Zeitschriftenartikel: „Yttrium oxide based coating“

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Park, Seung Hyun, Kyung Eon Kim und Sang Jeen Hong. „Surface Analysis of Chamber Coating Materials Exposed to CF4/O2 Plasma“. Coatings 11, Nr. 1 (18.01.2021): 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 und G. ZAMBRANO. „HOT CORROSION OF YTTRIUM STABILIZED ZIRCONIA COATINGS DEPOSITED BY AIR PLASMA SPRAY ON A NICKEL-BASED SUPERALLOY“. Surface Review and Letters 24, Nr. 06 (24.11.2016): 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, und Edson Costa Santos. „Structure of NiCrAlY Coatings Deposited on Oriented Single Crystal Superalloy Substrates by Laser Cladding“. Advanced Materials Research 278 (Juli 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 und Xuan Hui Qu. „Effect of Y₂O₃ Coating on the Interface and Mechanical Properties of SiC Fiber Reinforced GH4738 Composites“. Materials Science Forum 898 (Juni 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 und Olivier Guillon. „Environmental Barrier Coatings Made by Different Thermal Spray Technologies“. Coatings 9, Nr. 12 (22.11.2019): 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 und 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 (Januar 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 und T. Miyazaki. „Cooperation of Phosphate Monomer and Silica Modification on Zirconia“. Journal of Dental Research 87, Nr. 7 (Juli 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 und 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, Nr. 12 (11.03.2019): 11736–42. http://dx.doi.org/10.1021/acsami.8b21325.

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Molin, S., Å. H. Persson, T. L. Skafte, A. L. Smitshuysen, S. H. Jensen, K. B. Andersen, H. Xu, M. Chen und P. V. Hendriksen. „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 und Robert A. Miller. „Refractory Oxide Coatings on SiC Ceramics“. MRS Bulletin 19, Nr. 10 (Oktober 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.

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Durand, C., C. Vallée, C. Dubourdieu, M. Kahn, M. Derivaz, S. Blonkowski, D. Jalabert, P. Hollinger, Q. Fang und I. W. Boyd. „Electrical property improvements of yttrium oxide-based metal-insulator-metal capacitors“. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 24, Nr. 3 (Mai 2006): 459–66. http://dx.doi.org/10.1116/1.2190649.

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Wright, I. G., und B. A. Pint. „Bond coating issues in thermal barrier coatings for industrial gas turbines“. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 219, Nr. 2 (01.03.2005): 101–7. http://dx.doi.org/10.1243/095765005x6836.

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Thermal barrier coatings are intended to work in conjunction with internal cooling schemes to reduce the metal temperature of critical hot gas path components in gas turbine engines. The thermal resistance is typically provided by a 100-250 μm thick layer of ceramic (most usually zirconia stabilized with an addition of 7–8 wt% of yttria), and this is deposited on to an approximately 50 μ thick, metallic bond coating that is intended to anchor the ceramic to the metallic surface, to provide some degree of mechanical compliance, and to act as a reservoir of protective scale-forming elements (Al) to protect the underlying superalloy from high-temperature corrosion. A feature of importance to the durability of thermal barrier coatings is the early establishment of a continuous, protective oxide layer (preferably α-alumina) at the bond coating—ceramic interface. Because zirconia is permeable to oxygen, this oxide layer continues to grow during service. Some superalloys are inherently resistant to high-temperature oxidation, so a separate bond coating may not be needed in those cases. Thermal barrier coatings have been in service in aeroengines for a number of years, and the use of this technology for increasing the durability and/or efficiency of industrial gas turbines is currently of significant interest. The data presented were taken from an investigation of routes to optimize bond coating performance, and the focus of the paper is on the influences of reactive elements and Pt on the oxidation behaviour of NiAl-based alloys determined in studies using cast versions of bond coating compositions.

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Firouzdor, Vahid, Lucas Wilson, Kumar Sridharan, Brandon Semerau, Benjamin Hauch, Jamieson Brechtl, James I. Cole und Todd R. Allen. „Development of Diffusion Barrier Coatings for Mitigation of Fuel-Cladding Chemical Interactions“. Key Engineering Materials 507 (März 2012): 3–7. http://dx.doi.org/10.4028/www.scientific.net/kem.507.3.

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Fuel Cladding Chemical Interactions (FCCI) in a nuclear reactor occur due to thermal and radiation enhanced inter-diffusion between the cladding and fuel materials, and can have the detrimental effects of reducing the effective cladding wall thickness and the formation of low melting point eutectic compounds. Deposition of diffusion barrier coatings of a thin oxide on the inner surface of the cladding can potentially reduce or delay the onset of FCCI. This study examines the feasibility of using nanofluid-based electrophoretic deposition (EPD) process to deposit coatings of titanium oxide, yttria-stabilized zirconia (YSZ) and vanadium oxide. The deposition parameters, including the nanofluid composition, current, and voltage were optimized for each coating material using test flat substrates of T91 ferritic-martensitic steel. Diffusion characteristics of the coatings were investigated by diffusion couple experiments using the fuel surrogate cerium. These diffusion couple studies performed in the temperature range of 560°C and 585°C showed that the oxide coatings significantly reduce the solid state inter-diffusion between cerium to steel.

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Chen, Liang-Yu. „Improvement of Dielectric Performance of a Prototype AlN High Temperature Chip-level Package“. Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, HITEN (01.01.2011): 000052–57. http://dx.doi.org/10.4071/hiten-paper3-lchen.

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Aluminum nitride (AlN) has been proposed as a packaging substrate material for reliable high temperature electronics operating in a wide temperature range. However, it was discovered in a recent study that the dielectric properties of some commercial polycrystalline AlN materials change quite significantly with temperature at high temperatures. These material properties resulted in undesired large and temperature-dependent parasitic parameters for a prototype chip-level package based on an AlN substrate with the yttrium oxide dopant. This paper reports a method using a coating layer of a commercial thick-film glass on the AlN substrate surface to significantly reduce both the parasitic capacitances and parasitic conductances between neighboring inputs/outputs (I/Os) of a prototype AlN chip-level package. The parasitic parameters of 8-I/Os low power chip-level packages with the insulating glass coating were characterized at frequencies from 120 Hz to 1 MHz between room temperature and 500°C. These results were compared with the parameters of AlN packages without the glass coating. The results indicate that the parasitic capacitances and conductances between I/Os of the improved prototype AlN packages are significantly reduced and stable at high temperatures. The method using a glass coating provides a feasible way to mitigate the temperature dependence of dielectric properties of AlN and further utilize AlN as a reliable packaging substrate material for high temperature applications.

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Goto, Takashi. „Laser CVD Process for High Speed Deposition of YSZ Films“. Materials Science Forum 475-479 (Januar 2005): 1213–18. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1213.

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Thick oxide coatings have wide ranged applications such as oxidation protection, abrasives and thermal barrier coating (TBC). Yttria stabilized zirconia (YSZ) has been used for TBC in gas turbines. Generally, atmospheric plasma spray (APS) and electron-beam physical vapor deposition (EB-PVD) have been utilized in practical applications. Although chemical vapor deposition (CVD) provides high quality coatings, the deposition rate of CVD could have been too small for TBCs. We have recently developed a new laser CVD process achieving an extremely high deposition rate up to 660 ım/h for YSZ coatings on Al2O3 substrates and Ni-based super alloy substrates using Zr(dpm)4 and Y(dpm)3 precursors. An Nd:YAG laser with a high power of 250 W was introduced in a CVD chamber as a defocused beam in a diameter of 20mm covering a whole substrate surface. The YSZ coatings had a well-grown columnar structure with significant (200) orientation. Other oxides such as Y2O3, Al2O3 and TiO2 films were also prepared by laser CVD at high deposition rates around 1 mm/h.

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Sohal, Manreet Kaur, Aman Mahajan, Sahil Gasso, R. K. Bedi, Ravi Chand Singh, A. K. Debnath und D. K. Aswal. „Ultrasensitive yttrium modified tin oxide thin film based sub-ppb level NO2 detector“. Sensors and Actuators B: Chemical 329 (Februar 2021): 129169. http://dx.doi.org/10.1016/j.snb.2020.129169.

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Jasik, A. „The Numerical Modeling of Thermal Stress Distribution in Thermal Barrier Coatings“. Archives of Metallurgy and Materials 62, Nr. 3 (26.09.2017): 1433–37. http://dx.doi.org/10.1515/amm-2017-0221.

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Abstract The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ) and apply pyrochlore type material with formula La2Zr2O7. The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.

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Xu, Xing Yan, Chang Rong Xia, Shou Guo Huang und Guang Yao Meng. „Intermediate-Temperature Solid Oxide Fuel Cells with Y_0.25Bi_0.75O_1.5-Ag Cathodes“. Materials Science Forum 475-479 (Januar 2005): 1157–60. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1157.

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Composites consisting of silver and yttria-stabilized bismuth oxide (YSB) were fabricated and investigated as cathodes for intermediate-temperature solid oxide fuel cells (SOFCs) with thin electrolyte films of yttria-stabilized zirconia (YSZ). The films were deposited using spin coating with YSZ suspension. Comparison of YSB-Ag and conventional La0.8Sr0.2MnO3 (LSM) based cathodes showed that the YSB-Ag composite has better electrochemical performance; Interfacial polarization resistance of YSB-Ag cathode is 0.13 Ωcm2 at 750oC. Power density of the single cell with YSB-Ag cathode was about 535 mW/cm2 at 750oC, while that with LSM-Sm0.2Ce0.8O1.9 cathode was only 329 mW/cm2.

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Marple, Basil R., Joël Voyer, Michel Thibodeau, Douglas R. Nagy und Robert Vassen. „Hot Corrosion of Lanthanum Zirconate and Partially Stabilized Zirconia Thermal Barrier Coatings“. Journal of Engineering for Gas Turbines and Power 128, Nr. 1 (30.07.2004): 144–52. http://dx.doi.org/10.1115/1.1924534.

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The hot corrosion resistance of lanthanum zirconate and 8wt.% yttria-stabilized zirconia coatings produced by thermal spraying for use as thermal barriers on industrial gas turbines or in aerospace applications was evaluated. The two ceramic oxide coatings were exposed for various periods of time at temperatures up to 1000°C to vanadium- and sulfur-containing compounds, species often produced during the combustion of typical fuels used in these applications. Changes in the coatings were studied using a scanning electron microscope to observe the microstructure and x-ray diffraction techniques to analyze the phase composition. The results showed different behaviors for the two materials: the zirconia-based coating being rapidly degraded by the vanadium compounds and resistant to attack by the sulfur materials while the lanthanum zirconate was less damaged by exposure to vanadia but severely attacked in the presence of sulfur-containing species.

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Nickel, Hubertus, Willem J. Quadakkers und Lorenz Singheiser. „Determination of Corrosion Layers and Protective Coatings on Steels and Alloys Used in Simulated Service Environment of Modern Power Plants“. Journal of Pressure Vessel Technology 128, Nr. 1 (06.10.2005): 130–39. http://dx.doi.org/10.1115/1.2137769.

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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. (i) 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 nonprotective as a result of a change in the oxidation mechanism. (ii) 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, such as 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. (iii) The development of lightweight 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 1-2at.% silver. (iv) 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 O18 tracer. The distribution of the oxygen isotopes in the oxide scale was determined by secondary ion-mass spectroscopy 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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Kokulnathan, Thangavelu, Tzyy-Jiann Wang, Elumalai Ashok Kumar, Nithyadevi Duraisamy und An-Ting Lee. „An electrochemical platform based on yttrium oxide/boron nitride nanocomposite for the detection of dopamine“. Sensors and Actuators B: Chemical 349 (Dezember 2021): 130787. http://dx.doi.org/10.1016/j.snb.2021.130787.

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Fukudome, Takero, Sazo Tsuruzono, Tetsuo Tatsumi, Yoshihiro Ichikawa, Tohru Hisamatsu und Isao Yuri. „Development of Silicon Nitride Components for Gas Turbine“. Key Engineering Materials 287 (Juni 2005): 10–15. http://dx.doi.org/10.4028/www.scientific.net/kem.287.10.

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Silicon nitride is one of the most practical candidates for ceramic gas turbines. The SN282 is silicon nitride material developed by Kyocera for gas turbines. Several new technologies have been developed to achieve materialization of ceramic gas turbines, such as material, fabrication process, evaluation / analysis technology. Recent technology is focused on recession of silicon-based ceramics under combustion gas. Environmental Barrier Coatings (EBCs) are developed to suppress these recession. We have found rare-earth element silicate and yttrium stabilized zirconium oxide (YSZ) have high corrosion resistance to the combustion gas. These materials were applied to the ceramic gas turbine components. The components with EBCs were evaluated in the actual engine tests. We have confirmed that the EBCs effectively work for the recession resistance.

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Okovity, V. A., F. I. Panteleenko, V. V. Okovity, V. M. Astashinsky, V. V. Uglov, V. I. Chimanskiy und N. N. Cerenda. „Formation and Investigation of Plasma Powder Coatings Made of Oxide Ceramics Modified with High-Energy Effects“. Science & Technique 17, Nr. 5 (12.10.2018): 378–89. http://dx.doi.org/10.21122/2227-1031-2018-17-5-378-389.

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The paper presents results of studying structure and properties of multilayer composite coatings optimized for their composition based on zirconium dioxide materials used for deposition of plasma coatings on the models of elements for anti-meteor shielding screens. The influence of plasma jet parameters (current, distance of sputtering, consumption of plasma-forming nitrogen gas) and fractional composition of an initial powder on characteristics of two-layer composite coatings based on nickel-chromium-aluminum-yttrium and zirconium dioxide on the elements of protective screens has been analyzed in the paper. Optimization has been carried out on the basis of obtaining maximum coefficient of powder utilization. The investigations have made it possible to ascertain specific features of elemental and phase composition, surface morphology, microstructure multilayer composite coatings on the basis of a solid layer of metal oxides and a viscous transition sub-layer subjected to compression plasma flows. The investigations have been executed with the help of scanning electron microscopy, energy dispersive x-ray spectral microanalysis, and x-ray diffraction analysis. It has been shown on the basis of the obtained results that the effect of compression plasma flows on multilayer composite coatings leads to a modification of a near-surface layer with a thickness up to 15 μm that presupposes its melting and subsequent high-speed crystallization which together provide an increase in its density, decrease in porosity while maintaining the initial phase state. Liquid-phase processes in the molten phase of the near-surface layer permit to modify morphological properties of the surface which are associated with its smoothing and lowering of roughness.

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He, Jinsong, Anan Cui, Fan Ni, Shihuai Deng, Fei Shen und Gang Yang. „A novel 3D yttrium based-graphene oxide-sodium alginate hydrogel for remarkable adsorption of fluoride from water“. Journal of Colloid and Interface Science 531 (Dezember 2018): 37–46. http://dx.doi.org/10.1016/j.jcis.2018.07.017.

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Mori, Masashi, Hirofumi Sumi und Eisaku Suda. „Reducing the Gadolinium Dopant Content by Partial Substitution with Yttrium in a Ce0.9Gd0.1O1.95-Based Oxide-Ion Conductor“. Journal of The Electrochemical Society 164, Nr. 14 (2017): F1626—F1632. http://dx.doi.org/10.1149/2.1071714jes.

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Jech, David, Pavel Komarov, Michaela Remešová, Lucie Dyčková, Karel Slámečka, Simona Ravaszová, Karel Dvořák und Ladislav Čelko. „Thermal Cyclic Behaviour of Conventional YSZ and Mullite-YSZ Thermal Barrier Coatings“. Defect and Diffusion Forum 405 (November 2020): 417–22. http://dx.doi.org/10.4028/www.scientific.net/ddf.405.417.

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Nowadays commonly used thermal barrier coatings (TBC) are based on yttria stabilized zirconia (YSZ). Addition of mullite phase into the YSZ coating can improve resulting high temperature properties. The contribution focuses on high temperature cyclic oxidation behaviour of two TBC systems with different top coats (TC) deposited by the means of atmospheric plasma spraying. The initial mullite-YSZ powder mixture consisted of 29 vol. % of mullite and 71 vol. % of YSZ. The conventional TBC system consisted of ~ 150 µm thick NiCoCrAlYHfSi bond coat (BC) and ~ 300 µm thick YSZ top coat. The experimental mullite-YSZ (MYSZ) TBC system consisted of ~ 150 µm thick NiCoCrAlYHfSi bond coat, ~ 100 µm thick YSZ interlayer and ~ 200 µm thick mullite-YSZ top coat. The experimental TBC proved higher lifetime, durability and phase stability and also lower grow rate of thermally grown oxide (TGO) compared to conventional TBC. Lifetime, phase stability and changes in the microstructure of TBCs after the furnace cyclic oxidation test were evaluated by the means of scanning electron microscopy equipped with EDX analyzer and X-ray diffraction techniques. Oxidation kinetics of TGO was calculated based on thickness determined utilizing digital image analysis.

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Rose, Lars, Mohan Menon, Kent Kammer, Olivera Kesler und Peter Halvor Larsen. „Processing of Ce_1-xGd_xO_2-δ (GDC) Thin Films from Precursors for Application in Solid Oxide Fuel Cells“. Advanced Materials Research 15-17 (Februar 2006): 293–98. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.293.

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Extensive interfacial reactions are known to occur between Fe-Co based perovskite cathode materials and the standard solid oxide fuel cell (SOFC) yttria stabilized zirconia (YSZ) electrolyte. Thin films of gadolinia doped ceria (GDC) could be used as a diffusion barrier between the cathode and the electrolyte. The present work investigates spin coating thin diffusion reaction inhibiting films onto SOFC electrolytes. The chemical and structural evolution of ethylene glycol based precursor solution is studied by means of rheology, x-ray diffraction (XRD), high temperature XRD (HT-XRD), Fourier-transformed infrared spectroscopy (FTIR) and differential thermal analysis (DTA). The studies show that cerium formate is formed as an intermediate resin. Thin films, up to 500 nm thick, of gadolinia doped ceria (GDC) are successfully produced by multiple spin coating of polymerized ethylene glycol derived solutions on 200 1m thick YSZ tapes. The GDC and YSZ interfacial surface morphology and film thickness are studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). These films are shown to successfully prevent the creation of non-conducting reaction phases at the cathode-electrolyte interface by blocking interdiffusion.

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Mochales, Carolina, Rolf Zehbe, Stefan Frank, Farzaneh Rahimi, Aleksandra Urbanska, Claudia Fleck und Wolf Dieter Müller. „Multilayered Ceramic Constructs Created by EPD“. Key Engineering Materials 654 (Juli 2015): 122–26. http://dx.doi.org/10.4028/www.scientific.net/kem.654.122.

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Zirconia-based ceramics have gained considerable interest for several applications (e.g. solid electrolytes in fuel cells and in oxygen sensors, thermal barrier coatings and biomaterials for dental and orthopaedic applications) due to their high mechanical strength, improved fracture toughness and easy affordability. Zirconia occurs in three crystal modifications at low-pressure conditions: monoclinic, tetragonal and cubic. The monoclinic phase is the natural room temperature stable phase, while the tetragonal and the cubic phase can be stabilized at room temperature by doping with the right amount of some oxide dopants (e.g. CaO, MgO, CeO2and Y2O3). The stabilization of the tetragonal phase results in a remarkable increase in mechanical toughness, whereas the stabilization of the cubic phase results in an increase of the ionic conductivity to values significantly higher than for other ceramics. In order to optimize the properties of the final ceramic by combining the high mechanical toughness of the tetragonal phase of zirconia together with the high ionic conductivity of its cubic phase, we established an EPD layering process with nanometric sized powders of Y-TZP with different mol percentages of yttrium oxide (3 % and 8 %) and produced multilayers of alternating tetragonal and cubic phases with a clearly defined interface. The crack propagation through this interface was studied by means of micro-indentation

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Kumar, Amarnath, Prakash C. Patnaik und Kuiying Chen. „Damage Assessment and Fracture Resistance of Functionally Graded Advanced Thermal Barrier Coating Systems: Experimental and Analytical Modeling Approach“. Coatings 10, Nr. 5 (14.05.2020): 474. http://dx.doi.org/10.3390/coatings10050474.

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Enhancement of stability, durability, and performance of thermal barrier coating (TBC) systems providing thermal insulation to aero-propulsion hot-section components is a pressing industrial need. An experimental program was undertaken with thermally cycled eight wt.% yttria stabilized zirconia (YSZ) TBC to examine the progressive and sequential physical damage and coating failure. A linear relation for parameterized thermally grown oxide (TGO) growth rate and crack length was evident when plotted against parameterized thermal cycling up to 430 cycles. An exponential function thereafter with the thermal cycling observed irrespective of coating processing. A phenomenological model for the TBC delamination is proposed based on TGO initiation, growth, and profile changes. An isostrain-based simplistic fracture mechanical model is presented and simulations carried out for functionally graded (FG) TBC systems to analyze the cracking instability and fracture resistance. A few realistic FG TBCs architectures were considered, exploiting the compositional, dimensional, and other parameters for simulations using the model. Normalized stress intensity factor, K1/K0 as an effective design parameter in evaluating the fracture resistance of the interfaces is proposed. The elastic modulus difference between adjacent FG layers showed stronger influence on K1/K0 than the layer thickness. Two advanced and promising TBC materials were also taken into consideration, namely gadolinium zirconate and lanthanum zirconate. Fracture resistance of both double layer and trilayer hybrid architectures were also simulated and analyzed.

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Byeon, Jai Won, B. Jayaraj und Yong Ho Sohn. „Characterization of Isothermally Oxidized ZrO₂-8wt.%Y₂O₃ Thermal Barrier Coatings by Electrochemical Impedance Spectroscopy“. Materials Science Forum 486-487 (Juni 2005): 145–48. http://dx.doi.org/10.4028/www.scientific.net/msf.486-487.145.

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Electrochemical impedance spectroscopy was employed to examine ZrO2-8wt.%Y2O3 (yttria stabilized zirconia, YSZ) thermal barrier coating (TBC) as a function of isothermal exposure time at 1121°C. Electrochemical impedance response (resistance and capacitance of YSZ and thermally grown oxide (TGO)) of TBC specimens was analyzed with an alternative current equivalent circuit based on the multi-layered micro-constituents of TBC, and the impedance response was correlated with microstructural changes attributed to isothermal oxidation. The resistance of YSZ was observed to increase initially and then decrease with thermal exposure. The initial increase was related to the high temperature sintering of YSZ, and the subsequent decrease was discussed in terms of microcrack initiation and electrolyte penetration. The TGO thickness was linearly correlated to the capacitance of TGO.

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Graves, Christopher, Christodoulos Chatzichristodoulou und Mogens B. Mogensen. „Kinetics of CO/CO2 and H2/H2O reactions at Ni-based and ceria-based solid-oxide-cell electrodes“. Faraday Discussions 182 (2015): 75–95. http://dx.doi.org/10.1039/c5fd00048c.

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The solid oxide electrochemical cell (SOC) is an energy conversion technology that can be operated reversibly, to efficiently convert chemical fuels to electricity (fuel cell mode) as well as to store electricity as chemical fuels (electrolysis mode). The SOC fuel-electrode carries out the electrochemical reactions CO₂ + 2e⁻ ↔ CO + O²⁻ and H₂O + 2e⁻ ↔ H₂ + O²⁻, for which the electrocatalytic activities of different electrodes differ considerably. The relative activities in CO/CO₂ and H₂/H₂O and the nature of the differences are not well studied, even for the most common fuel-electrode material, a composite of nickel and yttria/scandia stabilized zirconia (Ni–SZ). Ni–SZ is known to be more active for H₂/H₂O than for CO/CO₂ reactions, but the reported relative activity varies widely. Here we compare AC impedance and DC current–overpotential data measured in the two gas environments for several different electrodes comprised of Ni–SZ, Gd-doped CeO₂ (CGO), and CGO nanoparticles coating Nb-doped SrTiO₃ backbones (CGOn/STN). 2D model and 3D porous electrode geometries are employed to investigate the influence of microstructure, gas diffusion and impurities. Comparing model and porous Ni–SZ electrodes, the ratio of electrode polarization resistance in CO/CO₂vs. H₂/H₂O decreases from 33 to 2. Experiments and modelling suggest that the ratio decreases due to a lower concentration of impurities blocking the three phase boundary and due to the nature of the reaction zone extension into the porous electrode thickness. Besides showing higher activity for H₂/H₂O reactions than CO/CO₂ reactions, the Ni/SZ interface is more active for oxidation than reduction. On the other hand, we find the opposite behaviour in both cases for CGOn/STN model electrodes, reporting for the first time a higher electrocatalytic activity of CGO nanoparticles for CO/CO₂ than for H₂/H₂O reactions in the absence of gas diffusion limitations. We propose that enhanced surface reduction at the CGOn/gas two phase boundary in CO/CO₂ and in cathodic polarization can explain why the highest reaction rate is obtained for CO₂ electrolysis. Large differences observed between model electrode kinetics and porous electrode kinetics are discussed.

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Góral, Marek, Tadeusz Kubaszek, Marcin Kobylarz, Marcin Drajewicz und Maciej Pytel. „Thermal Barrier Coating Deposited Using the PS-PVD Method on TiAl-Nb-Mo Intermetallic Alloy with Different Types of Bond Coats“. Solid State Phenomena 320 (30.06.2021): 60–65. http://dx.doi.org/10.4028/www.scientific.net/ssp.320.60.

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TiAl intermetallics can be considered an alternative for conventional nickel superalloys in the high-temperature application. A TBC (Thermal Barrier Coatings) with ceramic topcoat with columnar structure obtained using EB-PVD (electron beam physical vapour deposition) is currently used to protect TiAl intermetallics. This article presents the new concept and technology of TBC for TiAl intermetallic alloys. Bond coats produced using the slurry method were obtained. Si and Al nanopowders (70 nm) were used for water-based slurry preparation with different composition of solid fraction: 100 wt.% of Al, 50 wt.% Al + 50 wt.% Si and pure Si. Samples of TNM-B1 (TiAl-Nb-Mo) TiAl intermetallic alloy were used as a base material. The samples were immersed in slurries and dried. The samples were heat treated in Ar atmosphere at 1000 °C for 4 h. The outer ceramic layer was produced using the new plasma spray physical vapour deposition (PS-PVD) method. The approximately 110 μm thick outer ceramic layers contained yttria-stabilised zirconium oxide. It was characterised by a columnar structure. Differences in phase composition and structures were observed in bond coats. The coatings obtained from Al-contained slurry were approximately 30 μm thick and consisted of two zones: the outer contained the TiAl3 phase and the inner zone consisted of the TiAl2 phase. The second bond coat produced from 50 wt.% Al + 50 wt.% Si slurry was characterised by a similar thickness and contained the TiAl2 phase, as well as titanium silicides. The bond coat formed from pure-Si slurry had a thickness < 10 μm and contained up to 20 at % of Si. This suggests the formation of different types of titanium silicides and Ti-Al phases. The obtained results showed that PS-PVD method can be considered as an alternative to the EB-PVD method, which is currently applied for deposition a columnar structure ceramic layer. On the other hand, the use of nanopowder for slurry production is problematic due to the smaller thickness of the produced coating in comparison with conventional micro-sized slurries.

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Peterson, R. C., und N. M. Laurendeau. „The emittance of yttrium-beryllium oxide thermocouple coating“. Combustion and Flame 60, Nr. 3 (Juni 1985): 279–84. http://dx.doi.org/10.1016/0010-2180(85)90033-1.

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Christenn, Claudia, und Syed Asif Ansar. „Constrained and Non-Constrained Sintering of Plasma-Sprayed Zirconia Based Electrolytes for SOFCs“. Advances in Science and Technology 65 (Oktober 2010): 263–68. http://dx.doi.org/10.4028/www.scientific.net/ast.65.263.

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Electrolyte layers for solid oxide fuel cells (SOFCs) consisting typically of yttria-stabilized zirconia were prepared using atmospheric plasma spraying in a first step and sintered in a second one. The influence of particle size on sintering kinetics and microstructure development was analyzed by comparison of nanostructured and conventional YSZ layers. Sintering of free-standing coatings differ significantly from that of coatings on substrates.

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Singh, A. K., T. R. G. Kutty und Sucharita Sinha. „Pulsed laser deposition of corrosion protective Yttrium Oxide (Y2O3) coating“. Journal of Nuclear Materials 420, Nr. 1-3 (Januar 2012): 374–81. http://dx.doi.org/10.1016/j.jnucmat.2011.10.028.

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Vardanyan, E. L., A. Yu Nazarov, S. N. Galyshev, R. F. Gallyamova und S. T. Mileyko. „Yttrium molybdates coating deposition of oxide-fibre/molybdenum-matrix composites“. IOP Conference Series: Materials Science and Engineering 387 (Juli 2018): 012082. http://dx.doi.org/10.1088/1757-899x/387/1/012082.

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Wu, Yunyi, Di He, Hua Zhang, Shuai Li, Xiaopeng Liu, Shumao Wang und Lijun Jiang. „Preparation of yttrium oxide coating by MOCVD as tritium permeation barrier“. Fusion Engineering and Design 90 (Januar 2015): 105–9. http://dx.doi.org/10.1016/j.fusengdes.2014.12.001.

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Yalcin, Mesut, Denizhan Ozmen und Fahrettin Yakuphanoglu. „Sr-doped yttrium nickel oxide-based photodetectors“. Journal of Materials Science: Materials in Electronics 31, Nr. 4 (13.01.2020): 3441–55. http://dx.doi.org/10.1007/s10854-020-02892-z.

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Clarke, David R. „Luminescence Sensing of Temperature in Oxides“. Key Engineering Materials 368-372 (Februar 2008): 1–4. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1.

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The measurement of temperature based on the characteristic lifetime decay in luminescence intensity of dopant ions following excitation is described with illustrations drawn from europium doping in yttria-stabilized zirconia. The method is particularly attractive for making measurements in a temperature gradient, such as those in thermal barrier coatings.

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HUANG, Manlian, Kai GUO, Zhenyong MAN, Haohong CHEN, Xinxin YANG, Fangfang XU und Jingtai ZHAO. „Morphology controllable synthesis of yttrium oxide-based phosphors from yttrium citrate precursors“. Journal of Rare Earths 29, Nr. 9 (September 2011): 830–36. http://dx.doi.org/10.1016/s1002-0721(10)60551-0.

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Almomani, Mohammed A., Mohamad I. Al-Widyan und Sulaiman M. Mohaidat. „Thermal shock resistance of yttrium aluminium oxide Y3Al5O12 thermal barrier coating for titanium alloy“. Journal of Mechanical Engineering and Sciences 14, Nr. 1 (23.03.2020): 6514–25. http://dx.doi.org/10.15282/jmes.14.1.2020.26.0511.

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The high strength-to- weight ratio of titanium alloys allows their use in jet engines. However, their use is restricted by susceptibility to oxidation at high temperatures. In this study, the possibility of increasing the operating temperature of titanium alloys through using Yttrium Aluminum Oxide (YAG) as a thermal barrier coating material for Ti-6Al-4V substrate is studied. The study concludes that YAG can be utilized to increase the operating temperature of Ti-6Al-4V titanium alloy from around 350 °C to 800 °C due to its low thermal conductivity and phase stability up to its melting point. In addition, its lower oxygen diffusivity in comparison with the standard YSZ material will provide a better protection of the titanium substrate from oxidation. In this work, coating was created using atmospheric plasma spray. X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to examine coatings' composition and structure. The coating was characterized by thermal shock test, Vickers hardness test and adhesion strength test. X-ray diffraction indicated that the coating was of a partially crystalline Y3Al5O12 composition. The coating was porous with excellent thermal shock resistance at 800 oC, with a Vickers micro-hardness of 331.35 HV and adhesion strength of 17.6 MPa.

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Saruhan, Bilge, Uwe Schulz und Marion Bartsch. „Developments in Processing of Ceramic Top Coats of EB-PVD Thermal Barrier Coatings“. Key Engineering Materials 333 (März 2007): 137–46. http://dx.doi.org/10.4028/www.scientific.net/kem.333.137.

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Partially Yttria Stabilized Zirconia (PYSZ) based Thermal Barrier Coatings (TBC) manufactured by EB-PVD process are a crucial part of a system, which protects the turbine blades situated at the high pressure sector of aero engines and stationary gas turbines under severe service conditions. These materials show a high strain tolerance relying on their unique coating morphology, which is represented by weakly bonded columns. The porosity present in ceramic top coats affects the thermal conductivity by reducing the cross sectional area through which the heat flows. The increase in thermal conductivity after heat-treatment relates to the alteration of the shape of the pores rather than the reduction of their surface-area at the cross section. The studies carried out by the authors demonstrate that the variation of the parameters during the EB-PVD processing of PYSZ based top-coats alters the columnar morphology of the coatings. Consequently, these morphological changes affect primarily the thermal conductivity and eventually the Young’ Modulus which are the key physical properties of this material group. New ceramic compositions covering zirconia coatings stabilized with alternative oxides, pyrochlores and hexaluminates are addressed. Failures occurring in ceramic top coats mark the lifetime of TBC system and therefore, it is necessary that their performance should go beyond that of the-state-of-the-art materials. This context summarizes the research and developments devoted to future generation ceramic top coats of EB-PVD TBCs.

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Avdin, Viacheslav V., Valeria V. Trunova und Aleksandra V. Bulanova. „Nanostructured Yttrium Oxide Obtained by Hydrolysis of Yttrium Sulfate“. Materials Science Forum 946 (Februar 2019): 109–14. http://dx.doi.org/10.4028/www.scientific.net/msf.946.109.

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Modern functional metal oxide materials are based upon the use of nanostructured particles. In recent years materials on the basis of yttrium oxide find ever-widening application. The properties of yttrium oxide depend heavily on precursors and synthesis conditions. One of the poorly investigated precursors is yttrium sulfate. The study discusses the products of alkaline hydrolysis of yttrium sulfate obtained by the sol-gel method. The influence of the synthesis pH on morphological, thermal and structural properties of compounds has been examined. Formation of non-stoichiometric compounds occluding counter-ions of the reactant salts in their structure has been revealed. The nanostructured hydrolysis products are formed, which increase their specific surface at annealing and retain their morphology and sizes. The obtained results give grounds to expect using yttrium sulfate as a precursor for synthesis of structured yttrium oxide.

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Cueff, Régis, C. T. Nguyen, Henri Buscail, Eric Caudron, Christophe Issartel und Frédéric Riffard. „The Effects of Reactive Element Oxide Coatings on the High Temperature Oxidation of FeCrAl Alloy“. Materials Science Forum 595-598 (September 2008): 933–40. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.933.

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The effect of reactive element additions (external doping as an yttrium-oxide coating on the metal) on the oxidation behaviour of a commercial FeCrAl alloy (Kanthal A1) has been investigated during isothermal exposures in air at 1373K. The scale growth kinetics of the bare alloy obey a parabolic rate law during the whole oxidation test whereas the kinetic curves of the yttrium-bearing specimen exhibit an initial transient stage during the first hours, followed by a parabolic regime. The yttrium addition to the bare alloy does not give the beneficial effect usually ascribed to the reactive elements. No significant oxidation rate improvement of the alloy is observed, the parabolic rate constants values obtained are roughly similar for the both specimens. In situ X-ray diffraction reveals a marked influence of the reactive element on the composition of the oxide scale. The oxide layer formed on the yttrium-bearing specimen revealed, in addition to α- alumina which is the main oxide also identified on the bare specimen, the presence of yttrium aluminates (YAlO3, Y3Al5O12) located in the outermost part of the layer.

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Kim, Hyun-Ju, Dong-Yun Lee und Jae-Sung Song. „Characterization of Yttrium Doped Zinc Oxide Thin Films Fabricated by Spin-coating Method“. Journal of the Korean Institute of Electrical and Electronic Material Engineers 19, Nr. 5 (01.05.2006): 457–60. http://dx.doi.org/10.4313/jkem.2006.19.5.457.

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Makarov, N. A., D. O. Lemeshev und K. I. Ikonnikov. „Transparent ceramic based on yttrium oxide with scandium oxide and neodymium oxide additions“. Glass and Ceramics 68, Nr. 5-6 (September 2011): 191–93. http://dx.doi.org/10.1007/s10717-011-9350-8.

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47

Choux, Céline, Sébastien Chevalier und Yannik Cadoret. „Elaboration of Nickel Aluminide Diffusion Coatings: Application to Oxidation Resistance“. Materials Science Forum 595-598 (September 2008): 41–49. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.41.

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Aluminide diffusion coatings are widely used in aeronautic domain. Nickel based superalloys present good mechanical properties and creep resistance at high temperature but their corrosion resistance is somewhat poor. In order to enhance their lifetime at high temperature, aluminide coatings can be applied on alloy surface. Aluminium present on material surface can form, at high temperature, alumina scale which is a protective oxide scale. In the present study, nickel aluminide coatings were carried out by aluminisation in a single step pack cementation process on nickel based superalloys 600 and AM1. Ni-Al intermetallic was obtained in each case. Oxidation tests were carried out at 900°C in air under atmospheric pressure. At this temperature, transient alumina as γ-Al2O3 and θ-Al2O3 appear on surface and are less protective than the stable α- Al2O3. Reactive elements can enhance α-Al2O3 nucleation and change diffusion mechanism during oxidation leading to a better adherence of alumina scale. In the present work, yttria was introduced by Metal-Organic Chemical Vapour Deposition (MOCVD) prior to the aluminisation. Yttria doped and undoped sample behaviours were compared under oxidising atmospheres.

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Abbas, Musharaf, Hasan Junaid Hasham und Yasir Baig. „Numerical Parametric Analysis of Bond Coat Thickness Effect on Residual Stresses in Zirconia-Based Thermal Barrier Coatings“. High Temperature Materials and Processes 35, Nr. 2 (01.02.2016): 201–7. http://dx.doi.org/10.1515/htmp-2014-0185.

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AbstractNumerical-based finite element investigation has been conducted to explain the effect of bond coat thickness on stress distribution in traditional and nanostructured yttria-stabilized zirconia (YSZ)-based thermal barrier coatings (TBC). Stress components have been determined to quantitatively analyze the mechanical response of both kinds of coatings under the thermal shock effect. It has been found that maximum radial tensile and compressive stresses that exist at thermally grown oxide (TGO)/bond coat interface and within TGO respectively decrease with an increase in bond coat thickness. Effect of bond coat thickness on axial tensile stresses is not significant. However, axial compressive stresses that exist at the edge of the specimen near bond coat/substrate interface decrease appreciably with the increase in bond coat thickness. Residual stress profile as a function of bond coat thickness is further explained for comparative analysis of both coatings to draw some useful conclusions helpful in failure studies of TBCs.

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Voronov, V. A., Yu E. Lebedeva, O. Yu Sorokin und M. L. Vaganova. „Structure and Properties of a High-Temperature Coating Based on Yttrium Silicate and Yttrium Aluminosilicate Precursors“. Inorganic Materials 57, Nr. 6 (Juni 2021): 603–13. http://dx.doi.org/10.1134/s002016852106011x.

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Li, Ming Sheng, Chang Jie Feng, Fu Hui Wang und Wei Tao Wu. „Long-Term Oxidation Resistance of (Ti,Al,Y)N Coatings at 800 °C“. Materials Science Forum 546-549 (Mai 2007): 1789–94. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1789.

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Composite metastable Ti0.5Al0.5N, Ti0.49Al0.49Y0.02N and Ti0.48Al0.48Y0.04N coatings were deposited on a wrought martensite steel 1Cr11Ni2W2MoV for aero-engine compressor blades by arc ion plating respectively all coatings possessed a dense surface and the same B1NaCl phase structure and the lattice parameter increased with increase of the incorporated element Y. Oxidation-resistance of (Ti,Al,Y)N coatings at 800 for up to 500 hr was investigated and the results showed that the introduction of yttrium into the coatings dramastically improved the oxidation-resistance of the coatings in air. The presence of Y in the nitride coatings suppresses the outer diffusion of Fe through the nitride coating. And the oxide of yttrium may segregate to the grain boundaries of oxides, suppressing the outward diffusion of metallic elements in coating and the inward diffusion of oxygen. Besides, the existence of adequate Y in the coatings is in favor of suppression of the growth of oxide crystals, formation layered oxide scale and decrease of compressive stress of oxidation.

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