Littérature scientifique sur le sujet « Zirconia yttria coatings »

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Articles de revues sur le sujet "Zirconia yttria coatings"

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Anderson, A. « Determination of Abrasive Wear Resistance of Plasma Sprayed Coatings on Stainless Steel Substrate ». Applied Mechanics and Materials 766-767 (juin 2015) : 579–84. http://dx.doi.org/10.4028/www.scientific.net/amm.766-767.579.

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A relative study among various types of coating materials to develop wear resistance of stainless steel has been performed. Ceramic coatings with the thickness up to 250 μm were prepared by Atmospheric plasma spray technique on the stainless steel. Two different types of coating materials such that Yttria Stabilised Zirconia, Zirconia Ceria powder were used. The influence of Ceria powder on abrasive wear was determined. It was found that the addition of Ceria to Yttria Stabilised Zirconia in a sufficient amount helped in increasing its wear resistance compared to the wear behaviour of pure Yttria Stabilised Zirconia powder. Moreover, it was found that the lesser the surface roughness of the coating layer,.
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Jech, David, Michaela Remešová, Pavel Komarov, Serhii Tkachenko, Zdeněk Česánek, Jan Schubert, Šárka Houdková et Ladislav Čelko. « Evaluation of Microstructure, Phase Composition and Hardness of Alternative Abradable Ceramic Coating Systems Produced by Means of Atmospheric Plasma Spraying ». Solid State Phenomena 296 (août 2019) : 161–66. http://dx.doi.org/10.4028/www.scientific.net/ssp.296.161.

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Only a few types of commercially available high temperature ceramic abradable coatings are presented on the market and most of them consist of partially stabilized yttria zirconia with polymer porosity former agent and/or hBN solid lubricant. The basic demand placed on abradable coatings include balance between hardness and erosion resistance. The contribution focuses on the description of microstructure, phase composition and hardness of alternative atmospheric plasma sprayed ceramic abradable coatings deposited from four different experimental powder mixtures: (i) commercial yttria-zirconia + 5 wt. % of experimental BaF2/CaF2, (ii) commercial yttria stabilized zirconia + 10 wt. % of experimental BaF2/CaF2, (iii) R&D powder SrxTiOy and (iv) R&D powder SrxTiOy + 5 wt. % of polyester. The abradable coating systems were of ~ 150 μm thick CoNiCrAlY bond coat and of ~ 800-1000 μm thick ceramic top coat. The microstructure and phase composition of all atmospheric plasma sprayed coating systems were evaluated by the means of scanning electron microscopy and X-ray diffraction techniques. To estimate coatings basic parameters the Rockwell hardness HR15Y was measured.
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Shao, Hui Liang, Xin Ying Qi et Jing Jing Song. « Microstructure and Properties of Zirconia Co-Doped with Yttria and Cenosphere Coating Prepared by Air Plasma Spraying ». Materials Science Forum 789 (avril 2014) : 513–17. http://dx.doi.org/10.4028/www.scientific.net/msf.789.513.

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Conventional yttria partially stabilized zirconia (YSZ) coating and zirconia co-doped with yttria and cenosphere (ZCYC) coating have been deposited by air plasma spraying (APS). Scanning electron microscope, energy spectrum analysis equipment were used to characterize the microstructure of the coatings. Pore structures made by cenosphere were found inside the ZCYC. It is noticed that adding 20% volume fraction of cenosphere in the YSZ poweders can reduce the density of the coating by 13.2%, compared with the conventional coating. The co-doping with yttria and cenophere improves the the corrosion resistance of the coating. The coating has good shock thermal and abrasion resistances with cenosphere.
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Marinenko, Ryna B., David S. Bright et Eric B. Steel. « A Study of An Yttria-Doped Zirconia Coating With Electron Microprobe Wavelength Dispersive Compositional Mapping ». Microscopy and Microanalysis 3, S2 (août 1997) : 897–98. http://dx.doi.org/10.1017/s1431927600011375.

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Yttria-doped zirconia plasma-sprayed thermal barrier coatings (TBC’s) have been used successfully to improve the performance and extend the life of industrial equipment such as jet engines. For this reason, there is considerable interest in understanding and improving the plasma spray process and resulting TBC’s. A collaborative research program exists between Sandia National Laboratories and the National Institute of Science and Technology (NIST) to study the materials and processes used in preparing the coatings as well as the relationship between the physical properties of the coating and its microstructure.The purpose of this work was to determine the elemental compositions on a micrometer scale of an yttria-doped zirconia coating. The cubic and tetragonal crystal forms of the yttria-doped zirconia have the most favorable thermal expansion coefficient, therefore providing the most effective thermal barrier. The Y concentration in these crystal phases is known to be 6-7 wt%, while the less desirable monoclinic phase, having a less favorable thermal expansion coefficient, contains less that 3 wt% Y.
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Pinto, M. A., W. R. Osório, C. R. P., A. García et M. C. F. Ierardi. « Laser surface treatment of plasma-sprayed yttria-stabilized zirconia coatings ». Revista de Metalurgia 41, Extra (17 décembre 2005) : 154–59. http://dx.doi.org/10.3989/revmetalm.2005.v41.iextra.1016.

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Savushkina, Svetlana, Mikhail Gerasimov, Andrey Apelfeld et Igor Suminov. « Study of Coatings Formed on Zirconium Alloy by Plasma Electrolytic Oxidation in Electrolyte with Submicron Yttria Powder Additives ». Metals 11, no 9 (1 septembre 2021) : 1392. http://dx.doi.org/10.3390/met11091392.

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Coatings with thickness 40 to 150 μm were formed by plasma electrolytic oxidation (PEO) on the zirconium alloy Zr-1Nb (Zr-1% Nb) in the slurry electrolyte containing 9 g/L Na2SiO3 5H2O, 5 g/L Na(PH2O2) and 6 g/L submicron Y2O3 yttria powder during 60 min under the AC electrical mode at current densities 20; 30 and 40 A/dm2. The surface morphology, structure, composition, and corrosion-protective ability of the formed coatings have been analyzed. At PEO current density 30 A/dm2, a predominantly tetragonal phase of zirconia was formed in coatings. Increasing the PEO current density up to 40 A/dm2 promoted the formation of the coating surface layer containing submicron yttria particles. Electrochemical polarization studies in 0.5% LiOH solution showed that PEO coatings demonstrated high corrosion-protective ability. The dependence of the polarization currents on the PEO current density was found to be inconsequential.
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Habeeb, Mais A., Mohammed J. Kadhim, Fadhil A. Hashim et Maryam A. Bash. « Effect of Laser Treatment on the Surface Roughness of Multilayer Plasma Sprayed Thermal Barrier Coating System ». Engineering and Technology Journal 39, no 2A (25 février 2021) : 180–88. http://dx.doi.org/10.30684/etj.v39i2a.1570.

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Thermal barrier coatings (TBCs) are used in advanced engines working at higher temperatures. Higher efficiency and performance of gas turbine engines will require careful selection of TBCs. In this study, Ni22Cr10Al1.0Y (Amdry 9625) bond coat and two types of top coat including ceria stabilized zirconia (CSZ) ZrO2-24CeO2-2.5Y2O3) and yttria stabilized zirconia (YSZ) ZrO2-8Y2O3 were deposited on IN 625 by air plasma spraying (APS). The thickness of the duplex ceramic coat based on zirconia was in the range between 350 to 400 µm. The effect of high power Yb:YAG solid state laser at different laser parameters on feature, microstructure and roughness of plasma sprayed and laser sealed coating of multilayer ceria stabilized zirconia/ yttria stabilized zirconia was investigated. Surface roughness has been reduced significantly after laser sealing. The effect of laser process parameters carried out using Taguchi’s L16 orthogonal array design. Minimum roughness can be obtained at moderate power density and longer interaction time with sufficient specific energy to produce complete melting of coating. Characterization and analysis of results was achieved by employing scanning electron microscopy (SEM) , (EDS) and image J analysis. It was found from the results, there were significant improvements in the performance of plasma sprayed coatings after laser sealing due to the reduction of surface coating defects.
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Solodovnikov, Sergey, Igor Igumenov, Roman Shutilov et Vladimir Lukashov. « Functional coatings made of eco-friendly materials ». E3S Web of Conferences 459 (2023) : 09002. http://dx.doi.org/10.1051/e3sconf/202345909002.

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Thermal barrier coatings protect alloys (for example, in turbine blades) from extreme temperatures. There is a pressing need to find better materials than currently used yttria-stabilized zirconia (i.e. materials with better thermal stability, lower thermal conductivity, higher thermal expansion coefficient matching that of the alloy). Here we explore gehlenite (Ca2Al2SiO7) for possible application as a material for thermal barrier coatings. We found that gehlenite can indeed be used in next-generation thermal barrier coatings, as a top coat on a thin layer of yttria-stabilized zirconia.
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Wang, De Ren. « Alumina and Zirconia Laminar Coating Prepared by Complex Electrolytic Deposition Method ». Advanced Materials Research 538-541 (juin 2012) : 391–96. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.391.

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The deposition of alumina (nano-powder, <80nm) and zirconia doped with yttria laminar composite coatings on Ni3Al coatings were investigated via a complex method of Sol-Gel, electrolytic deposition (ELD) and electrophoretic deposition (EPD). The average particle sizes of alumina and zirconia are 80nm and 20nm respectively. The relation of deposition parameters (deposition voltage, dwell time) and deposition rate was discussed based on the experiment results of alumina, zirconia single and laminated coatings deposition. The post thermal treatments were performed in attempt to acquire a dense multilayer composite ceramic coating. The uniform duplex or laminar coatings could be achieved via this complex method. The surface and cross-sectional morphologies of two layers and ten layers alumina/ zirconia composite ceramic coating after sintering showed that the laminar structure thickness could be tailored by controlling the deposition voltage and dwell time. The sintering mechanism of nano-sized alumina and zirconia was also discussed.
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Thibblin, Anders, Siamak Kianzad, Stefan Jonsson et Ulf Olofsson. « Running-in behaviour of thermal barrier coatings in the combustion chamber of a diesel engine ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 234, no 1 (10 avril 2019) : 172–82. http://dx.doi.org/10.1177/0954407019841173.

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Thermal barrier coatings have the potential to improve the fuel efficiency of heavy-duty diesel engines by reducing heat losses. A method for in-situ measurement of heat flux from the combustion chamber of a heavy-duty diesel engine has been developed and was used to study the running-in behaviour of different thermal barrier coating materials and types of microstructures. The in-situ measurements show that the initial heat flux was reduced by up to 4.7% for all investigated thermal barrier coatings compared to a steel reference, except for an yttria-stabilized zirconia coating with sealed pores that had an increase of 12.0% in heat flux. Gd2Zr2O7 had the lowest initial value for heat flux. However, running-in shows the lowest values for yttria-stabilized zirconia after 2–3 h. Potential spallation problems were observed for Gd2Zr2O7 and La2Zr2O7.
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Thèses sur le sujet "Zirconia yttria coatings"

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Ji, Changzheng. « Fabrication of yttria-satbilised-zirconia coatings using electrophoretic deposition ». Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489513.

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Yttria-stabilized-zirconia (YSZ) coatings have been fabricated on metallic (Fecralloy) substrates using a colloidal processing technique, namely electrophoretic deposition (EPD). The deposition of YSZ particles has been examined as a function of EPD conditions and suspension properties.
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Xu, Hui. « Fabrication of yttria-stabilized-zirconia (YSZ) coatings by electrophoretic deposition (EPD) ». Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/fabrication-of-yttriastabilizedzirconia-ysz-coatings-by-electrophoretic-deposition-epd(db294fcd-90d1-459a-939c-c6a9c13e5e9f).html.

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Yttria stabilized zirconia (YSZ) coatings were produced from a YSZ suspension in acetylacetone (ACAC) using electrophoretic deposition (EPD) and then consolidated via the natural drying and isothermal sintering with the constraint of the metal substrates. Before EPD, the operational pH of the suspension was adjusted by addition of acetic acid or organic bases. The effect of suspension pH on the deposition of EPD coatings was studied with respect to the suspension stability, coating density and microstructure both for a mono-sized system and micro-nano binary systems. The constrained drying process of the deposits was examined via the measurement of the critical cracking thickness (CCT). The sinterability of coatings was evaluated by micro-hardness and microstructure. For a mono-sized (0.26μm) suspension, results showed that the zeta potential had a high positive value on both sides of the isoelectric point (IEP). This probably resulted from the adsorption of base molecules triethanolamine (TEA), detected by fourier transform infrared spectroscopy. Three alkalis with different molecular structure were compared and the effect of their molecule length on the interparticle repulsion was discussed. Accordingly, the double layer thickness of the particles can be estimated. Based on this, particle interactions were estimated for different pH suspensions. The reduced particle coagulation increased the packing density of the EPD coatings from 38 % at pH 7.4 to 53 % at pH 8.4. Therefore, subsequent sintering of coatings was promoted. After sintering at 1200 °C, coatings made in pH 8.4 suspensions obtained a much higher hardness and had fewer big pores than coatings fabricated in pH 7.4 suspensions. The CCT of the latter is slightly higher than the former which might be ascribed to its particle network structure. In a binary suspension composed of the coarse (1μm) and fine (with average size of 100 nm or 10 nm, content varied in 0-30 wt. % to the powder mixture) YSZ powders, interactions between different species can be tuned by the zeta potential of individual component. Binary particles can be well dispersed at pH 4 when both of the coarse and fine powders reached their highest zeta potentials. Heterocoagulation occurred between them to form a haloing structure with fine powders covered on the coarse particle surfaces when they exhibited zeta potentials of the opposite sign at pH 8.6. Particle interactions were estimated and the microstructures of the binary coatings were examined to discuss how the different fine particle sizes influenced the particle packing after EPD. At pH 4, there existed a “stability window” for the 10 nm fines at 10 wt. % whereas no noticeable the border of the window can be observed for 100 nm fines within the measuring range. 10 nm and 100 nm fine powders gave similar overall densities of binary EPD coatings which were independent of the fine powder content. For heterocoagulation coatings made at pH 8.6, although the adsorption of fine particles reduce the agglomeration of coarse powder, the low zeta potential of the halos led to a loose structure of the “skeleton” ( the packing of the coarse powder) in the final binary coatings. 10 nm fine powders was observed to give a higher CCT and denser particle packing than 100 nm fine powders especially in a pre-saturated heterocoagulated binary coatings at 20 wt. % fine powder content. In order to further improve the sintering of the EPD coatings at low temperature sintering, a layer of CuO was applied on the coarse powder surface. With the addition of 30 wt. % fine powders, the hardness of EPD coatings after sintering 2 hours at 1150°C increased from 6 to 61 Vickers. With the presence of CuO, the hardness values were enhanced by 2.5-4.25 times. The density measurements indicated that the CuO layer not only served as a sintering aid, the CuO layer also helped with the binary particle packing particularly in the heterocoagulation condition because of the stronger particle interactions between the fine powders and CuO modified coarse powders. It seems that CuO had no significant impact on the cracking resistance of the binary coatings during drying, however t-m phase transformation was observed during sintering possibly due to the liquid phase induce by CuO.
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Askestad, Inga. « Ceramic Thermal Barrier Coatings of Yttria Stabilized Zirconia Made by Spray Pyrolysis ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16324.

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A thermal barrier coating (TBC) is used as thermal protection of metallic components exposed to hot gas streams in e.g. gas turbine engines. Due to a high thermal expansion coefficient, low thermal conductivity, chemical- and thermal stability, yttria stabilized zirconia (YSZ) is the most widely used material for TBCs today. In the work presented in this master thesis an aqueous nitrate precursor solution was prepared and deposited on stainless steel substrates by spray pyrolysis to produce 8YSZ coatings (8 mol% of Y2O3 in ZrO2). The precursor solution concentration and deposition parameters, including set-point temperature and volume sprayed, were optimized to produce continuous and crack-free green coatings.The deposited green coatings were characterized by scanning electron microscopy, thermogravimetry and Fourier transform infrared spectroscopy to study the influence of substrate temperature on the microstructure of the green coatings. A substantial change in microstructure was observed for the green coatings in a certain temperature range indicating that a minimum deposition temperature was necessary to obtain crack-free green coatings.Heat treatment was necessary to decompose the nitrate species in the deposited film. During heat treatment, vertical cracks were introduced into the coatings due to the nitrate decomposition. The cracking behavior of the coatings was studied for different drying times and conditions, and it was found that the crack propagation can be controlled to obtain the preferred size and geometry of the cracks. Due to built-up stresses in the coating, which can exceed the fracture toughness of the material, it was found that there was a maximum film thickness achievable before spallation of the coating for a given precursor solution. Therefore, the possibility of spraying multi-layered coatings was investigated. The introduction of a second layer showed that it was possible to double the thickness of the coating.
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Guo, Fangwei. « Electrophoretic deposition of yttria-stabilized zirconia for application in thermal barrier coatings ». Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/electrophoretic-deposition-of-yttriastabilized-zirconia-for-application-in-thermal-barrier-coatings(05f66a54-9ab3-4d18-8378-6e02a3895dfc).html.

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Electrophoretic deposition (EPD) has been used to produce the yttria-stabilized zirconia (YSZ) coatings on metal substrates. Sintering of YSZ with and without doping has been carried out at 1150 °C for 2hrs. The properties of these coatings have been examined in light of thermal barrier applications. For EPD, the green density increases with an initial increase in the HCl concentration and the EPD time. This suggests that particle packing was influenced by a time dependent re-arrangement, in addition to the initial suspension dispersion state. The green density peaks at a electrical conductivity of around 10×10-4 S/m achieved by an 0.5 mM HCl addition for the 20 g/l suspensions with the EPD time of around 8 ~10 minute. For sintered coatings, the HCl concentration had a marked effect on the neck size to grain size ratio of the 8 mol% yttria-stabilized zirconia (8YSZ) coatings. The presence of ZrCl4 and ZrOCl2, and a high concentration of oxygen vacancies at the grain boundaries are believed to promote neck growth in the early stage of sintering at 1150 °C. During sintering of 3 mol% and 8 mol% yttria-stabilized zirconia (3YSZ and 8YSZ) at 1150 ºC for 2hrs, the densification rate substantially increased with a small amount of Fe2O3 addition (0.5 mol%) to the 3YSZ/8YSZ deposits. A more pronounced graingrowth was present in the Fe2O3 doped 8YSZ deposits. The increased Zr4+ diffusion coefficient is mainly responsible to the rapid densification rate of the Fe2O3 doped 3YSZ/8YSZ deposits. A small grain growth observed in the Fe2O3 doped 3YSZ deposits is attributed to the Fe3+ segregation at grain boundary. A small amount of CeO2 doping was found to substantially inhibit the densification rate of the doped 3YSZ deposits with a minor grain growth. Fe2O3 doping reduced the thermal conductivities of 3YSZ/8YSZ. It is found that Rayleigh-type phonon scattering due to the mass difference alone is inadequate to explain the thermal conductivity of Fe2O3 doped YSZ systems. The lattice strain effects due to the ionic radius difference could more effectively reduce thermal conductivity of the Fe2O3-doped 3YSZ. A decrease in the growth rate of the TGO scale with the increasing Fe2O3 additions was observed for the oxidized FeCrAlY metal substrates with the Fe2O3-doped 3YSZ coating, which was found to be attributed to the early formation of the stable and dense α-Al2O3 phase due to the presence of Fe3+ ions.
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Rashkova, Boryana. « Microstructural characterization of yttria-stabilized zirconia thermal barrier coatings grown on sapphire substrates ». [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11293362.

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Hobbs, Martin K. « The structure and properties of plasma-sprayed 8% yttria-zirconia thermal barrier coatings ». Thesis, University of Bath, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234081.

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Mahade, Satyapal. « Functional Performance of Gadolinium Zirconate/Yttria Stabilized Zirconia Multi-Layered Thermal Barrier Coatings ». Licentiate thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-9854.

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Yttria stabilized zirconia (YSZ) is the state of the art ceramic top coat material used for TBC applications. The desire to achieve a higher engine efficiency of agas turbine engine by increasing the turbine inlet temperature has pushed YSZ toits upper limit. Above 1200°C, issues such as poor phase stability, high sinteringrates, and susceptibility to CMAS (calcium magnesium alumino silicates) degradation have been reported for YSZ based TBCs. Among the new materials,gadolinium zirconate (GZ) is an interesting alternative since it has shown attractive properties including resistance to CMAS attack. However, GZ has a poor thermo-chemical compatibility with the thermally grown oxide leading to poor thermal cyclic performance of GZ TBCs and that is why a multi-layered coating design seems feasible.This work presents a new approach of depositing GZ/YSZ multi-layered TBCs by the suspension plasma spray (SPS) process. Single layer YSZ TBCs were also deposited by SPS and used as a reference.The primary aim of the work was to compare the thermal conductivity and thermal cyclic life of the two coating designs. Thermal diffusivity of the YSZ single layer and GZ based multi-layered TBCs was measured using laser flash analysis (LFA). Thermal cyclic life of as sprayed coatings was evaluated at 1100°C, 1200°C and 1300°C respectively. It was shown that GZ based multi-layered TBCs had a lower thermal conductivity and higher thermal cyclic life compared to the single layer YSZ at all test temperatures. The second aim was to investigate the isothermal oxidation behaviour and erosion resistance of the two coating designs. The as sprayed TBCs were subjected toisothermal oxidation test at 1150°C. The GZ based multi-layered TBCs showed a lower weight gain than the single layer YSZ TBC. However, in the erosion test,the GZ based TBCs showed lower erosion resistance compared to the YSZ singlelayer TBC. In this work, it was shown that SPS is a promising production technique and that GZ is a promising material for TBCs.
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Wang, Steven Yuan Jun. « Thermal conductivity and sintering characteristics of plasma sprayed dysprosia-yttria-zirconia thermal barrier coatings ». Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/7379.

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Yttria-stabilized zirconia has long been the favoured refractory material for demanding applications such as thermal barrier coatings on turbine components. Its low thermal conductivity, relatively high thermal expansion coefficient, and good fracture toughness are most useful parameters when acute thermal cycles are considered. In recent years however, the demand for higher turbine operating temperatures has led to novel and innovative research in improving the thermal conductivity and sintering resistance of thermal barrier coatings. Rareearth doped zirconia, rare-earth zirconates, and lanthanum hexa-aluminate have all been proposed as candidate materials for the next generation of thermal barrier coatings. Drawn from research conducted during 2003-2005, this study focuses on dysprosia as a ternary dopant to yttria-stabilized zirconia, examining the relationship of dopant content with overall thermal conductivity and sintering behaviour under cyclic thermal loading between room temperature and 1100°C. Air plasma spray deposition technique was employed for coatings deposition. Based on existing published works, this study is prefaced with four hypotheses: 1. increasing levels of dysprosia would likely result in lower overall thermal conductivity; 2. best improvement occurs at about 10 mol% total dopant (Dy + Y); 3. addition of dysprosia is also likely to increase sintering resistance during thermal cycling, since Dy cation radius is larger than Zr; 4. higher dopant concentrations, between 10 mol% and 50 mol%, should increasingly lead to shorter coating life under thermal cycling. As-sprayed coating heat capacity, thermal diffusivity, and porosity were measured by differential scanning calorimetry, laser flash method, and image analyses, respectively. Post-cycle coating porosity levels were compared against data for as-sprayed coatings. A theoretical model for estimating the thermal conductivity of plasma sprayed zirconia coatings was derived and constructed from previous works by other researchers. Experimental data and theoretical model presented in this study offer positive confirmations for the hypotheses, with the exceptions that the greatest reduction in thermal conductivity was seen at 15 mol% total dopant and that increased levels of dysprosia did not result in continued reductions in thermal conductivity. Literature data suggests long range ordering of oxygen vacancies could be a contributing factor in this trend.
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Kondos, Konstandinos G. « X-ray diffraction and electron microscope studies of yttria stabilzed zirconia (YSZ) ceramic coatings exposed to vanadia ». Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23814.

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Gupta, Mohit. « Establishment of Relationships between Coating Microstructure and Thermal Conductivity in Thermal Barrier Coatings by Finite Element Modelling ». Thesis, Högskolan Väst, Institutionen för ingenjörsvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-3247.

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Plasma sprayed Thermal Barrier Coating systems (TBCs) are commonly used for thermal protection of components in modern gas turbine application such as power generation, marine and aero engines. The material that is most commonly used in these applications is Yttria Partially Stabilized Zirconia (YPSZ) because of this ceramic’s favourable properties, such as low thermal conductivity, phase stability to high temperature, and good erosion resistance. The coating microstructures in YPSZ coatings are highly heterogeneous, consisting of defects such as pores and cracks of different sizes which determine the coating’s final thermal and mechanical properties, and the service lives of the coatings. Determination of quantitative microstructure–property correlations is of great interest as experimental procedures are time consuming and expensive. Significant attention has been given to this field, especially in last fifteen years. The usual approach for modelling was to describe various microstructural features in some way, so as to determine their influence on the overall thermal conductivity of the coating. As the analytical models over-simplified the description of the defects, various numerical models were developed which incorporated real microstructure images.This thesis work describes two modelling approaches to further investigate the relationships between microstructure and thermal conductivity of TBCs. The first modelling approach uses a combination of a statistical model and a finite element model which could be used to evaluate and verify the relationship between microstructural defects and thermal conductivity. The second modelling approach uses the same finite element model along with a coating morphology generator, and can be used to design low thermal conductivity TBCs. A tentative verification of both the approaches has been done in this work.
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Livres sur le sujet "Zirconia yttria coatings"

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Miller, Robert A. Characterization and durability testing of plasma-sprayed zirconia-yttria and hafnia-yttria thermal barrier coatings. Part II. Effect of spray parameters on the performance of several hafnia-yttria and zirconia-yttria coatings. Cleveland, Ohio : Lewis Research Center, 1993.

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Miller, Robert A. Characterization and durability testing of plasma-sprayed zirconia-yttria and hafnia-yttria thermal barrier coatings. [Washington, DC] : National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1993.

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A, Miller Robert. Characterization and durability testing of plasma-sprayed zirconia-yttria and hafnia-yttria thermal barrier coatings. [Washington, DC] : National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1993.

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A, Miller Robert. Characterization and durability testing of plasma-sprayed zirconia-yttria and hafnia-yttria thermal barrier coatings. [Washington, DC] : National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1993.

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A, Miller Robert. Characterization and durability testing of plasma-sprayed zirconia-yttria and hafnia-yttria thermal barrier coatings. [Washington, DC] : National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1993.

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Albrecht, Cornelia D. An investigation of plasma sprayed fully yttria stabilized zirconia in thick thermal barrier coatings. Manchester : UMIST, 1997.

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Wet, D. J. De. Corrosion mechanisms of zirconia-yttria thermal barrier coatings in the presence of molten silicate debris. Manchester : UMIST, 1995.

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Miller, Robert A. Characterization and durability testing of plasma-sprayed zirconia-yttria and hafnia-yttria thermal barrier coatings. Part 1-Effect of spray parameters on the performance of several lots of partially stabilized zirconia-yttria powder. Cleveland, Ohio : Lewis Research Center, 1993.

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Kondos, Konstandinos G. X-ray diffraction and electron microscope studies of yttria stabilzed zirconia (YSZ) ceramic coatings exposed to vanadia. Monterey, Calif : Naval Postgraduate School, 1992.

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Krestos, Dean M. An X-ray diffraction investigation of *-A10 addition to yttria stabilized zirconia (YSZ) thermal barrier coatings subject to destabilizing vanadium pentoxide (V0*) exposure. Monterey, Calif : Naval Postgraduate School, 1993.

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Chapitres de livres sur le sujet "Zirconia yttria coatings"

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Xu, P., J. Mostaghimi, T. W. Coyle et L. Pershin. « Suspension Plasma Spray of Yttria Stabilized Zirconia Coatings ». Dans Ceramic Transactions Series, 451–64. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119407270.ch42.

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Stollberg, D. W., J. M. Hampikian, M. McIntosh et W. B. Carter. « Yttria Stabilized Zirconia/Alumina Coatings Deposited by Combustion Chemical Vapor Deposition ». Dans Elevated Temperature Coatings, 277–89. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118787694.ch21.

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Witz, G., V. Shklover, W. Steurer, S. Bachegowda et H. P. Bossmann. « Monitoring the Phase Evolution of Yttria Stabilized Zirconia in Thermal Barrier Coatings Using the Rietveld Method ». Dans Advanced Ceramic Coatings and Interfaces II, 39–51. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2009. http://dx.doi.org/10.1002/9780470339510.ch5.

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Boddapati, Srinivasa Rao, et Rajendra K. Bordia. « Effect of Withdrawal Speed on Thickness and Microstructure of 8MOL% Yttria Stabilized Zirconia Coatings on Inorganic Substrates ». Dans Advanced Ceramic Coatings and Interfaces II, 243–52. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2009. http://dx.doi.org/10.1002/9780470339510.ch24.

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Figueras, A., G. Garcia, J. Casado et J. Llibre. « Influence of the Experimental Parameters of Preparation on the Properties of Yttria-Stabilized Zirconia Films Deposited by Metal Organic Chemical Vapour Deposition ». Dans Protective Coatings and Thin Films, 77–87. Dordrecht : Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5644-8_7.

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Tan, Liuxi, Lei Zhao, Shengmin Guo, Ebrahim Khosravi et Shizhong Yang. « Properties of Zirconia Gadolinia Ytterbia Yttria Thermal Barrier Coating Studied by First Principles Simulation ». Dans TMS2013 Supplemental Proceedings, 335–42. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118663547.ch42.

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Deshpande-Purohit, Pritee, Shashikant Vagge et Bhavana Shrigadi. « Cyclic Oxidation of Combined LTA/YSZ and Alumina Thermal Spray Coatings ». Dans Advanced Surface Coating Techniques for Modern Industrial Applications, 71–87. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4870-7.ch003.

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Thermal barrier coatings protect the substrate from thermal diffusion, oxidation, phase transformations, elastic deformation, plastic deformation, creep deformation, thermal expansion, thermal radiation. It allows parts and components of gas turbines to withstand high temperature upto1650 °C. Cylic oxidation behavior of alumina incorporated, lanthanum titanium aluminum oxide (LaTi2Al9O19), and yttria stabilized zirconia (YSZ), that is LTA/YSZ top ceramic layer coating, was investigated. Two coating combinations, L 100 having top LTA layer thickness of 100 µm and L 150 having top layer of LTA having thickness 150 µm, were tested for thermal cycles at the temperature of 1100°C. The performances of these coatings were compared with conventional YSZ coatings. Microstructure studies, EDX, and XRD analysis demonstrated the formation of mainly LTA, LaAlO3, Al2TiO5, Al2O3, and TiO2 at 1100°C in both coatings. But in L 150 coating, the rate of oxidation was found slower than L 100 coating. Annealed L 150A and L 100A specimens show cyclic oxidation life of 272th and 250th cycles, respectively.
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Purohit, Pritee, et Shashikant Tukaram Vagge. « Oxidation and Tribology of Al2O3-Induced LaTi2Al9O19/YSZ Double Ceramic Layer Coatings ». Dans Handbook of Research on Tribology in Coatings and Surface Treatment, 45–63. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-9683-8.ch003.

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In the present work, the alumina-induced thermal barrier coatings with LaTi2Al9O19 (LTA) and yttria-stabilized zirconia (YSZ), LTA/YSZ double ceramic layer (DCL) are studied for oxidation and wear tests. Different coatings combinations with varying thickness of LaTi2Al9O19 (LTA) top coat layer are developed using plasma spray method and are tested for isothermal oxidation and wear test. An Alumina layer is induced after the bond coat layer to provide a readily available oxide layer. The activation energy is calculated using the Arrhenius equation. Arrhenius plots are developed using oxidation kinetics. Coatings are tested for wear performance also. The coating combination with a higher thickness of LTA proved best for both oxidation and wear performances. Surface characterization is done using EDS and XRD analysis.
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Cañas, Eugeni, Rut Benavente, Amparo Borrell et Ma Dolores Salvador. « Deposition of Advanced Ceramic Coatings by Thermal Spraying ». Dans Ceramic Materials - Present and Future [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.1002921.

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Advanced ceramic coatings have been largely used in several industrial fields such as aerospace, automotive, power generation, medical or petrochemical, in order to protect or functionalise the surface of different materials. In modern industries, thermal spray processes are the most used ones to manufacture advanced ceramic coatings due to their cost advantages, flexibility and efficiency in processing ceramic materials, especially those with high melting temperature. This chapter provides a brief overview of the progress and current state of different thermal sprayed ceramics and summarises the future trend in this field. Therefore, various advanced ceramics, such as yttria-stabilised zirconia, alumina, hydroxyapatite and bioactive glasses, have been selected for analysis and discussion.
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Chatterjee, Dilip, Debasis Majumdar et Syamal Ghosh. « Surface modification and wear characteristics of yttria-doped zirconia ». Dans Metallurgical Coatings and Thin Films 1992, 516–20. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89900-2.50092-0.

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Actes de conférences sur le sujet "Zirconia yttria coatings"

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Suzuki, M., S. Sodeoka et T. Inoue. « Zircon-Based Ceramics Composite Coating for Environmental Barrier Coating ». Dans ITSC2007, sous la direction de B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima et G. Montavon. ASM International, 2007. http://dx.doi.org/10.31399/asm.cp.itsc2007p0523.

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Abstract Studies on plasma spraying of zircon (ZrSiO4) have been carried out by the authors as one of the candidates for an environmental barrier coating (EBC) application, and had reported that substrate temperature is one of the most important factors to obtain crack-free and highly-adhesive coating. In this study, several amount of yttria were added to zircon powder, and the effect of the yttria addition on the structure and properties of the coatings were evaluated in order to improve the stability of the zircon coating structure at elevated temperature. The coatings obtained were composed of yttria stabilized zirconia (YSZ), glassy silica, while the one prepared from monolithic zircon powder composed of the metastable high temperature tetragonal phase of zirconia and glassy silica. After the heat treatment over 1473K, silica and zirconia formed zircon in all the coatings. However, the coatings with the higher amount of yttria had less amount of zircon formed. This resulted in the less open porosity of the coating at elevated temperature. These yttria added coatings also showed good adhesion even after the heat treatment, while monolithic zircon coating had pealed off.
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Xu, P., L. Pershin, T. W. Coyle et J. Mostaghimi. « Vacuum Plasma Spray of Yttria Stabilized Zirconia Coatings ». Dans ITSC 2016, sous la direction de A. Agarwal, G. Bolelli, A. Concustell, Y. C. Lau, A. McDonald, F. L. Toma, E. Turunen et C. A. Widener. DVS Media GmbH, 2016. http://dx.doi.org/10.31399/asm.cp.itsc2016p1132.

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Abstract In this study, zirconia coatings were fabricated by vacuum plasma spraying using hollow spherical and fused and crushed YSZ powders. Relationships between spray parameters and in-flight particle velocities and temperatures were investigated in real time and correlated with coating microstructure and density obtained under vacuum as well as atmospheric spraying conditions. The results indicate that plasma sprayed particles reach higher velocities under vacuum and slightly higher temperatures in atmospheric conditions. Powder morphology and structure play a major role in determining coating microstructure and porosity, especially in vacuum spraying. The fused and crushed powder yielded the densest coatings under the vacuum process conditions employed.
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Bouyer, E., David W. Branston, Gunter Lins, Matthias Muller, J. Verleger et M. von Bradke. « DEPOSITION OF YTTRIA-STABILISED ZIRCONIA COATINGS USING LIQUID PRECURSORS ». Dans Progress in Plasma Processing of Materials, 2001. Connecticut : Begellhouse, 2023. http://dx.doi.org/10.1615/itppc-2000.650.

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Debout, V., A. Vardelle, P. Abélard, P. Fauchais, E. Meillot, E. Bruneton, S. Schelz et N. Branland. « Optical Properties of Yttria-Stabilized Zirconia Plasma-Sprayed Coatings ». Dans ITSC2006, sous la direction de B. R. Marple, M. M. Hyland, Y. C. Lau, R. S. Lima et J. Voyer. ASM International, 2006. http://dx.doi.org/10.31399/asm.cp.itsc2006p0525.

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Abstract The objective of this study is to establish relationships between the optical properties of yttria-stabilized zirconia (YSZ) plasma-sprayed coatings and their microstructure to improve YSZ thermal barriers. So, coatings with significant microstructural differences were manufactured and their hemispherical reflectance and transmittance were investigated over the 0.25-20µm wavelength range. However as plasma-sprayed coatings are heterogeneous materials, they exhibit optical properties different from those of homogeneous ones. Indeed, the pores and grain boundaries act as scattering centers and cause modifications in optical properties that are closely linked both to intrinsic properties of materials and microstructural characteristics. Therefore, the extinction coefficient which describes the decrease in light intensity due to the light absorption and diffusion processes in the matter, was determined by using the Kubelka-Munk two-flux model. The absorption and diffusion coefficients were infered from the comparison between the experimental data and model predictions of reflectance and transmittance.
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Tao, Shunyan, Bo Liang, Chuanxian Ding, Hanlin Liao et Christian Coddet. « Wear Characteristics of Plasma Sprayed Nanostructured Yttria Partially Stabilized Zirconia Coatings ». Dans ITSC2004, sous la direction de Basil R. Marple et Christian Moreau. ASM International, 2004. http://dx.doi.org/10.31399/asm.cp.itsc2004p0872.

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Abstract Reconstituted nanostructured and conventional yttria partially stabilized zirconia (YPSZ) coatings were deposited by atmospheric plasma spray. The tribological properties of the coatings against 100C6 steel were evaluated with a ball-on-disc configuration under dry friction conditions at room temperature. Microstructure and the phase composition of the powders and the coatings were examined using SEM, optical microscope (OM) and X-ray diffraction (XRD). Microhardness, Young’s modulus and fracture toughness of coatings were measured by indentation test. Results showed that the wear resistance of the coatings produced using the nanostructured powder is improved compared with the coating produced using the conventional powder. The wear rates of nanostructured zirconia coatings are about four-fifths of those of conventional counterparts under a load of 5 N. The wear mechanism is also discussed.
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Wu, Y., Z. Li, D. He, Q. Zhao, H. Li et H. Li. « Bioactivity of Micro-Plasma Sprayed Yttria Stabilized Zirconia Coating ». Dans ITSC2008, sous la direction de B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima et G. Montavon. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2008. http://dx.doi.org/10.31399/asm.cp.itsc2008p1013.

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Abstract Yttria-stabilized zirconia coatings were deposited onto a Ti-6Al-4V substrate through a microplasma spray technique and incubated in simulated body fluid (SBF) for different periods of time (3, 7, 14, 28 days). The formation of apatite on the surface was investigated to evaluate the bioactivity of the coatings. Surface morphologies and structural changes in the coatings before and after immersion were analyzed by optical microscopy, scanning electron microscopy, and x-ray diffractometry. The calcium (Ca2+) concentration in the solutions was measured directly after the samples were removed, using an inductively coupled plasma atomic emission spectrometer (ICP). The results showed that yttria-stabilized zirconia coatings can be produced by microplasma spraying and, even though the coatings contain few small unmelted particles, apatite can be formed on the coatings that are soaked in SBF solution. These results indicate that the yttria-stabilized zirconia coatings exhibited definite bioactivity.
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Xing, Y. Z., C. J. Li, C. X. Li, H. L. Wu, R. T. Li et Q. Zhang. « Influence of Microstructure on Ionic Conductivity of Plasma-Sprayed Yttria-Stabilized Zirconia Coatings ». Dans ITSC2008, sous la direction de B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima et G. Montavon. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2008. http://dx.doi.org/10.31399/asm.cp.itsc2008p1406.

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Abstract During plasma spraying, high substrate temperature contributes to increase the interface temperature between flattening droplet and substrate and subsequently promotes the through-lamella grain growth in the coating. In this study, yttria stabilized zirconia (YSZ) coatings are prepared by atmospheric plasma spray (APS) on the stainless steel substrate preheated to different temperatures from room temperature to 1100°C. The microstructure of the coatings is characterized from polished and fractured cross sections by SEM. The ionic conductivities of the coatings are measured using both DC and AC methods, and the relationship between ionic conductivity and microstructure of coatings is examined. SEM observation shows that the coatings exhibit different microstructures with different substrate temperatures. With the increase of substrate temperature, the columnar grain growth continuously across lamellar interfaces is enhanced and subsequently the intersplat bonding ratio in the coating is increased. The ionic conductivity of YSZ coatings at the direction perpendicular to coating surface is significantly increased through the microstructure development by increasing deposition temperature.
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Mailhot, K., F. Gitzhofer et M. I. Boulos. « Supersonic Induction Plasma Spraying of Yttria Stabilised Zirconia Films ». Dans ITSC 1998, sous la direction de Christian Coddet. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.itsc1998p1419.

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Abstract In this paper, supersonic RF induction plasma deposition of Yttria Stabilized Zirconia (YSZ) has been developed in order to produce dense solid electrolyte membranes for Solid Oxide Fuel Cells (SOFC). Different RF induction plasma torch configurations were tested. The results show that high density layers could be obtained using a supersonic Laval nozzle integrated on a standard torch. 50 to 100 um YSZ coatings with porosity of near 1% could be obtained using this technique at relatively high deposition rates (10g/min.). Attention has been given to the thin coating porosity measurement by using a proper calibration and back scattered electron micrographs of the deposit cross-section coupled with image analysis. Absolute porosity has been measured by using this technique described in another paper of the same conference.
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Nava, Y., Z. Mutasim et M. Coe. « Ceramic Abradable Coatings for Applications up to 1100 °C ». Dans ITSC2001, sous la direction de Christopher C. Berndt, Khiam A. Khor et Erich F. Lugscheider. ASM International, 2001. http://dx.doi.org/10.31399/asm.cp.itsc2001p0119.

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Abstract Ceramic-based thermal spray coatings have been lately introduced as abradable materials for applications in the hot section of gas turbine engines. This paper reports abradable characteristics and high-temperature oxidation resistance of plasma sprayed yttria-stabilized zirconia (YSZ) and agglomertated yttria-stabilized zirconia with Polyester (YSZP). Unlike conventional blended coatings, agglomerated YSZP plasma-sprayed coatings are more forgiving to technique and processing parameter variations during the thermal-spray operation. The abradability studies were conducted on a test rig at temperatures of 600, 900 and 980 °C using coated (hardened) and uncoated blades. The oxidation resistance of the coatings was measured as a function of the cycles to failure and was conducted at temperature ranges of 930 to 1150°C in still air. Results showed that the ceramic coating, YSZ-Pl, was capable of withstanding both mid- and high-temperature rubs with little deleterious effects to the uncoated blade-tip across the temperature range, and presented a cyclic oxidation resistance comparable to that of YSZ coating.
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Zhang, C., H. Liao, M. Planche, C. Coddet, C. X. Li, G. J. Yang et C. J. Li. « Study on Gas Permeation Behaviour Through Atmospheric Plasma-Sprayed Yttria Stabilized Zirconia Coating ». Dans ITSC2008, sous la direction de B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima et G. Montavon. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2008. http://dx.doi.org/10.31399/asm.cp.itsc2008p0398.

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Abstract Gas permeation behaviour through atmospheric plasma-sprayed 8 mol% yttria stabilized zirconia (YSZ) electrolyte coating was studied experimentally. YSZ coatings were fabricated using different powder feedstock. The temperature and velocity of in-flight particles during spraying were measured with a diagnostic system. The results showed that particle temperature and velocity were significantly influenced by the size of powders. The gas permeability of these coatings was estimated by a specific instrument with pure O2, N2 and H2. It was found that the gas permeability was reduced by decreasing the size of powder. Gas permeation behaviour through plasma-sprayed YSZ coating was studied. Transition flow was compatible to gas permeation behaviour for all three plasma-sprayed YSZ coatings. The relationship between gas permeation behaviour and coating microstructure is discussed in this article.
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