." Thesis, 1997. http://hdl.handle.net/1957/34309.
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In order to understand better the defect structure and dynamics associated
with lower valent dopants complexed with native defects in group IV oxides, In/Cd
perturbed angular correlation spectroscopy was performed in ceria and zirconia. Examining
the orientation symmetry axis of defects in ceria single crystals at low temperature
has allowed the identification of a cadmium with a bound near-neighbor
oxygen-vacancy complex as well as a complex involving a cadmium with two opposing,
near-neighbor oxygen vacancies. The orientation of the symmetry axis of a third
complex is reported; however, this information is not sufficient to identify it. Complementing
these low temperature studies, the dynamics of the cadmium/oxygen-vacancy
interaction in zirconia at high temperatures was studied. The motion of the oxygen
vacancy at high temperatures results in a damping of the PAC signal. This damping
is not well characterized by the heuristic Marshall-Meares PAC fitting function, and
a model is proposed to fit the data in terms of three physical parameters associated
with the vacancy's motion. These parameters are the rate at which a bound oxygen
vacancy hops among equivalent sites about the probe, the rate at which a bound
vacancy detraps, and the rate at which a vacancy is trapped by cadmium. Fits of
individual spectra using this model give respective activation energies of 0.3-0.6 eV,
0.9-1.6 eV, and 0.4-0.6 eV. The uncertainty in these energies can most likely be
reduced by fitting spectra from multiple temperatures simultaneously. Despite the
large uncertainty in the fitted energies, the values are physically reasonable and indicate
that the model adequately describes the motion of the oxygen vacancy about
cadmium.Graduation date: 1997
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Alves, Mauro A. "The dynamics of oxygen vacancies in zirconia : an analysis Of PAC data." Thesis, 2003. http://hdl.handle.net/1957/30128.
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Nuclear techniques such as perturbed angular correlation (PAC) sample the
hyperfine interactions of a large number of probe atoms in specific crystallographic
sites. Real crystals contain static defects producing a distribution
of electric field gradients (EFGs) that add to the ideal EFG of the crystal at
any given probe site. Also, dynamic defects like moving vacancies and interstitial
atoms can be present in the crystal and contribute to the distribution
of EFGs. The distribution of EFGs leads to line broadening and a change in
the observed asymmetry parameter η since the total EFG no longer has the
symmetry of the perfect crystal. When both defects are present in a material,
obtaining quantitative information from the analysis of PAC spectra is usually very difficult since great care has to be taken to ensure that the source
of line broadening is identified correctly. In order to relate the relationship
between the static line broadening and changes in the asymmetry parameter
η, a uniform random distribution of point charges was used to simulate the
static defect EFG. PAC spectra collected on cubic niobium metal, cubic stabilized
zirconia and Nb-doped tetragonal zirconia were fitted with this model.
Although the quality of the fits is good, more work is needed to clarify the
relationship between the new model parameters and the line broadening and
asymmetry parameter derived from conventional model fits. The PAC spectra
of Nb-doped tetragonal zirconia were fitted with a conventional static model
to establish a reliable relationship between line broadening and the asymmetry
parameter when only static defects are present in a sample. To account for effects
of dynamic defects, a four state stochastic model for vacancy motion was
adapted in order to include the line broadening and changes in the asymmetry
produced by static defects. As a result, the activation energies corresponding
to the rates at which a oxygen vacancy is trapped by, detraps from, and hops
among equivalent sites about a PAC probe atom were calculated. The values
that were found are physically reasonable, indicating that the dynamics of an
oxygen vacancy around a PAC probe atom are satisfactorily described.Graduation date: 2003
Books on the topic "Zirconium oxide – Defects"
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Zacate, Matthew O. A microscopic study of the interaction between aliovalent dopants and native defects in group IV oxides: Indium and cadmium in ceria and zirconia. 1997.
Find full textConference papers on the topic "Zirconium oxide – Defects"
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Park, Pilyeon, Mirna Urquidi-Macdonald, and Digby D. Macdonald. "Application of the PDM (Point Defect Model) to the Oxidation of Zircaloy Fuel Cladding in Water-Cooled Nuclear Reactors." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49098.
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The PDM [Point Defect Model, D. D. Macdonald, Pure Appl. Chem., 71, 951 (1999)] describes the corrosion of passive metals in aqueous media in terms of the generation and annihilation of point defects at the passive film interfaces. In the current work, we have modified the PDM to provide a comprehensive, atomic scale description of the growth of bilayer passive films on zirconium to simulate the corrosion of Zircaloy fuel cladding in BWRs and PWRs under high burn-up conditions. Two models have been formulated; one comprising a hydride inner (barrier) layer and an oxide outer layer and other comprising an oxide inner layer and an oxide outer layer for PWR and BWR cladding, respectively. Since there are currently no experimental data for the kinetics of defect generation and annihilation at the passive film interfaces for Zircaloys under PWR/BWR conditions, of the type that are required for this analysis, this paper focuses only on exploring and predicting trends in the corrosion behavior of Zircaloy by using prototypical values for various electrochemical parameters. We derive equations for predicting the barrier layer thickness as a function of the applied voltage, pH, porosity, and temperature for both BWR and PWR primary water chemistry conditions.
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Yurchenko, L., I. Bykov, A. Vasylyev, V. Vereshchak, G. Suchaneck, L. Jastrabik, and A. Dejneka. "Defect structure of zirconium oxide nanosized powders with Y2O3, Sc2O3, Cr2O3 impurities." In 2012 IEEE International Conference on Oxide Materials for Electronic Engineering (OMEE). IEEE, 2012. http://dx.doi.org/10.1109/omee.2012.6464776.
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Huang, Xiao. "Effect of Co-Doping on Microstructure, Thermal and Mechanical Properties of Ternary Zirconia-Based Thermal Barrier Coating Materials." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59007.
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7YSZ (yttria stabilized zirconia) was co-doped with metal oxides of different valence, ionic radius and mass in order to investigate microstructural and property changes as a result of co-doping. Mechanical alloying process was used to produce the powder blends which were subsequently sintered at 1500°C for 120 hours. The results from SEM, XRD and DSC showed that the microstructures of the co-doped ternary oxides were affected by the amount of oxygen vacancies in the system, the co-dopant cation radius and mass. Increasing the number of oxygen vacancies by the addition of trivalent co-dopant (Yb2O3 and Sc2O3) as well as the use of larger cations promoted the stabilization of cubic phase. The tetravalent co-dopant (CeO2), on the other hand, had the effect of stabilizing tetragonal phase which may transform into monoclinic phase during cooling, depending on the concentration of tetravalent co-dopant and the mass. Smaller cation mass had the effect of reducing the transformation temperature from tetragonal to monoclinic phase. Pentavalent co-dopants (Nb2O5 and Ta2O5) were found to stabilize the tetragonal phase at high temperature; however, the stability of the tetragonal phase upon cooling was determined by the mass and ionic radius of the co-dopants. Cation clustering was observed during cooling in trivalent oxide co-doped 7YSZ while clustering of trivalent and pentavalent cations in pentavalent co-doped 7YSZ was not detected. Additionally, from the thermal conductivity measurement results, it was found that trivalent oxides exhibited the most significant effect on reducing the thermal conductivity of ternary oxides; this trend was followed by pentavalent co-doping oxides whereas the tetravalent CeO2 co-doped 7YSZ showed marginal effect. A semi-empirical thermal conductivity model was established based on defect cluster model and the predicted room temperature thermal conductivity values were found to be consistent with that measured experimentally. Furthermore, the incorporation of co-dopant oxide in 7YSZ was observed to substantially modify the elastic modulus of the ternary oxides. More specifically, the addition of co-dopant with larger cation radius was found to reduce the elastic modulus of 7YSZ due to the increase in lattice parameter(s).