Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"Zirconium diboride"”.
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Improving the thermal shock resistance of zirconium diboride ceramics
… on improving the thermal shock resistance of zirconium diboride (ZrB₂) based ceramics. Despite the development of ZrB₂-based materials for their use in high temperature applications, the thermal shock properties have not been investigated extensively. Materials expected to be used in …
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Elevated temperature mechanical properties of zirconium diboride based ceramics
<p>"Research presented in this dissertation focused on the mechanical behavior of ZrB₂ based ceramic at elevated temperatures. Flexure strength, fracture toughness, and elastic modulus were measured at temperatures up to 2300ºC for three compositions: monolithic ZrB₂ (Z); ZrB₂ - 30 vol% SiC - 2 …
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Stress measurement and development of zirconium diboride-silicon carbide ceramics
"Research presented in this dissertation focused on the production of ZrB₂-SiC composites and their characterization; in particular their mechanical properties and thermally generated residual stresses. Thermally generated stresses were measured using Raman spectroscopy as well as both neutron and …
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Densification, microstructure, and mechanical properties of zirconium diboride based ultra-high temperature ceramics
"The first part of this dissertation was aimed at studying the densification of ZrB₂ ceramics by pressureless sintering techniques. Various processes have been applied to coat ZrB₂ powders with polymer precursors, which were used to produce C after charring. After sintering at 1900⁰C, relative …
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Effect of solid solutions and second phases on the thermal conductivity of zirconium diboride ceramics
… aimed at understanding thermal transport in diboride based materials"--Abstract, page iv.</p>
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Processing, microstructure, and mechanical properties of zirconium diboride-molybdenum disilicide ceramics and dual composite architectures
<p>"This research had two objectives: characterization of processing-microstructure-mechanical property relationships of conventional ZrB<sub>2</sub>-MoSi<sub>2</sub> ceramics at room temperature (RT) and 1500⁰C in air, and fabrication of ZrB<sub>2</sub>-MoSi<sub>2</sub> dual composite …
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Neutronic Characteristics of Using Zirconium Diboride and Gadolinium in a Westinghouse 17 X 17 Fuel Assembly
… UO2 fuel pellet is coated with a thin layer of zirconium diboride (ZrB2). Other fuel manufacturers such as Combustion Engineering, Siemens, General Electric, and Framatome incorporate gadolinium directly into the fuel matrix which yields the gadolinium-uranium (Gd2O3 - UO2) integral burnable …
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Reaction processing for the development of ultra-high temperature ceramics
… candidates for these extreme conditions. These diborides have melting temperatures that exceed 3000⁰C, the potential for strength retention at elevated temperatures, and moderate oxidation resistance when compared to high temperature carbides. However, diborides have often been reported to …
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Sintering techniques for microstructure control in ceramics
… were examined in two classes of materials; zirconium diboride ultra high temperature ceramic composites, and all solid lithium-ion battery phosphate materials. ^ Investigation of zirconium diboride ceramics focused on the effects of zirconium carbide as a secondary or tertiary phase in …
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Manufacturing of advanced continuous fiber reinforced composites for high temperature applications
… process to produce ceramic composite material of zirconium diboride-silicon carbide reinforced with continuous silicon carbide fibers for use in ultra high temperature applications. A second process was developed using the dry press ceramic manufacturing technique in conjunction with the polymer …
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Processing to Enable Direct-Write Additive Manufacturing of Ceramics and Ceramic Composites
… future feedstocks to prevent this defect. A zirconium diboride (ZrB<sub>2</sub>) paste (φ = 0.45) was formulated to print fine-featured (<335 >µm), ultra-high temperature ceramic (UHTC) monoliths. The final ZrB<sub>2</sub>-based paste exhibited an elastic shear modulus of ~10<sup>4</sup> Pa, …
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Advanced Synthesis of Ultra-High Temperature Ceramics (UHTCs) and High Temperature Electron Emitting Materials
… First, the ultra-high temperature ceramic (UHTC) zirconium diboride or ZrB2 was sintered by ultra-fast high temperature sintering (UHS). The UHS process was optimized and the sintering parameters for ZrB2 and other UHTCs were studied. ZrB2 is an ultra-high temperature ceramic (UHTC) with a very …
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Oxidation of ZrB₂-30 vol% SiC at 1500⁰C with emphasis on reactions involving SiC
"The focus of the Ph.D. dissertation is on understanding the chemical processes responsible for oxidation of ZrB₂-SiC ceramics at 1500⁰C"--Abstract, page iv.
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Fabricating Complex-Shaped Components by Room-Temperature Injection Molding of Aqueous Ceramic Suspension Gels
… and processing prior to tailoring the process to zirconium diboride (ZrB<sub>2</sub>), an ultra-high temperature ceramic (UHTC) system.</p> <p>CeraSGels were highly loaded (>50 vol.%) with alumina powder and had a minimal amount (≤5 vol.%) of water-soluble polyvinylpyrrolidone (PVP). Rheological …
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Improving the oxidation resistance of diboride-based ceramics
<p>"Oxidation behavior has restricted the development of ZrB₂-based ceramics for aerospace and hypersonic flight vehicles applications. The research presented in this dissertation focuses on the effect of transition metal (TM) additives on oxidation behavior of ZrB₂ ceramics. In the first stage of …