Academic literature on the topic 'Yttrium oxide based coating'
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Journal articles on the topic "Yttrium oxide based coating"
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Park, Seung Hyun, Kyung Eon Kim, and Sang Jeen Hong. "Surface Analysis of Chamber Coating Materials Exposed to CF4/O2 Plasma." Coatings 11, no. 1 (2021): 105. http://dx.doi.org/10.3390/coatings11010105.
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Coating the inner surfaces of high-powered plasma processing equipment has become crucial for reducing maintenance costs, process drift, and contaminants. The conventionally preferred alumina (Al2O3) coating has been replaced with yttria (Y2O3) due to the long-standing endurance achieved by fluorine-based etching; however, the continuous increase in radio frequency (RF) power necessitates the use of alternative coating materials to reduce process shift in a series of high-powered semiconductor manufacturing environments. In this study, we investigated the fluorine-based etching resistance of atmospheric pressure-sprayed alumina, yttria, yttrium aluminum garnet (YAG), and yttrium oxyfluoride (YOF). The prepared ceramic-coated samples were directly exposed to silicon oxide etching, and the surfaces of the plasma-exposed samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. We found that an ideal coating material must demonstrate high plasma-induced structure distortion by the fluorine atom from the radical. For endurance to fluorine-based plasma exposure, the bonding structure with fluoride was shown to be more effective than oxide-based ceramics. Thus, fluoride-based ceramic materials can be promising candidates for chamber coating materials.
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VALLEJO, N. DIAZ, O. SANCHEZ, J. C. CAICEDO, W. APERADOR, and G. ZAMBRANO. "HOT CORROSION OF YTTRIUM STABILIZED ZIRCONIA COATINGS DEPOSITED BY AIR PLASMA SPRAY ON A NICKEL-BASED SUPERALLOY." Surface Review and Letters 24, no. 06 (2016): 1750084. http://dx.doi.org/10.1142/s0218625x17500846.
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In this research, the electrochemical impedance spectroscopy (EIS) and Tafel analysis were utilized to study the hot corrosion performance at 700[Formula: see text]C of air plasma-sprayed (APS) yttria-stabilized zirconia (YSZ) coatings with a NiCrAlY bond coat grown by high velocity oxygen fuel spraying (HVOF), deposited on an INCONEL 625 substrate, in contact with corrosive solids salts as vanadium pentoxide V2O5 and sodium sulfate Na2SO4. The EIS data were interpreted based on proposed equivalent electrical circuits using a suitable fitting procedure performed with Echem AnalystTM Software. Phase transformations and microstructural development were examined using X-ray diffraction (XRD), with Rietveld refinement for quantitative phase analysis, scanning electron microscopy (SEM) was used to determinate the coating morphology and corrosion products. The XRD analysis indicated that the reaction between sodium vanadate (NaVO[Formula: see text] and yttrium oxide (Y2O[Formula: see text] produces yttrium vanadate (YVO[Formula: see text] and leads to the transformation from tetragonal to monoclinic zirconia phase.
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Vilar, Rui, and Edson Costa Santos. "Structure of NiCrAlY Coatings Deposited on Oriented Single Crystal Superalloy Substrates by Laser Cladding." Advanced Materials Research 278 (July 2011): 503–8. http://dx.doi.org/10.4028/www.scientific.net/amr.278.503.
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In the present work single and multiple layer NiCrAlY coatings were produced by laser cladding on (100) single-crystalline substrates of SRR99 Ni-based superalloy. Detailed structural characterisation and texture analysis by optical microscopy, scanning electron microscopy, X-ray diffraction and Rutherford backscattering showed that the NiCrAlY coatings consisted essentially of gamma phase with yttrium oxide (Y2O3) and a small proportion of yttrium–aluminium garnet (Al5Y3O12) precipitated in the interdendritic regions. The coatings presented a columnar dendritic structure grown by epitaxial solidification on the substrate and inherited the single-crystalline nature and the orientation of the substrate. The coating material also showed a mosaicity and a defect density similar to those of the substrate. It can be expected that the protective effect of these coatings against oxidation is greatly enhanced compared with polycrystalline coatings because high diffusivity paths, such as grain boundaries, are eliminated in single-crystalline coatings, thus reducing mass transport through the coating.
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Li, Pei Huan, Yong Zhang, and Xuan Hui Qu. "Effect of Y2O3 Coating on the Interface and Mechanical Properties of SiC Fiber Reinforced GH4738 Composites." Materials Science Forum 898 (June 2017): 604–8. http://dx.doi.org/10.4028/www.scientific.net/msf.898.604.
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To prevent the strong interfacial reactions in SiC fiber reinforced nickel-based superalloys matrix composites, yttrium oxide (Y2O3) was used as the barrier coating by reaction magnetron sputtering method. Compared with the composites without coating, after the high temperature hot isostatic pressing (HIP), Y2O3 coating effectively protected the SiC fibers from the interfacial reactions, and no element diffusion can be observed between the fibers and the matrix. The elevated temperature tensile tests were performed on both SiC/GH4738 and SiC/Y2O3/GH4738 composite. The results indicated that the strength of the composites with Y2O3 coating can increase about 35% in comparison with the composites without coating.
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Vaßen, Robert, Emine Bakan, Caren Gatzen, Seongwong Kim, Daniel Emil Mack, and Olivier Guillon. "Environmental Barrier Coatings Made by Different Thermal Spray Technologies." Coatings 9, no. 12 (2019): 784. http://dx.doi.org/10.3390/coatings9120784.
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Environmental barrier coatings (EBCs) are essential to protect ceramic matrix composites against water vapor recession in typical gas turbine environments. Both oxide and non-oxide-based ceramic matrix composites (CMCs) need such coatings as they show only a limited stability. As the thermal expansion coefficients are quite different between the two CMCs, the suitable EBC materials for both applications are different. In the paper examples of EBCs for both types of CMCs are presented. In case of EBCs for oxide-based CMCs, the limited strength of the CMC leads to damage of the surface if standard grit-blasting techniques are used. Only in the case of oxide-based CMCs different processes as laser ablation have been used to optimize the surface topography. Another result for many EBCs for oxide-based CMC is the possibility to deposit them by standard atmospheric plasma spraying (APS) as crystalline coatings. Hence, in case of these coatings only the APS process will be described. For the EBCs for non-oxide CMCs the state-of-the-art materials are rare earth or yttrium silicates. Here the major challenge is to obtain dense and crystalline coatings. While for the Y2SiO5 a promising microstructure could be obtained by a heat-treatment of an APS coating, this was not the case for Yb2Si2O7. Here also other thermal spray processes as high velocity oxygen fuel (HVOF), suspension plasma spraying (SPS), and very low-pressure plasma spraying (VLPPS) are used and the results described mainly with respect to crystallinity and porosity.
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Feriyanto, Dafit, Maizlinda Izwana Idris, Darwin Sebayang, Ashraf Bin Otman, and Pudji Untoro. "Microstructure Study on Fe/Cr Based Alloys Added with Yttrium Oxide (Y2O3) Prepared via Ultrasonic Technique for Solid Oxide Fuel Cell (SOFC) Application." Applied Mechanics and Materials 493 (January 2014): 651–55. http://dx.doi.org/10.4028/www.scientific.net/amm.493.651.
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Solid oxide fuel cells (SOFC) are the current research having several potential to obtain high efficiency, high energy–density power generation which operated at relatively higher temperature. Yttrium oxide (Y2O3)contributions at high temperature are accelerating to the development oxide layer of FeCr alloy. The aim of this research is to investigate the microstructure of Fe/Cr added with Y2O3acting as a reactive element. The purpose is to improve macrostructure of Fe/Cr powders which can be applied at steel industry. In this study the mixing process of Fe/Cr and Y2O3powder was conducted via ultrasonic treatment at a frequency of 22 kHz, and at two different holding time of 2.5 h and 3.5 h. The particle size of chromium (Cr) can be reduced by ultrasonic treatment at from 60µm to 30µm through threshing the cluster of Cr particle. It shows that the ultrasonic vibration effectively removes oxides and other contaminates on a surface coating. Therefore, homogeneity of the parent material, segregation, and uniform distribution of second phase were increased.
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Tanaka, R., A. Fujishima, Y. Shibata, A. Manabe, and T. Miyazaki. "Cooperation of Phosphate Monomer and Silica Modification on Zirconia." Journal of Dental Research 87, no. 7 (2008): 666–70. http://dx.doi.org/10.1177/154405910808700705.
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Ceramic restorations with resin-based adhesive systems have been the focus of recent attention in clinical dentistry. Yttrium-oxide-partially-stabilized zirconia (YPSZ) ceramics have optimized physical properties and exhibit favorable fracture toughness, though their bonding properties are problematic. Although functional phosphate monomers and silica-coating by tribochemical modification were expected to improve the bonding properties between YPSZ ceramics and resin-based adhesives, these two methods remain controversial. This study evaluated the efficiency of silica-coating by tribochemical modification of YPSZ ceramics. The application of phosphate monomer and a silane coupling agent on silica-coated YPSZ was also investigated. The silica-coating of YPSZ ceramics by tribochemical modification was not efficient, given the higher mechanical toughness of the densely sintered ceramics. Stable shear bond strength was achieved on silica-coated YPSZ ceramics with the cooperative interaction of phosphate monomer and silane coupling.
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Ma, Ze, Jie Han, Shuo Yao, Sheng Wang, and Lian-Mao Peng. "Improving the Performance and Uniformity of Carbon-Nanotube-Network-Based Photodiodes via Yttrium Oxide Coating and Decoating." ACS Applied Materials & Interfaces 11, no. 12 (2019): 11736–42. http://dx.doi.org/10.1021/acsami.8b21325.
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Molin, S., Å. H. Persson, T. L. Skafte, et al. "Effective yttrium based coating for steel interconnects of solid oxide cells: Corrosion evaluation in steam-hydrogen atmosphere." Journal of Power Sources 440 (November 2019): 226814. http://dx.doi.org/10.1016/j.jpowsour.2019.226814.
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Lee, Kang N., Nathan S. Jacobson, and Robert A. Miller. "Refractory Oxide Coatings on SiC Ceramics." MRS Bulletin 19, no. 10 (1994): 35–38. http://dx.doi.org/10.1557/s088376940004820x.
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Silicon-based ceramics are leading candidate materials for high-temperature structural applications such as heat exchangers, advanced gas turbine engines, and advanced internal combustion engines. They have excellent oxidation resistance in clean oxidizing environments due to the formation of a slow-growing silica scale (SiO2). However, durability in high-temperature environments containing molten salts, water vapor, or a reducing atmosphere can limit their applications. Molten salts react with silica scale to form liquid silicates. Oxygen readily diffuses through liquid silicates and rapidly oxidizes the substrate. High water vapor levels lead to hydrated silica species, such as Si(OH)4(g) and subsequent evaporation of protective scale. Complex combustion atmospheres containing oxidizing (CO2, H2O) and reducing (CO, H2) gases form SiO2 and then reduce it to SiO(g). In situations with extremely low partial pressures of oxidant, direct formation of SiO(g) occurs. All these reactions can potentially limit the formation of a protective silica scale and thus lead to an accelerated or a catastrophic degradation.One approach overcoming these potential environmental limitations is to apply a barrier coating which is environmentally stable in molten salts, water vapor, and/or reducing atmospheres. Refractory oxides such as mullite (3Al2O3 · 2SiO2), yttria-stabilized zirconia (ZrO2-Y2O3), or alumina (Al2O3) are promising candidate coating materials because of their excellent environmental stability in these severe conditions. Refractory oxide coatings can also serve as thermal barrier coatings because of their low thermal conductivity. Key requirements for an adherent and durable barrier coating include coefficient of thermal expansion (CTE) match and chemical compatibility with the substrate. Mullite in general meets all the requirements and thus appears most promising.
Dissertations / Theses on the topic "Yttrium oxide based coating"
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Tirala, David. "Testování a hodnocení vlastností keramických jader pro technologii vytavitelného modelu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-445169.
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Production of top quality castings for applications in energy, aerospace and medical industries by the addition of ceramic cores to investment casting presents many metallurgical and technological problems. Ceramic cores applied in investment casting are subjects to many requirements in terms of their inertness to the casted alloy and at the same time to their final removal from the casting cavity in such a way that does not damage the casting. Both of these assumptions can be achieved by applying a thin layer of inert oxide ceramic coating to the surface of a ceramic core, made out of a chemically removable – leachable oxide ceramic.
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Lin, Xin. "Yttrium disilicate as environmental barrier coating for silicon nitride-based glow plug." University of British Columbia, 2017. http://hdl.handle.net/2429/64165.
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Silicon-based ceramics undergo severe degradation at temperatures above ~1000 ℃ in the presence of water vapor, which is inevitable in combustion environments. Therefore, Environmental Barrier Coatings (EBCs) are necessary for the protection of Si₃N₄-based ceramic components in the harsh combustion environments. Rare earth silicates, which have relatively low thermal expansion coefficients, good chemical stability at high temperatures and low recession rates in the presence of water vapor, are promising candidate materials for such EBC application. This study was related to the application of Si₃N₄ as part of Hot Surface Ignition Systems (“Glow-Plugs”, GP) in High-Pressure Natural Gas Direct Injection engines, currently under development by Vancouver company Westport Fuel Systems Inc. For certain kinds of commercially available Si₃N₄-based GPs, the use of Y₂O₃ as sintering additive results in the in-service formation of yttrium silicates on their ceramic pins. Therefore, taking the chemical compatibility into consideration, yttrium disilicate coating was chosen to provide corrosion protection for such GPs. A sol-gel dip-coating route, which is simple, cost effective and industrially applicable, has been developed to apply multi-layer Y₂Si₂O₇ EBCs on the GPs. Selective processing parameters, including the sol aging conditions and the withdrawal speed of the GP substrate during dip coating procedure, were investigated in detail. The thickness and microstructures of the coatings were controlled through the adjustment of these parameters during sol preparation and dip coating processes. To simultaneously achieve sufficient thickness and avoid the formation of cracks, thin layers of Y₂Si₂O₇ coating, each with the thickness of ~1 µm, were successively applied and processed. The 6-layer crack-free coating was able to achieve an average thickness of ~5.5 µm. The microstructures of the coatings were evaluated and their performance was tested at ~1200 ℃ in high concentration water vapor atmosphere and on a natural gas burner rig. Improved corrosion resistance of such EBC-protected glow plugs was observed in these tests.<br>Applied Science, Faculty of<br>Materials Engineering, Department of<br>Graduate
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Dostál, Vladimír. "Využití oxidu yttria pro vytváření antireflexních vrstev solárních článků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218813.
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This work deals with deposition of yttrium oxide layers on silicon substrate (P – type) by using magnetron and reactive magnetron sputtering. Experiments which were made are further described. After that, work is focused on evaluation of deposited layers by using FTIR measurement technique and spectrophotometry. At the end of the work results of experiments are discussed also with the future progress.
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Mao, Fang. "Synthesis, Characterization, and Evaluation of Ag-based Electrical Contact Materials." Doctoral thesis, Uppsala universitet, Oorganisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-320235.
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Ag is a widely used electrical contact material due to its excellent electrical properties. The problems with Ag are that it is soft and has poor tribological properties (high friction and wear in Ag/Ag sliding contacts). For smart grid applications, friction and wear became increasingly important issues to be improved, due to much higher sliding frequency in the harsh operation environment. The aim of this thesis is to explore several different concepts to improve the properties of Ag electrical contacts for smart grid applications. Bulk Ag-X (X=Al, Sn In) alloys were synthesized by melting of metals. An important result was that the presence of a hcp phase in the alloys significantly reduced friction coefficients and wear rates compared to Ag. This was explained by a sliding-induced reorientation of easy-shearing planes in the hexagonal structure. The Ag-In system showed the best combination of properties for potential use in future contact applications. This thesis has also demonstrated the strength of a combinatorial approach as a high-throughput method to rapidly screen Ag-based alloy coatings. It was also used for a rapid identification of optimal deposition parameters for reactive sputtering of a complex AgFeO2 oxide with narrow synthesis window. A new and rapid process was developed to grow low frictional AgI coatings and a novel designed microstructure of nanoporous Ag filled with AgI (n-porous Ag/AgI) using a solution chemical method was also explored. The AgI coatings exhibited low friction coefficient and acceptable contact resistance. However, under very harsh conditions, their lifetime is too short. The initial tribotests showed high friction coefficient of the n-porous Ag/AgI coating, indicating an issue regarding its mechanical integrity. The use of graphene as a solid lubricant in sliding electrical contacts was investigated as well. The results show that graphene is an excellent solid lubricant in Ag-based contacts. Furthermore, the lubricating effect was found to be dependent on chemical composition of the counter surface. As an alternative lubricant, graphene oxide is cheaper and easier to produce. Preliminary tests with graphene oxide showed a similar frictional behavior as graphene suggesting a potential use of this material as lubricant in Ag contacts.
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Fang, Lei. "Exploring spin in novel materials and systems." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299611695.
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Pousaneh, Elaheh. "Synthesis and Characterization of Metal Complexes for Thin Film Formation via Spin-Coating or Chemical Vapor Deposition." 2019. https://monarch.qucosa.de/id/qucosa%3A72463.
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The present thesis describes the synthesis and characterization of magnesium, copper, and iron complexes and their application in the MOCVD (Metal-Organic Chemical Vapor Deposition) process, as well as the synthesis and characterization of yttrium and gadolinium complexes and their use as spin-coating precursors for metal oxide thin layer formation. The objective of this scientific work is the development of the family of bis(β-ketoiminato) magnesium(II) complexes and a series of heteroleptic β-ketoiminato copper(II) precursors for the formation of magnesium oxide and copper/copper oxide layers by using the MOCVD process. Modifications of the ketoiminato ligands affect the physical and chemical properties of the respective complexes. Another central theme of this work is the development of β-diketonato iron(III) complexes for the deposition of carbon-free gamma- and alpha-Fe2O3 layers via MOCVD. The thermal behavior and vapor pressure of the precursors could be influenced by the variation of the β-diketonate ligands. In addition, the synthesis and characterization of yttrium and gadolinium β-diketonates and their use as spin-coating precursors are described. Field-effect transistors were successfully fabricated by the deposition of carbon nanotubes on top of the Y2O3 films.
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Salehizadeh, Seyed Ali. "Encapsulation of iron oxide-based nanoparticles in silica for biomedical applications." Doctoral thesis, 2019. http://hdl.handle.net/10773/27748.
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Over last decades, a great attention has been devoted to iron oxide-based nanoparticles coated by dielectric organic or inorganic materials for the potential contributions in biomedical applications and microwave absorbers industry.
The present Ph.D. study focuses on the fabrication of iron-based oxide nanoparticles and coating the particles within the silica matrix in the form of a core-shell structure exhibiting interesting magnetic and electrical properties for application in the biomedical and microwave technology areas. The combined study of electrical and magnetic properties of the silica-iron oxide composites allowed us to examine the requisites for application in a new generation of the high-efficient microwave absorbents and also for the possibility of hyperthermia and drug delivery agents.
In this context, four synthesis methods: sol-gel route, laser floating zone (LFZ), auto-combustion, and Pechini method were employed to prepare the iron oxide-based/silica composites.
Several studies, namely, structural, morphological, electrical and magnetic characterizations, were performed on the prepared samples. The utilization of several experimental characterizing techniques not only provide us a comprehensive knowledge of the physical properties of these materials but also look over the future employment of the prepared composites in the biomedical application and the microwave absorbing materials.
It was prepared a series of glasses with the composition, xFe2O3-(100-x)SiO2 (x=1, 2, 10, 20 in mol%) by the sol-gel route. The effect of the heat treatment conditions and the Fe/Si ratio on the morphology, electrical and magnetic properties of the glass ceramics were investigated.
Fibers with the composition of 10Fe2O3-90SiO2 were processed by LFZ technique. Their morphology, structure, magnetic properties and redox state were studied in function of the pulling rate. An exhautive study on the Raman spectroscopy and the local magnetic microstructure of the fibers were performed to support for a deeper understanding of the magnetic properties of the fibers.
A series of manganese ferrite-silica nanocomposites with the composition xMnFe2O4-(100-x)SiO2 (x=100, 20, 15 and 10 in mol%) were prepared by the auto combustion method. The physical parameters obtained from this study showed the great potential of the silica-manganese ferrite nanocomposites for the proposed applications as well other suggested future works.
In addition, a preliminary study on the synthesis by the Pechini method and characterization of iron oxide was carried out. The structure, the magnetic properties and the electric conduction mechanism of the prepared iron oxide polycrystallites were investigated leaving open other possible applications industries.<br>Nas últimas décadas grande atenção tem sido dedicada ao estudo de nanopartículas à base de óxido de ferro revestidas por materiais dielétricos orgânicos ou inorgânicos com potencial para aplicações biomédicas e na indústria de absorventes de microondas.
O presente trabalho de doutoramento centra-se na fabricação de nanopartículas de óxido de ferro e no seu revestimento com sílica na forma de uma estrutura núcleo-casca com o objectivo de obter propriedades magnéticas e elétricas interessantes para aplicações práticas na área biomédica e na indústria de microondas. O estudo combinado das propriedades elétricas e magnéticas dos compósitos de óxido de ferro-sílica permitiu estudar as características para aplicações em nova geração de absorventes de micro-ondas de alta eficiência e também agentes com possíveis utilizações em hipertermia e libertação de drogas.
Neste contexto foram utilizados, quatro métodos de síntese: método de sol-gel, técnica fusão de zona flutuante com laser (LFZ), autocombustão e método de Pechini na preparação dos compósitos à base de óxido de ferro / sílica.
Vários estudos como caracterização estrutural, morfológica, elétrica e magnética, foram realizados nas amostras preparadas. A utilização de várias técnicas de caracterização experimental fornece um conhecimento abrangente das propriedades físicas destes materiais e permite perspectivar o possível emprego destes compósitos para aplicações biomédicas e como materiais absorventes de micro-ondas no futuro.
Foi preparada a série de vidros xFe2O3- (100-x) SiO2 (x = 1, 2, 10, 20 em mol%) pelo método de rota sol-gel. O efeito das condições de tratamento
térmico e da relação Fe / Si na morfologia, propriedades elétricas e magnéticas das cerâmicas vítreas foi investigado.
Fibras com a composição 10Fe2O3-90SiO2 foram processadas pela técnica de LFZ. A sua morfologia, estrutura, propriedades magnéticas e estado de redução foram estudadas em função da taxa de extração da preparação das amostras. Foi realizada uma análise exaustiva dos resultados da espectroscopia de Raman e uma pesquisa da microestrutura magnética local para melhor interpretar as características magnéticas das fibras.
Uma série de nanocompósitos de silício-ferrite de manganês com a composição xMnFe2O4- (100-x) SiO2 (x = 100, 20, 15 e 10 em % molar) foi preparada pelo método de auto-combustão. Foi realizada investigação das propriedades estruturais, morfológicas, elétricas e magnéticas destas amostras. Os parâmetros físicos obtidos a partir desse estudo mostraram o grande potencial dos nanocompósitos de silício-ferrita de manganês para as aplicações propostas assim como para o trabalho futuro sugerido.
Além disso, também foi realizado um estudo preliminar sobre a síntese e caracterização do óxido de ferro pelo método de Pechini.A estrutura, as propriedades magnéticas, o mecanismo de condução elétrica das policristalitas de óxido de ferro preparados foram realizadas deixando em aberto outras possíveis aplicações industriais.<br>Programa Doutoral em Engenharia Física
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Zhang, Yi. "Atomistic and finite element modeling of zirconia for thermal barrier coating applications." Thesis, 2014. http://hdl.handle.net/1805/6191.
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Indiana University-Purdue University Indianapolis (IUPUI)<br>Zirconia (ZrO2) is an important ceramic material with a broad range of applications. Due to its high melting temperature, low thermal conductivity, and high-temperature stability, zirconia based ceramics have been widely used for thermal barrier coatings (TBCs). When TBC is exposed to thermal cycling during real applications, the TBC may fail due to several mechanisms: (1) phase transformation into yttrium-rich and yttrium-depleted regions, When the yttrium-rich region produces pure zirconia domains that transform between monoclinic and tetragonal phases upon thermal cycling; and (2) cracking of the coating due to stress induced by erosion. The mechanism of erosion involves gross plastic damage within the TBC, often leading to ceramic loss and/or cracks down to the bond coat. The damage mechanisms are related to service parameters, including TBC material properties, temperature, velocity, particle size, and impact angle.
The goal of this thesis is to understand the structural and mechanical properties of the thermal barrier coating material, thus increasing the service lifetime of gas turbine engines. To this end, it is critical to study the fundamental properties and potential failure mechanisms of zirconia. This thesis is focused on investigating the structural and mechanical properties of zirconia. There are mainly two parts studied in this paper, (1) ab initio calculations of thermodynamic properties of both monoclinic and tetragonal phase zirconia, and monoclinic-to-tetragonal phase transformation, and (2) image-based finite element simulation of the indentation process of yttria-stabilized zirconia.
In the first part of this study, the structural properties, including lattice parameter, band structure, density of state, as well as elastic constants for both monoclinic and tetragonal zirconia have been computed. The pressure-dependent phase transition between tetragonal (t-ZrO2) and cubic zirconia (c-ZrO2) has been calculated using the density function theory (DFT) method. Phase transformation is defined by the band structure and tetragonal distortion changes. The results predict a transition from a monoclinic structure to a fluorite-type cubic structure at the pressure of 37 GPa. Thermodynamic property calculations of monoclinic zirconia (m-ZrO2) were also carried out. Temperature-dependent heat capacity, entropy, free energy, Debye temperature of monoclinic zirconia, from 0 to 1000 K, were computed, and they compared well with those reported in the literature. Moreover, the atomistic simulations correctly predicted the phase transitions of m-ZrO2 under compressive pressures ranging from 0 to 70 GPa. The phase transition pressures of monoclinic to orthorhombic I (3 GPa), orthorhombic I to orthorhombic II (8 GPa), orthorhombic II to tetragonal (37 GPa), and stable tetragonal phases (37-60 GPa) are in excellent agreement with experimental data. In the second part of this study, the mechanical response of yttria-stabilized zirconia under Rockwell superficial indentation was studied. The microstructure image based finite element method was used to validate the model using a composite cermet material. Then, the finite element model of Rockwell indentation of yttria-stabilized zirconia was developed, and the result was compared with experimental hardness data.
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Lepule, Masego Liberty. "Tribo-corrosion characteristics of laser deposited titanium-based smart coatings." 2013. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001018.
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M. Tech. Department of Chemical and Metallurgical Engineering.<br>Aims to understand and study the tribology and tribocorrosion behaviour of the adaptive titanium-nickel-zirconia composite coatings deposited on AISI 316 stainless steel using laser surface deposition technique under various laser processing speeds. The research aim is meant to be achieved through the following objectives: 1. Determine appropriate procedure for laser feedstock deposition ; 2. Investigate tribological performance of laser composites under various loads ; 3. Evaluate the corrosion of the laser composites coatings. and 4. Assess tribocorrosion behavior of the composite coatings
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Rajachidambaram, Meena Suhanya. "Investigation of oxide semiconductor based thin films : deposition, characterization, functionalization, and electronic applications." Thesis, 2011. http://hdl.handle.net/1957/26524.
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Nanostructured ZnO films were obtained via thermal oxidation of thin films formed with metallic Zn-nanoparticle dispersions. Commercial zinc nanoparticles used for this work were characterized by microscopic and thermal analysis methods to analyze the Zn-ZnO core shell structure, surface morphology and oxidation characteristics. These dispersions were spin-coated on SiO₂/Si substrates and then annealed in air between 100 and 600 °C. Significant nanostructural changes were observed for the resulting films, particularly those from larger Zn nanoparticles. These nanostructures, including nanoneedles and nanorods, were likely formed due to fracturing of ZnO outer shell due to differential thermal expansion between the Zn core and the ZnO shell. At temperatures above 227 °C, the metallic Zn has a high vapor pressure leading to high mass transport through these defects. Ultimately the Zn vapor rapidly oxidizes in air to form the ZnO nanostructures. We have found that the resulting films annealed above 400 °C had high electrical resistivity. The zinc nanoparticles were incorporated into zinc indium oxide solution and spin-coated to form thin film transistor (TFT) test structures to evaluate the potential of forming nanostructured field effect sensors using simple solution processing.
The functionalization of zinc tin oxide (ZTO) films with self-assembled monolayers (SAMs) of n-hexylphosphonic acid (n-HPA) was investigated. The n-HPA modified ZTO surfaces were characterized using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and electrical measurements. High contact angles were obtained suggesting high surface coverage of n-HPA on the ZTO films, which was also confirmed using XPS. The impact of n-HPA functionalization on the stability of ZTO TFTs was investigated. The n-HPA functionalized ZTO TFTs were either measured directly after drying or after post-annealing at 140 °C for 48 hours in flowing nitrogen. Their electrical characteristics were compared with that of non-functionalized ZTO reference TFTs fabricated using identical conditions. We found that the non-functionalized devices had a significant turn-on voltage (V[subscript ON]) shift of ~0.9 V and ~1.5 V for the non-annealed and the post-annealed conditions under positive gate bias stress for 10,000 seconds. The n-HPA modified devices showed very minimal shift in V[subscript ON] (0.1 V), regardless of post-thermal treatment. The VON instabilities were attributed to the interaction of species from the ambient atmosphere with the exposed ZTO back channel during gate voltage stress. These species can either accept or donate electrons resulting in changes in the channel conductance with respect to the applied stress.<br>Graduation date: 2012<br>Access restricted to the OSU Community at author's request from Jan. 6, 2012 - Jan. 6, 2013
Books on the topic "Yttrium oxide based coating"
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Kinnunen, Petri. Electrochemical characterisation and modelling of passive films on Ni- and Fe-based alloys. Technical Research Centre of Finland, 2002.
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DellaCorte, Christopher. The evaluation of a modified chrome oxide based high temperature solid lubricant - coating for foil gas bearing. National Aeronautics and Space Administration, Lewis Research Center, 1998.
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Moi, Yeoh Lee. Phase formation and superconductivity in copper oxide based YBCO and RU-1212 and RU-1222 systems prepared by sol-gel and coprecipitation techniques. Nova Science Publishers, 2011.
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Kapustin, Vladimir, and Illarion Li. Theory, electronic structure and physical chemistry of materials cathodes for microwave devices. INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1041298.
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In the monograph the kinetic theory of cathode materials based on metal and oxide phases, analytical methods of research of the cathodes, methods of study of their emission properties. Details the authors discuss the theory and physico-chemistry of oxide-Nickel, metalloplastic, and metal alloyed oxide-yttrium cathodes, including a cathode for magnetrons with cold start.
 Designed for scientific and engineering-technical workers, specializing in electronic materials and electronic devices.
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Center, Lewis Research, ed. The evaluation of a modified chrome oxide based high temperature solid lubricant - coating for foil gas bearing. National Aeronautics and Space Administration, Lewis Research Center, 1998.
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A, Laskowski J., and United States. National Aeronautics and Space Administration., eds. Tribological evaluation of PS300: A new chrome oxide based solid lubricant coating sliding against A1₂0₃ from 25 to 650⁰C. National Aeronautics and Space Administration, 1996.
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Tribological evaluation of PS300: A new chrome oxide based solid lubricant coating sliding against A1₂0₃ from 25 to 650⁰C. National Aeronautics and Space Administration, 1996.
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Tribological evaluation of PS300: A new chrome oxide based solid lubricant coating sliding against A1₂0₃ from 25 to 650⁰C. National Aeronautics and Space Administration, 1996.
Find full textBook chapters on the topic "Yttrium oxide based coating"
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Ata, Fatma Kubra, Seda Yalçınkaya, and Serap Yalcin. "The Design, Synthesis, Characterization of Iron Oxide-Based Coating-Based Nanoproducts." In Handbook of Consumer Nanoproducts. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-6453-6_56-1.
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Lee, Kee Sung, Tae Ho Shin, Shi Woo Lee, Sang Kuk Woo, Jae Kyo Yang, and Yong Ho Choa. "Surface Coating of Reactive Layer with Inner Nano-Pores on Lantanium Gallium Based Oxide." In Materials Science Forum. Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-966-0.161.
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Fu, Yi, Xin Hua Ji, and Yu Wen Qin. "Experimental Study of Micro Displacement Field of Microstate of Crack Tips of Ceramics Plasticized with Zirconia and Stabilized by Yttrium Oxide – Application of Digital Image Correlation Method Based on Analysis by Scanning Electron Microscope." In Key Engineering Materials. Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-410-3.2436.
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Jucha, Sebastian Oliwer, and Grzegorz Jan Moskal. "Thermal Barrier Coatings on the Base of Samarium Zirconates." In Production, Properties, and Applications of High Temperature Coatings. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-4194-3.ch004.
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The zirconates of rare earth elements, such as Sm2Zr2O7, can be an alternative material for zirconia modified by yttria (8YSZ) usually used as an insulation layer in thermal barrier coatings (TBC) systems. This chapter describes the morphology of feedstock zirconate powder, internal morphology and selected properties of different samarium zirconate TBC systems. These included: composite TBC coatings of Sm2Zr2O7 + 8YSZ type with different ratio of both used to coatings deposition powders (25/75, 50/50 and 75/25) as well as the TBC of double ceramic layer (DCL) type with an 8YSZ internal layer and an outer layer of Sm2Zr2O7 type, and a monolayer TBC based on Sm2Zr2O7. Another presented subject is related to the oxidation resistance of TBC systems during static oxidation test at temperature 1100°C. In this case, the special emphasis was taken on the characterization of thermally grown oxides (TGO) zone thickness where the most important phenomena related with overall live-time of TBC systems usually take place.
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Mishra, Trilochan, Manmatha Mahato, and Shashi Kant Tiwari. "Oxide-based self-cleaning and corrosion protective coatings." In Handbook of Modern Coating Technologies. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-444-63237-1.00005-x.
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Pathak, Trilok K., R. E. Kroon, L. P. Purohit, and Hendrik C. Swart. "Highly luminescent ZnO based upconversion thin films grown by sol-gel spin coating." In Spectroscopy of Lanthanide Doped Oxide Materials. Elsevier, 2020. http://dx.doi.org/10.1016/b978-0-08-102935-0.00009-5.
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Hoang Nam, Nguyen. "Multifunctional Silver Nanoparticles: Synthesis and Applications." In Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96712.
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Multifunctional silver nanoparticles have attracted widely due to their potential applications. Based on the properties of individual silver nanoparticles, such as plasmonic and antibacterial properties, silver nanoparticles can become multifunctional by surface modifications with various surfactants or they can be combined in core-shell and composite structures with the magnetic nanoparticles to form bifunctional nanoparticles. After reviewing the methods of synthesis and applications of silver nanoparticles, the chapter describes the synthesis and the properties of the new types of multifunctional silver nanomaterials based on the plasmonic behaviors of silver nanoparticles and the iron oxide Fe3O4 superparamagnetic nanoparticles. One type is a simple combination of silver nanoparticles and iron oxide nanoparticles in a silica matrix Fe3O4/Ag-4ATP@SiO2. Other types are the core-shell structured nanoparticles, where Fe3O4 nanoparticles play as the core and silver nanoparticles are the outer shell, so-called Fe3O4@SiO2-Ag and Fe3O4-Ag. In the Fe3O4@SiO2-Ag, silver nanoparticles are reduced on the surface of silica-coated magnetic core, while in Fe3O4-Ag, silver nanoparticles are directly reduced on the amino groups functionalized on the surface of magnetic nanoparticles without coating with silica. Both of types of the multifunctional silver nanoparticles show the plasmonic and magnetic properties similar as the individual silver and iron oxide nanoparticles. Finally, some applications of those multifunctional silver nanoparticles will be discussed.
Conference papers on the topic "Yttrium oxide based coating"
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Tannenbaum, J. M., K. Lee, B. S. J. Kang, and M. A. Alvin. "Non-Destructive Thermal Barrier Coating Spallation Prediction by a Load-Based Micro-Indentation Technique." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-37696.
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Currently, the durability and life cycle of thermal barrier coatings (TBC) applied to gas turbine blades and combustor components are limiting the maximum temperature and subsequent efficiency at which gas turbine engines operate. The development of new materials, coating technologies and evaluation techniques is required if enhanced efficiency is to be achieved. Of the current ceramic coating materials used in gas turbine engines, yttria stabilized zirconia (YSZ) is most prevalent, its low thermal conductivity, high thermal expansion coefficient and outstanding mechanical strength make it ideal for use in TBC systems. However, residual stresses caused by coefficients of thermal expansion mismatches within the TBC system and unstable thermally grown oxides are considered the primary causes for its premature and erratic spallation failure. Through finite element simulations, it is shown that the residual stresses generated within the thermally grown oxide (TGO), bond coat (BC), YSZ and their interfaces create slight variations in indentation unloading surface stiffness response prior to spallation failure. In this research, seven air plasma sprayed and one electron beam physical vapor deposition yttria partially stabilized zirconia TBCs were subjected to isothermal and cyclic loadings at 1100°C. The associated coating degradation was evaluated using a non-destructive multiple partial unloading micro-indentation procedure. The results show that the proposed non-destructive micro-indentation evaluation technique can be an effective and specimen-independent TBC failure prediction tool capable of determining the location of initial spallation failure prior to its actual occurrence.
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Podob, Mark. "Chemical Vapor Deposition (CVD) Coatings for Protection of Jet Engine Components." In ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/93-gt-375.
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CVD coatings are thin films resulting from the chemical reaction between a gaseous phase and the heated surface of a substrate. Among the industries using CVD coating technology are electronics, tooling, fuel cogeneration, and aerospace. The electronics industry uses CVD to deposit semiconductor materials onto different substrates. For the tooling industry, titanium nitride (TiN), titanium carbide (TiC), or aluminum oxide (Al2O3) is deposited onto cutting or metal forming tools. These hardcoatings act as chemical and thermal barriers between the tool and workpiece. In the aerospace industry, CVD is used to deposit aluminide or chromide coatings onto jet engine blades and other hot section components. The coatings improve the corrosion and oxidation resistance of the base metal. CVD is replacing older established methods for protecting these same components. While the use of CVD coatings in the aerospace industry is relatively new, it is gaining increasing acceptance. In addition to producing aluminides and chromides, CVD reactions can form coatings containing silicon, yttrium, hafnium and other rare earth elements. Since the coatings are the result of the chemical reaction between high purity gases and solids, coatings can be free of porosity and inclusions.
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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).
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Ford, David A., Keith P. L. Fullagar, Harry K. Bhangu, et al. "Improved Performance Rhenium Containing Single Crystal Alloy Turbine Blades Utilising PPM Levels of the Highly Reactive Elements Lanthanum and Yttrium." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-371.
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Turbine inlet temperatures have now approached 1650°C (3000°F) at maximum power for the latest large commercial turbofan engines, resulting in high fuel efficiency and thrust levels approaching or exceeding 445 kN (100,000 lbs.). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements. This level of performance has been brought about by a combination of advances in air cooling for turbine blades and vanes, computerized design technology for stresses and airflow and the development and application of rhenium (Re) containing, high γ′ volume fraction nickel-base single crystal superalloys, with advanced coatings, including prime-reliant ceramic thermal barrier coatings (TBCs). Re additions to cast airfoil superalloys not only improve creep and thermo-mechanical fatigue strength but also environmental properties, including coating performance. Re slows down diffusion in these alloys at high operating temperatures.(1) At high gas temperatures, several issues are critical to turbine engine performance retention, blade life and integrity. These are tip oxidation in particular for shroudless blades, internal oxidation for lightly cooled turbine blades and TBC adherence to both the airfoil and tip seal liner. It is now known that sulfur (S) at levels < 10 ppm but > 0.2 ppm in these alloys reduces the adherence of α alumina protective scales on these materials or their coatings by weakening the Van der Waal’s bond between the scale and the alloy substrate. A team approach has been used to develop an improvement to CMSX-4® alloy which contains 3% Re, by reducing S and phosphorus (P) levels in the alloy to < 2 ppm, combined with residual additions of lanthanum (La) + yttrium (Y) in the range 10–30 ppm. Results from cyclic, burner rig dynamic oxidation testing at 1093°C (2000°F) show thirteen times the number of cycles to initial alumina scale spallation for CMSX-4 [La + Y] compared to standard CMSX-4. A key factor for application acceptance is of course manufacturing cost. The development of improved low reactivity prime coats for the blade shell molds along with a viable, tight dimensional control yttrium oxide core body are discussed. The target is to attain grain yields of single crystal CMSX-4 (ULS) [La + Y] turbine blades and casting cleanliness approaching standard CMSX-4. The low residual levels of La + Y along with a sophisticated homogenisation/solutioning heat treatment procedure result in full solutioning with essentially no residual γ/γ′ eutectic phase, Ni (La, Y) low melting point eutectics and associated incipient melting pores. Thus, full CMSX-4 mechanical properties are attained. The La assists with ppm chemistry control of the Y throughout the single crystal turbine blade castings through the formation of a continuous lanthanum oxide film between the molten and solidifying alloy and the ceramic core and prime coat of the shell mold. Y and La tie up the < 2 ppm but > 0.2 ppm residual S in the alloy as very stable Y and La sulfides and oxysulfides, thus preventing diffusion of the S atoms to the alumina scale layer under high temperature, cyclic oxidising conditions. La also forms a stable phosphide. CMSX-4 (ULS) [La + Y] HP shroudless turbine blades will commence engine testing in May 1998.
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Nickel, Hubertus, Willem J. Quadakkers, and Lorenz Singheiser. "Determination of Corrosion Layers and Protective Coatings on Steels and Alloys Used in Simulated Service Environment of Modern Power Plants." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2249.
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The development of modern power generation systems with higher thermal efficiency requires the use of constructional materials of higher strength and improved resistance to the aggressive service atmospheres. In this paper the following examples are discussed: 1) The oxidation behavior of 9% Cr steels in simulated combustion gases: The effects of O2 and H2O content on the oxidation behavior of 9% Cr steels in the temperature range 600–800°C showed that in dry oxygen a protective scale was formed with an oxidation rate controlled by diffusion. In contrast, that in the presence of water vapor, after an incubation period, the scale became non-protective as a result of a change in the oxidation mechanism. 2) The development of NiCrAlY alloys for corrosion resistant coatings and thermal barrier coatings of gas turbine components: The increase of component surface temperature in modern gas turbines leads to an enhanced oxidation attack of the blade coating. Considerable efforts have been made in the improvement of the temperature properties of MCrAlY coatings by the additions of minor elements like yttrium, silicon and titanium. The experimental results show the positive, but different influence of the oxidation behavior of the MCrAlY coatings by the addition of these minor elements. 3) The development of light-weight intermetallics of TiAl-basis: TiAl-based intermetallics are promising materials for future turbine components because of the combination of high temperature strength and low density. These alloys, however, possess poor oxidation resistance at temperatures above 700°C. The experimental results showed that the oxidation behavior of TiAl-based intermetallics can be strongly improved by minor additions of 1–2 at.-% silver. 4) The oxide dispersion strengthened (ODS) alloys provide excellent creep resistance up to much higher temperatures than can be achieved with conventional wrought or cast alloys in combination with suitable high temperature oxidation/corrosion resistance. The growth mechanisms of protective chromia and alumina scales were examined by a two-stage oxidation method with 18O tracer. The distribution of the oxygen isotopes in the oxide scale was determined by SIMS and SNMS. The results show the positive influence of a Y2O3 dispersion on the oxidation resistance of the ODS alloys and its effect on growth mechanisms.
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Toma, Filofteia-Laura, Julia Sagel, Christoph Leyens, Karel Slámečka, Serhii Tkachenko, and Ladislav Čelko. "Influence of Bondcoat Topography on the Properties of Suspension Sprayed YSZ Thermal Barrier Coatings." In ITSC2021, edited by F. Azarmi, X. Chen, J. Cizek, et al. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.itsc2021p0009.
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Abstract Intensive R&D work of more than one decade has demonstrated many unique coating properties; particularly for oxide ceramic coatings fabricated by suspension thermal spraying technology. Suspension spraying allows producing yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) with columnar microstructure; similar to those produced by electron-beam physical vapor deposition (EB-PVD); and vertically cracked morphologies; with a generally low thermal conductivity. Therefore; suspension sprayed YSZ TBCs are seen as an alternative to EB-PVD coatings and those produced by conventional air plasma spray (APS) processes. Nonetheless; the microstructure of the YSZ topcoat is strongly influenced by the properties of the metallic bondcoat. In this work; direct laser interference patterning (DLIP) was applied to texture the surface topography of Ni-alloy based plasma sprayed bondcoat. Suspension plasma spraying (SPS) was applied to produce YSZ coatings on top of as-sprayed and laser-patterned bondcoat. The samples were characterized in terms of microstructure; phase composition and thermal cycling performance. The influence of the bondcoat topography on the properties of suspension sprayed YSZ coatings is presented and discussed.
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Prakash, Deep, Raja K. Lenka, A. K. Sahu, P. K. Patro, P. K. Sinha, and A. K. Suri. "Effect of Cathode Functional Layer on the Electrical Performance of Tubular Solid Oxide Fuel Cell." In ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33352.
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Development of technology related to solid oxide fuel cells at Materials Group, BARC includes synthesis of materials viz. lanthanum strontium manganite (LSM), yttria stabilized zirconia (YSZ), NiO etc. using chemical methods followed by shaping components and integrating into single cells. The indigenously prepared materials are converted to single cells for studies on material characterization and cell performances. This paper presents results of studies on electrical performances of tubular solid oxide fuel cell under hydrogen and oxygen atmospheres and correlates them with the use of cathode functional layers. Studies on symmetrical cells comprising of YSZ electrolyte sandwiched between cathode layers were carried out using electrical impedance spectroscopy (EIS). The EIS results exhibit improvement of area specific resistance (ASR) on incorporation of functional layers. Based on EIS data, double functional layers with varying compositions were incorporated in button cells as well as tubular single cells. Two types of tubular cells were fabricated, electrolyte supported and cathode supported. The electrolyte supported tubular cells were fabricated by making one-end closed tubes of YSZ, followed by coating with porous LSM inside and porous NiO-YSZ layer outside the tubes. On the other hand, tubular cathode supported cells were fabricated by one-end closed porous LSM tubes, followed by subsequent coatings of electrolyte and anode. The cells were characterized for electrical performance from 800 to 1000°C. Electrical power output from electrolyte supported cells with cathode functional layers increased from 300 mW per cell to 500 mW per cell. On the other hand, cathode supported cells exhibited improvement in ASR from ∼ 2 Ωcm2 to &lt; 1 Ωcm2. The results were correlated with microstructure, area of triple phase boundaries and catalytic activity of cathode.
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Rai, Pratyush, Prashanth S. Kumar, Vijay K. Varadan, Paul Ruffin, Christina Brantley, and Eugene Edwards. "Yttrium oxide based three dimensional metamaterials for visible light cloaking." In SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, edited by Vijay K. Varadan. SPIE, 2014. http://dx.doi.org/10.1117/12.2045216.
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Tawancy, H. M., та Luai M. Al-Hadhrami. "Influence of Titanium in Nickel-Base Superalloys on the Performance of Thermal Barrier Coatings Utilizing γ-γ′ Platinum Bond Coats". У ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22030.
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Titanium is a key element in nickel-base superalloys needed with aluminum to achieve the desired volume fraction of the strengthening γ′-phase. However, depending upon its concentration, titanium can degrade the adherence of aluminum oxide by forming TiO2 particles near the oxidemetal interface. This effect is extended to thermal barrier coating systems where in this case, the bond coat replaces the superalloy as the underlying substrate. Noting that the onset of failure of thermal barrier coating systems coincides with the first spall of the thermally grown oxide, titanium level in the superalloy can have an important effect on the useful life of the coating. Therefore, this study was undertaken to examine the effect of titanium on the performance of a thermal barrier coating system. Included in the study were two Ni-base superalloys with similar chemical composition except for the Ti content, and a Pt-containing bond coat consisting of γ′+γ-phases all top coated with zirconia stabilized by 7 weight % yttria. Coating performance was evaluated from thermal exposure tests at 1150 °C with a 24-hour cycling period to room temperature. Various electron-optical techniques were used to characterize the microstructure. The coating system on the low-Ti alloy was found to outperform that on the high-Ti alloy. However, for both alloys, failure was observed to occur by loss of adhesion between the thermally-grown oxide and underlying bond coat.
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Sobolewski, Roman, Donald P. Butler, and Zeynep Celik-Butler. "Cooled and uncooled infrared detectors based on yttrium barium copper oxide." In Advanced Optical Materials and Devices, edited by Steponas P. Asmontas and Jonas Gradauskas. SPIE, 2001. http://dx.doi.org/10.1117/12.417599.
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