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Showing 1 to 20 of 27 for “"TBCs"”.
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Effect of thermal and mechanical loadings on the degradation and failure modes of APS TBCs
Thermal barrier coatings (TBCs) are applied for the thermal protection of hot section components of gas turbines to improve their life-time or to raise the power and thermal efficiency of the gas turbine by increasing the turbine inlet temperature. TBCs limit the lifetime of the coated component …
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Theoretical study on toughening and design against fracture of functionally graded thermal barrier coatings
Functionally graded thermal barrier coatings (FG TBCs) are advanced multi-phase composites that are engineered to have a smooth spatial gradation of material constituents, which are normally ceramics and metal. The smooth gradation results in the reduction of thermal stresses, minimization or …
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Effects Of Bond Coat Surface Preparation On Thermal Cycling Lifetime And Failure Characteristics Of Thermal Barrier Coatings
Thermal barrier coatings (TBCs) have been widely used in gas turbine engines to protect the underlying metal from high operating temperature so as to improve the durability of the components and enhance the engine efficiency. However, since the TBCs always operate in a demanding high-temperature …
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Nondestructive Evaluation Of Thermal Barrier Coatings With Thermal Wave Imaging And Photostimulated Luminescence Spectroscopy
… limits is by applying thermal barrier coatings (TBCs) to hot section components. TBCs provide a thermal gradient between the hot gases and metallic substrate, and allow an increase in turbine inlet temperatures of 100-150ºC. However, spallation of TBCs can cause catastrophic failure of turbine …
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Non-destructive Microstructural Evaluation Of Yttria Stabilized Zirconia, Nickel Aluminides And Thermal Barrier Coatings Using Electrochemical Impedance Spectroscopy
… gas turbine engines, thermal barrier coatings (TBCs) have gained significant applications in increasing the gas inlet temperatures. Insulating characteristics of ceramic TBCs allow the operation at up to 150~250 ˚C higher gas temperatures. Because of the severe turbine engine operating …
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Failure mechanisms of thermal barrier coatings for high temperature gas turbine components under cyclic thermal loading
The mechanical behavior of PYSZ TBCs, deposited by EB-PVD and APS techniques, has been studied under thermal cyclic and isothermal loading. Two types of bond coats were chosen for the different multilayer systems: a single phase (Ni,Pt)-aluminide and a NiCoCrAlY overlay layer in the case of the …
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Stress and Damage Analyses of Thermal Barrier Coatings Under Cyclic Thermal Loading Conditions
… failure of the thermal barrier coatings (TBCs) system is a preliminary phenomenon that can significantly limit their applications in gas turbine engines. The delamination of TBCs occurs typically at interfaces between the top coat and bond coat due to thermal mismatch stress via both crack …
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Study of microstructure effect on the thermal properties of Yttria-stabilized-Zirconia thermal barrier coatings made by atmospheric plasma spray and pressing machine
Thermal barrier coatings (TBCs) are used in gas turbine engines to achieve a higher working temperature and thus lead to better efficiency. Yttria-Stabilized-Zirconia (YSZ), a material with low thermal conductivity, is commonly used as the top coat layer to provide the thermal barrier effect. In …
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The effect of sintering and CMAS on the stability of plasma-sprayed zirconia thermal barrier coatings
State of the art thermal barrier coatings (TBCs) for gas turbine applications comprise (7 wt.%) yttria partially stabilized zirconia (7YSZ). 7YSZ offers a range of attractive functional properties – low thermal conductivity, high thermal expansion coefficient and high in-plane strain tolerance. …
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Microstructural characterization of a plasma sprayed ZrO2-Y2O3-TiO2 thermal barrier coating
… ceramic coats as thermal barrier coatings (TBCs) for the protection of metallic structures and equipment from severe thermal, abrasive and corrosive conditions has been documented extensively in the last two decades. The state-of-the-art TBCs consist of a double layer coat. a top ceramic …
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Combined Tension-Torsion Loading of Braided Composite Structures
… and Aramid 2D tubular braided composites (TBCs) were assessed and compared under coupled tension-torsion loading. Failure mechanism of braids was investigated by the plane stress theory. A contact-free three-dimensional digital image correlation (3D DIC) technique was used to derive …
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Cure Kinetics of Two Part Epoxy Resin and the Effect on Characterization of Thermal Barrier Coatings
… and therefore thermal barrier coatings (TBCs) composed of yttria-stabilized zirconia (YSZ) play an important role in improving the performance of the components that make up the engine. Failure of the TBC could lead to catastrophic events, thus requiring consistent and accurate …
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Bondcoat developments for thermal barrier coatings
… the last few years, in thermal barrier coatings (TBCs). TBCs are duplex coating systems consisting of a thin, insulating, ceramic layer over a metallic bondcoat. The bondcoat provides both environmental protection and the necessary adhesive interface to maintain the adherence of the ceramic during …
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On the Rumpling Instability in Thermal Barrier Systems
"Thermal barrier coatings (TBCs) are protective multi-layered metal-ceramic coatings used in hot sections of jet engines and gas turbines. The TBCs are composed of a superalloy substrate, an intermediate metallic bond coat (BC) and a ceramic topcoat. The TBCs are beset by reliability problems …
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Thermomechanical properties of novel lanthanum zirconate based thermal barrier coatings - an integrated experimental and modeling study
<p>Thermal barrier coatings (TBCs) are refractory materials deposited on gas turbine components, which provide thermal protection for metallic components at operating conditions. The current state-of-art TBC material is yttria-stabilized zirconia (YSZ), whose service temperature is limited to 1200 …
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Finite element simulation of stress evolution in thermal barrier coating systems
… Damage in Thermal Barrier Coating Systems (TBCs) is related to oxidation of the Bond Coat, sintering of the ceramic, thermal mismatch of the material constituents, complex shape of the BC/TGO/TBC interface, redistribution of stresses via creep and plastic deformation and crack resistance. In …
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Investigation into the optimal cooling configuration for a gas turbine airfoil utilizing a thermal barrier coating
… This result along with increased reliability of TBCs suggests that TBCs should be considered when determining optimal integrated cooling configurations for an airfoil. In this study RANS computational simulations were used to determine the optimal cooling configuration for a flat plate with a …
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Hot corrosion behaviour of new candidates for thermal barrier coatings application in turbine simulated environments
Thermal barrier coatings (TBCs) are used gas turbine engines. The current material of choice (YSZ) degrades when it contacts with impurities arise from low quality fuels such vanadium and sulfur. YSZ cannot be used in temperature higher than 900˚C. Higher efficiency and performance of gas turbine …
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Ermittlung des Verformungs- und Schädigungsverhaltens von Wärmedämmschichtsystemen
… air flow. The use of thermal barrier coatings (TBCs) has great potential for increasing the thermal efficiency, while at the same time limiting metal temperatures of the blades. The exploitation of the potential of TBCs has, however, been hampered by the lack of systematic data concerning the …
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Thermal Evolution of MAS, YSZ and GZO Thermal Barrier Coating Materials in Benign and CMAS Rich Environments
Abradable thermal barrier coatings (TBCs) play a crucial role as thermal insulators and dynamic seals in turbine engines. However, the conventional choice, yttria-stabilised zirconia (YSZ), exhibits vulnerabilities, such as sintering induced stiffening, phase transformations, and susceptibility to …
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