Dissertations / Theses on the topic 'Ceramic materials - Thermal properties'
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Simmons, Jed. "OPTICAL AND PHYSICAL PROPERTIES OF CERAMIC CRYSTAL LASER MATERIALS." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4123.
Full textPh.D.
Department of Physics
Sciences
Physics PhD
Namjoshi, Shanatanu Ashok. "Reaction synthesis of dynamically-densified Ti-based intermetallic and ceramic forming powders." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19572.
Full textZahedi, Maryam. "Meshfree Method for Prediction of Thermal Properties of Porous Ceramic Materials." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/954.
Full textYang, Fan. "Electrical and thermal properties of yttria-stabilised zirconia (YSZ)- based ceramic materials." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/electrical-and-thermal-properties-of-yttriastabilised-zirconia-ysz-based-ceramic-materials(82568afe-ffcb-4a38-9166-e5de83337763).html.
Full textFurlong, Scott Davis. "Reduction of radiated thermal conductivity in thin-wall hollow ceramic spheres using scattering phases." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/9341.
Full textGraham, Samuel Jr. "Effective thermal condutivity of damaged composites." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16935.
Full textAppiah, Kwadwo Ampofo. "Microstructural and microanalytical characterization of laminated (C-SiC) matrix composites fabricated by forced-flow thermal-gradient chemical vapor infiltration (FCVI)." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/14910.
Full textCarlson, Glenn Ernest. "Thermal conductivity and infrared reflectance of hollow glass spheres." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/9474.
Full textJadhav, Amol D. "Processing, characterization, and properties of some novel thermal barrier coatings." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1183851697.
Full textGonzalez, Ralph P. "Hollow sphere radiant thermal conductivity reduction using infrared pore opacification." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/20495.
Full textZhao, Yilin [Verfasser]. "Thermo-mechanical properties of glass-ceramic solid oxide fuel cell sealant materials / Yilin Zhao." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1046975137/34.
Full textTeague, Michael Phillip. "Modeling and measurement of thermal residual stresses and isotope effects on thermo physical properties of ZrB₂-SiC ceramics." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/MichaelTeague_09007dcc8056387c.pdf.
Full textVita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed August 27, 2008) Includes bibliographical references.
Darvish, Shadi. "Thermodynamic Investigation of La0.8Sr0.2MnO3±δ Cathode, including the Prediction of Defect Chemistry, Electrical Conductivity and Thermo-Mechanical Properties." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3653.
Full textApreutesei, Mihai. "Temperature impact on thermal evolution of advanced PVD ceramic and metallic glass thin films : Physico-chemical and microstructural analysis." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0009/document.
Full textIn the recent years the industrial requirements to develop new functional materials able to overcome the severe conditions during machining operation are continuously increasing. Researchers then must find novel solutions to respond to their severe industrial requirements. To coat the tool surface with advanced coatings is the most efficient solution. New nanostructured materials may nowadays exhibit unique mechanical, physical and chemical properties ensuring notable degradation resistance where the surface protection of materials against corrosion, wear, friction or oxidation is a key issue, particularly when operating in hostile environments. Within the scope of this Ph.D. thesis the influence of the temperature on the structural stability of two different PVD ceramic and metallic glass thin films is proposed. The main goal consists in the development of two distinct classes of thin films, with a wide range of properties. In order to prepare these films, the project will be focused on the study on the influence of PVD deposition conditions in the particular film’s growth characteristics: chemical composition, structure, morphology and the subsequent changes in the main properties of the thin films, namely oxidation and crystallization resistance, especially. For that purpose we adopted the multiscale approach. The first part is related to the ceramic CrN-based coatings to give new functionalities and improve the tools’ surface with the primary aim to increase their lifetime. Secondly, new protective materials able to better protect the exposed surfaces against high temperature oxidation have been proposed, namely CrAlN and CrAlYN coatings as will be evidenced in this manuscript. The second part of the manuscript is dedicated to the innovative Zr-Cu thin films metallic glasses prepared by a PVD magnetron co-sputtering method with the objective to investigate the amorphization ability and their structural properties. Their excellent properties at room temperature have recently attracted attention as a new class of materials with great potential for engineering applications due to unique mechanical and physico-chemical characteristics (high elastic strain limit, corrosion resistance…). Finally, an important approach during the course of this thesis was the real time observation of the structure and surface modifications during heating by means of in situ methods. The thin films proposed during the course of the work could be straightforward used as surface engineering solutions to protect and extend the lifetime of the materials and components
SANTOS, WILSON N. dos. "Contribuicao ao estudo da condutividade termica do material ceramico concreto refratario utilizando a tecnica de fio quente com ajustes por regressao nao linear." reponame:Repositório Institucional do IPEN, 1988. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9901.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Šafaříková, Hana. "Vliv obsahu kalcitu v cihlářských zeminách na vlastnosti vypáleného střepu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225878.
Full textOliveira, Paulo Willyam SimÃo de. "Study of dielectric properties in the microwave MgTiO3 Arrays (MTO) - CaCu3Ti4O12 (CCTO) and BiNbO4 - CuO and its thermal stability for use in communication systems." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15904.
Full textWith the recent advances in telecommunications industry in antenna area itâs increasingly required the development of ceramic materials which have high values of permittivity dielectric, low dielectric loss and a good thermal stability. Dielectric ceramics of CaCu3Ti4O12 are candidates as high values of permittivity dielectric materials and have been studied extensively. Nowadays ceramics offer materials several significant advantages in relation to others since present low production cost for electronic devices that operate of radio and microwave frequency, as well as being low weight materials, stable with temperature and extremely amenable to miniaturization. Sample preparation for structural analysis and dielectric, had the addition of CaCu3Ti4O12 to the phase MgTiO3 calcined in ratios of 4.0; 6.0; 8.0; 10.0 and 12.0 % by mass. The X-ray diffraction was important for the structural characterization of the obtained composite. The morphology of the samples was observed by Scanning Electron Microscopy (SEM). The dielectric characterization of radio frequency spectroscopy of impedance was performed which occurred two conductivity mechanisms for a sample. Models of dielectric relaxation approach the Cole-Cole and Havriliak-Negami type model. The experiments indicated that it is possible to obtain ceramic composites with good values of dielectric permittivity and low dielectric losses, resulting in scalebility and efficiency for devices designed to operate in those frequencies. Numerical simulation was performed with samples verifying good agreement with the experimental data. They studied the BiNbO4 phase doped with copper oxide and its possible applications in RF and Microwave. Addition of CaCu3Ti4O12 with MgTiO3 matrix contributed to the reduction of temperature coefficient of resonant frequency -39.25 ppm/ÂC to 9.62 ppm/ÂC, increased dielectric permittivity and dielectric loss. This thesis also presents a proposal for samples act as dielectric resonator antennas in the frequency range of 5.4 GHz to 6.1 GHz (C-band).The composites evaluated in this work has behaved properly as materials for use in microwave
Com os recentes avanÃos da indÃstria de telecomunicaÃÃes na Ãrea de antenas se faz cada vez mais necessÃrio o desenvolvimento de materiais cerÃmicos que apresentem altos valores de permissividade dielÃtrica, baixa perda dielÃtrica e uma boa estabilidade tÃrmica. CerÃmicas dielÃtricas CaCu3Ti4O12 sÃo candidatas como materiais de elevado valor de permissividade dielÃtrica e tÃm sido estudadas amplamente. Hoje as cerÃmicas oferecem vÃrias vantagens por apresentarem baixo custo de produÃÃo para dispositivos eletrÃnicos que operam em radiofrequÃncia e micro-ondas, alÃm de serem materiais de peso pequeno, estÃveis com a temperatura e extremamente passÃveis de miniaturizaÃÃo. A preparaÃÃo das amostras para anÃlise estrutural e dielÃtrica, teve a adiÃÃo de CaCu3Ti4O12 à fase MgTiO3 calcinada, em proporÃÃes de 4,0; 6,0; 8,0; 10,0 e 12,0 % em massa. A difraÃÃo de raios-X foi importante na caracterizaÃÃo estrutural dos compÃsitos obtidos. A morfologia das amostras foi estudada pela microscopia eletrÃnica de varredura (MEV). A caracterizaÃÃo dielÃtrica em rÃdio frequÃncia foi realizada por Espectroscopia de ImpedÃncia na qual se verificaram dois mecanismos de condutividade para uma das amostras analisadas. Os modelos de relaxaÃÃo dielÃtrica se aproximam do modelo do tipo Cole-Cole e Havriliak-Negami. Os experimentos realizados indicaram que à possÃvel obter compÃsitos cerÃmicos com bons valores de permissividade dielÃtrica e baixas perdas dielÃtricas, resultando em compactaÃÃo e eficiÃncia para dispositivos a serem projetados. SimulaÃÃo numÃrica foi realizada com as amostras verificando-se boa concordÃncia com os dados experimentais. Foram estudadas a fase BiNbO4 dopada com CuO e suas possÃveis aplicaÃÃes em radiofrequÃncia e micro-ondas. A AdiÃÃo de CaCu3Ti4O12 à matriz MgTiO3 contribuiu para a reduÃÃo do coeficiente de temperatura da frequÃncia de ressonÃncia de -39,25 ppm/ÂC para 9,62 ppm/ÂC, com o aumento da permissividade dielÃtrica e da perda dielÃtrica. Este trabalho de tese tambÃm apresenta uma proposta para as amostras funcionarem como antenas ressonadoras dielÃtricas na faixa de frequÃncias de 5,4 GHz a 6,1 GHz (banda C). Os compÃsitos avaliados nesse trabalho comportaram-se adequadamente como materiais para uso em micro-ondas.
SILVA, MAVIAEL J. da. "Desenvolvimento de selantes vitrocerâmicos para uso em SOFC pertencentes ao sistema BAS (BaO-Alsub(2)0sub(3)-SiOsub(2)) modificados com Bsub(2)Osub(3)." reponame:Repositório Institucional do IPEN, 2014. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23655.
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Ben, Kaabar Aymen. "Durabilité des assemblages céramique-métal employés en électronique de puissance." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0064/document.
Full textThe power electronics components (and still will have!) have a great influence on the energy and transport sectors. These parts are made of ceramic-copper assemblies for which the mechanical strength must be controlled to ensure durability about 30 years under the thermal cycles increasingly larger. A failure mechanisms analysis in DBC (Direct Copper Bonding) assemblies used in power electronics is studied (the delamination along the interface copper - ceramic and/or the brittle ceramic fracture). To identify the elastoplastic behavior of copper, we showed that it’s necessary to use a copper plate having undergone the heat hole treatments related to the assembly process. The ceramic gragile elastic behavior is descrobed within the Weibull statictics framework. Consequently, a copper-ceramic delamination characterization under four points bending made it possible to identify a cohesive model for the interface. The cohesive calibration parameters is carried out by using the data in two scales: i) strentgh-displacement macroscopic ii) local cracking optical follow-up with imposed displacement. The mechanical integrity of DBC assemblies of different thickness of copper and ceramic has been studied. We showed that the configurations with a ratio close to the unit are most dangerous by generating a delamination, which continues under thermal cycling. This risk of delamination can be notably reduced by structuring the copper circumference surface with cylindrical holes distributed periodically. Thus, a finite elements model allowing us to evaluate the most promising assemblies in term of durability, was estabilshed. In the absence of geometrical defects, the copper layer must remains, even in the delamination case whose face induces a concentration stress
RAMBO, CARLOS R. "Sintese e caracterizacao de ceramicas biomorficas." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10973.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
SILVA, PAULO S. M. da. "Projeto, construção e testes de um sistema de medidas elétricas e estudo de compósitos de zircônia-ítria e nitreto de titânio." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/25318.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Oskar, Bera. "Dobijanje i karakterizacija suspenzija nanočestica i njihovih kompozita." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2012. https://www.cris.uns.ac.rs/record.jsf?recordId=85618&source=NDLTD&language=en.
Full textIn this work, polymeric and ceramic nanostructured materials were prepared using different methods, in order to investigate the influence of nanofiller content and its type (carbon black, fullerene, silica, alumina and titania) on the structure, rheological and thermal behavior of composites, based on styrene, methylmethacrylate and acrylamide. The effect of particles content (1, 3 and 5 wt. %) on the kinetics of styrene radical polymerization and on the glass transition temperature of polystyrene/silica composites was investigated. A series of polymethylmethacrylate nanocomposites containing 1 vol. % of silica, alumina or titania particles (differing in dimensions and surface properties) was obtained. On the basis of isothermal differential scanning calorimetry (DSC), the kinetic model for describing two reactions during vinyl monomer polymerization (first order and autoacceleration) was developed, and the thickness of interfacial layer formed on nanoparticle surface was determined, in order to investigate its influence on the glass transition temperature of polymethylmethacrylate hybrid materials. The structure and the morphology of polystyrene/silica nanocomposites prepared by solvent evaporation were investigated using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The influence of hydrophobic silica content (2, 5, 10, 15 and 30 wt. %) on polystyrene thermal stability was studied by simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC). The effect of fullerene C60 and submicron carbon black particle size on rheological properties of polystyrene composites prepared by the rapid coprecipitation was determined. Following the rheology of hybrid melts, the influence of filler size, molecular weight and polydispersity of polymer matrix on the viscosity of polystyrene composites was studied. On the basis of in-situ rheology analysis of polymerization process during the gelation of alumina nanoparticles suspension in aqueous solution of methacrylamide and N,N’- methylene bisacrylamide monomers, the strong catalytic activity of alumina surface on the free radicals formation was determined. In order to find the correlation between desired properties of ceramic products and their preparation procedure route, the influence of polymerization conditions on the green body structure and sintered body density was studied in details.
Yun, Jeong Woo. "Permeability analysis for thermal binder removal from green ceramic bodies." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4806.
Full textThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 16, 2007) Vita. Includes bibliographical references.
Miller, Jean P. "Long-term thermal/chemical degradation of ceramic candle filter materials." Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/41704.
Full textMaster of Science
Yeomans, J. A. "Ceramic tool materials : structure and properties relevant to wear." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233360.
Full textMisra, Rajnish. "Controlled drying to enhance properties of technical ceramic materials." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366120.
Full textRickles, Stacey A. "Microstructural and compressive properties of a metal/ceramic syntactic foam." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/19677.
Full textDunyak, Thomas John. "Properties and performance of a ceramic composite component." Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134634/.
Full textSachanandani, Rajiv M. Lombardo Stephen. "Failure analysis of green ceramic bodies during thermal debinding." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6491.
Full textHellman, Olle. "Thermal properties of materials from first principles." Doctoral thesis, Linköpings universitet, Teoretisk Fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78755.
Full textZbären, Christoph Oliver. "The effect of thermal cycling on metal-ceramic bond strength /." [S.l.] : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000288150.
Full textTu, Jie. "Thermal expansion of chemically modified mullite." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43063.
Full textMaster of Science
Grande, Dodd Harrison. "Testing and properties of high temperature glass-ceramic matrix composites." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14952.
Full textMICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 109-118.
by Dodd Harrison Grande.
Ph.D.
Arrighi, Aloïs. "Thermal and thermoelectric properties of two-dimensional materials." Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2020. http://hdl.handle.net/10803/670380.
Full textLa gestión térmica es un problema crítico en el diseño de dispositivos nanoelectrónicos. Las soluciones de enfriamiento avanzadas y la recolección eficiente de energía son clave para mantener la tendencia de productos electrónicos cada vez más pequeños y rápidos. Esta tesis se centra en la gestión térmica y el uso de calor disipado en materiales emergentes para la electrónica. En particular, los materiales bidimensionales (2DM) y las heteroestructuras basadas en ellos son candidatos muy interesantes para el futuro de la electrónica y se están investigando intensamente. La tesis trata dos temas principales: (i) el transporte térmico de 2DMs suspendidos, incluido el grafeno CVD, dicalcogenuros de metales de transición (TMDC) y heteroestructuras de TMDC con nitruro de boro hexagonal (hBN); y (ii) las propiedades térmicas y de termoelectricidad de películas delgadas de (Bi1-xSbx)2Te3(BST). Estos materiales están siendo considerados para interconexiones y transistores hasta THz (grafeno), electrónica digital (TMDCs) y aislamiento eléctrico (hBN) y son bien conocidos como generadores termoeléctricos, como también lo son materiales recientemente identificados como aislantes topológicos (BST). En primer lugar, el objetivo fue medir la conductividad térmica de 2DMs utilizando el método de espectroscopia Raman de dos láser, recientemente desarrollado. El desafío fue el uso de membranas relativamente pequeñas obtenidas y su alta conductividad térmica. Demostramos que la conductividad térmica del grafeno CVD es de aproximadamente 300 W/(m·K). Aunque menor que en el grafeno exfoliado, esto podría deberse a los bordes de grano y al desorden en grafeno CVD. Demostramos también que las conductividades térmicas de MoS2 y MoSe2 exfoliados (dos TMDC) son 12 a 24 W/(m·K) y 60 W/(m·K), respectivamente. Y que para membranas delgadas (pocas monocapas) la conductividad incrementa con su grosor. Agregando una membrana de hBN exfoliada sobre una muestra de MoS2 previamente caracterizada nos permitió demostrar un notable aumento de la conductividad térmica en la heteroestructura de hBN/MoS2, cuando se introduce calor en MoS2. Esta presenta una conductividad térmica de 185 W/(m·K), casi un orden de magnitud mayor que para MoS2. En segundo lugar, se estudiaron películas delgadas de BST crecidas mediante epitaxia de haz molecular con el objetivo de correlacionar sus propiedades termoeléctricas con su nivel de Fermi, que sintonizaría el peso relativo del transporte de volumen y de los estados topológicos de superficie (TSS). Primero demostramos que es posible diseñar la estructura de la banda y ajustar el nivel de Fermi desde la valencia hasta la banda de conducción simplemente controlando la concentración de Sb. Para ello se utilizó espectroscopia de fotoemisión con resolución angular en combinación con conductividad eléctrica y mediciones de Hall en películas relativamente delgadas (10 nm). También se identificó la concentración de Sb a la que los TSSs dominan el transporte y se llevaron a cabo experimentos termoeléctricos en las mismas películas. No se encontró una correlación clara entre la energía termoeléctrica y la naturaleza de los portadores de carga cuando los TSSs eran dominantes, indicando que el transporte de los TSSs tiene una influencia limitada en las propiedades termoeléctricas de este material y que para observar los efectos de superficie se necesitarían películas más delgadas. Finalmente, una caracterización de las películas delgadas de BST usando espectroscopia Raman demostró variaciones específicas en el comportamiento asociado a la concentración de Sb. En particular, el aumento de la potencia del láser dio lugar a la aparición de picos Raman no activos de origen indeterminado. Estos picos pueden indicar la ruptura de simetrías estructurales, modos de fonón de superficie u otros efectos tales como resonancias plasmónicas que son de alto interés, una respuesta que debería motivar investigaciones adicionales.
Thermal management is becoming a critical issue in the packaging and design of nanoelectronics. Advanced cooling solutions and efficient energy harvesting are key aspects to help keep the trend for ever smaller and faster electronics. This thesis is focused on thermal management and the use of heat waste in emerging materials for electronics. In particular, two-dimensional materials (2DM), and related heterostructures, are amongst the most intriguing prospects for future electronics and are being intensively investigated. Here, two main subjects were explored. First, the thermal transport of suspended 2DMs, including CVD graphene, transition metal dichalcogenides (TMDCs) and heterostructures of TMDCs with hexagonal boron nitride (hBN) and, second, the thermal properties and thermoelectricity of (Bi1-xSbx)2Te3 (BST) thin films. These materials are being considered for interconnects and THz transistors (graphene), digital electronics (TMDCs) and electrical insulation (hBN) and are well known as thermoelectric generators, as are also materials that have recently been identified as topological insulators (BST). In the first part, the objective was to demonstrate the measurement of the thermal conductivity of 2DMs using the recently developed two-laser Raman spectroscopy method. Its implementation was rendered difficult by the relatively small exfoliated flakes of the materials investigated and their high thermal conductivity. The thermal conductivity of CVD graphene was found to be about 300 W/(m·K). Although smaller than exfoliated graphene, it is argued that this could be due to grain boundaries and disorder. Exfoliated MoS2 and MoSe2 (two well-known TMDCs) presented thermal conductivities of 12 to 24 W/(m·K) and 60 W/(m·K). Measurements on different membranes of MoS2 further showed that the conductivity increases with the thickness in thin membranes (few monolayers). Furthermore, stacking an exfoliated hBN membrane on top of a previously characterized MoS2 sample allowed us to demonstrate a notorious increase of the thermal conductivity in the hBN/MoS2 heterostructure, when heat is introduced on MoS2. Indeed, when compared with MoS2 alone the thermal conductivity is found to be almost one order of magnitude larger, 185 W/(m·K). For the second part, BST thin films were grown by molecular beam epitaxy. The main objective was to investigate the correlation of the thermoelectric properties of these materials with the Fermi level, which would tune the relative weight of bulk and topological surface state (TSS) transport. It was first demonstrated that controlling the concentration of Sb we could engineer the band structure and tune the Fermi level from the valence to the conduction band. Such demonstration was achieved by using angle-resolved photoemission spectroscopy in combination with conductivity and Hall measurements in relatively thin (10 nm) films. The Sb concentration at which TSS dominated the transport was also identified. Thermoelectric experiments on the same films were then carried out but no clear correlation between the thermopower and the carrier nature was found when the TSSs were dominant. These results indicate that TSS transport has limited influence on the thermoelectric properties. Further studies should be carried our using even thinner films. Finally, a side characterization of the BST thin films using Raman spectroscopy demonstrated specific variations in the behaviour associated to Sb concentration. An increase of the laser power showed the emergence of non-active Raman peaks of undetermined origin. However, they can indicate the presence of broken structural symmetries, surface phonon modes or other effects such as plasmonic resonances. This interesting response is worthy of for further investigation.
Universitat Autònoma de Barelona. Programa de Doctorat en Física
Modica, S. P. "The thermal properties of homogeneous and composite materials." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/35579.
Full textEnglish, Jennifer M. "Wireless micromachined ceramic pressure sensors for high termperature environments." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/15790.
Full textBhatt, Hemanshu D. "Effect of interfacial thermal conductance and fiber orientation on the thermal diffusivity/conductivity of unidirectional fiber-reinforced ceramic matrix composites." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-07282008-135034/.
Full textLind, Cora. "Negative thermal expansion materials related to cubic zirconium tungstate." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/30861.
Full textPorwal, Harshit. "Processing and properties of graphene reinforced glass/ceramic composites." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9107.
Full textPapageorge, Marc Vasilios. "Characterization of metal/ceramic interfaces on aluminum nitride." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/9352.
Full textGilbank, Alexander. "Ceramic nanostructured catalysts." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648952.
Full textLiao, Hao-Hsiang. "Thermal and thermoelectric properties of nanostructured materials and interfaces." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/19198.
Full textPh. D.
Memon, Muhammad Omar. "Carbon Nanostructures As Thermal Interface Materials: Processing And Properties." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1304020760.
Full textMcClorey, Catherine. "Compositional and mechanical properties of polymer/ceramic composite materials for medical applications." Thesis, University of Ulster, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369954.
Full textSpencer, Joel Quintus. "The development of luminescence methods to measure thermal exposure in lithic and ceramic materials." Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/3557/.
Full textIwagoshi, Joel A. "Thermal Vapor Deposition and Characterization of Polymer-Ceramic Nanoparticle Thin Films and Capacitors." Thesis, Northern Arizona University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1537781.
Full textResearch on alternative energies has become an area of increased interest due to economic and environmental concerns. Green energy sources, such as ocean, wind, and solar power, are subject to predictable and unpredictable generation intermittencies which cause instability in the electrical grid. This problem could be solved through the use of short term energy storage devices.
Capacitors made from composite polymer:nanoparticle thin films have been shown to be an economically viable option. Through thermal vapor deposition, we fabricated dielectric thin films composed of the polymer polyvinylidine fluoride (PVDF) and the ceramic nanoparticle titanium dioxide (TiO2). Fully understanding the deposition process required an investigation of electrode and dielectric film deposition. Film composition can be controlled by the mass ratio of PVDF:TiO2 prior to deposition. An analysis of the relationship between the ratio of PVDF:TiO2 before and after deposition will improve our understanding of this novel deposition method.
X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy were used to analyze film atomic concentrations. The results indicate a broad distribution of deposited TiO2 concentrations with the highest deposited amount at an initial mass concentration of 17% TiO2.
The nanoparticle dispersion throughout the film is analyzed through atomic force microscopy and energy dispersive x-ray spectroscopy. Images from these two techniques confirm uniform TiO2 dispersion with cluster size less than 300 nm. These results, combined with spectroscopic analysis, verify control over the deposition process.
Capacitors were fabricated using gold parallel plates with PVDF:TiO 2 dielectrics. These capacitors were analyzed using the atomic force microscope and a capacohmeter. Atomic force microscope images confirm that our gold films are acceptably smooth. Preliminary capacohmeter measurements indicate capacitance values of 6 nF and break down voltages of 2.4 V.
Our research on the deposition process will contribute to the understanding of PVDF/TiO2 composite thin films. These results will lead to further investigation of PVDF/TiO2 high density energy storage capacitors. These capacitors can potentially increase the efficiency of alternative energy sources already in use.
Van, Aken Stephen Mark. "Thermal expansion and thermal conductivity of (Ca1-x,Mgx)Zr₄(PO₄)₆ where x = 0.0-0.4." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42159.
Full textMaster of Science
Robotti, Marco. "Functional surfaces obtained by thermal spray techniques." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/400558.
Full textEl tema principal de esta tesis doctoral es la fabricación de recubrimientos multifuncionales de dióxido de titanio mediante técnica de proyección fría (CGS) y proyección por plasma atmosférico (APS). Cada producto en forma de recubrimiento funcional encontró su sector de aplicación: i) fotocatálisis en fase gaseosa, ii) fotoelectrocatálisis en fase liquida, iii) electrodos para baterías y iv) sensores de gas. El primer objetivo de esta tesis doctoral consistió en el desarrollo de recubrimientos nano-estructurados de TiO2 anatasa mediante técnica de proyección fría CGS. La grande superficie específica de este material nanométrico es útil para su aplicación en el campo de la fotocatálisis heterogénea. Fueron preparadas unas mezclas mecánicas entre materiales nano-cerámicos y poliméricos con adecuada fluidez para el sistema de alimentación CGS. Las muestras obtenidas degradaron los gases NOx en breve tiempo y con elevadas eficiencias tanto con luz UV como con luz visible (FEAM Grupo de fotocatálisis y Espectroscòpia Aplicada al Medioambiente, Universidad de Las Palmas de Gran Canaria). El segundo propósito de esta investigación consistió en proyectar tres diferentes tipos de TiO2 (100% anatasa, 100% rutilo y sub-óxidos) por tecnología APS y evaluar las actividades fotocatalíticas en fase liquida. El rendimiento de los recubrimientos aplicados como fotoánodos fue analizado con el proceso SPEC Solar Photoelectrocatalysis. El estudio llevó a la conclusión que los recubrimientos con mayor parte de fases cristalinas (anatasa y rutilo), mayor rugosidad 3D de superficie y adecuado espesor presentan mejor desempeño fotoelectrocatalítico. (Grupo LEMMA Laboratori d’Electroquímica de Materials i del Medi Ambient, Universitat de Barcelona). La tercera finalidad de este trabajo fue depositar óxidos metálicos por APS para ser aplicados como electrodos en baterías reales. El hidrógeno contenido en el flujo de plasma de APS es capaz de reducir el óxido metálico TiO2 de partida, crear vacantes de oxígeno y compuestos no estequiométricos como sub-óxidos de titanio (TiO2-x) o fases de Magnéli (TinO2n-1). Esta falta de oxígeno aumenta la conductividad del material que además resiste bien contra la corrosión. Fueron fabricados recubrimientos sobre acero inoxidable, láminas de aluminio, material compuesto de polímero reforzado con carbono y espuma de níquel. Cuatro placas de TiO2-x sobre sustratos de aluminio se aplicaron como electrodos en una batería de escala de laboratorio. Se realizaron las curvas de voltametría cíclica y los ciclos de carga/descarga de la batería de plomo y los resultados fueron excelentes (Facultad de Ingeniería y Medio Ambiente, Universidad de Southampton). El último objetivo de este doctorado consistió en el desarrollo de nuevos sensores de gas funcionales a través de la tecnología de APS. Se estableció hacer crecer la capa sensorica sobre un sustrato cerámico delgado para poder aumentar la temperatura de trabajo. Las condiciones de proyección fueron seleccionadas para alcanzar una buena deposición, no dañar el sustrato y aumentar la cantidad de vacantes de oxígeno. La detección fue analizada a diferentes temperaturas de trabajos y los rendimientos fueron satisfactorios (Grupo MIND Micronanotecnologies I Nanoscòpies per Dispositius electrònics i fotònics, Facultad de Física, Universitat de Barcelona).
Jantunen, H. (Heli). "A novel Low Temperature Co-firing Ceramic (LTCC) material for telecommunication devices." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:951426553X.
Full textHudiono, Yeny C. "Thermal transport properties of nanoporous zeolite thin films." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24748.
Full textCommittee Chair: Prof. Sankar Nair; Committee Co-Chair: Prof. Samuel Graham; Committee Member: Prof. Amyn S. Teja; Committee Member: Prof. Mo Li; Committee Member: Prof. Peter Ludovice.