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Showing 1 to 20 of 64 for “"thermal barrier"”.
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Bondcoat developments for thermal barrier coatings
… lead to an interest, over 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 …
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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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The Constitutive Behavior of Thick Thermal Barrier Coatings
Plasma-sprayed thick thermal barrier coatings on the order of a millimeter are currently being developed for use in diesel engines with operating temperatures of about 800°C. In this environment, coatings will be subjected to thermomechanical compressive strain cycles that correspond to the …
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The Deformation and Fracture of Thick Thermal Barrier Coatings
Plasma-sprayed thick thermal barrier coatings (TTBCs) are being developed for thermal protection of diesel engine components in high temperature service. Comparing to thin thermal barrier coatings used in gas turbine industry, increased thickness causes some TTBCs failure to occur within the bulk …
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Geometric Effects of Thermal Barrier Coating Damage on Turbine Blade Temperatures
<p>Thermal barrier coatings (TBC) found on turbine blades are a key element in the performance and reliability of modern gas turbines. During the life of the turbine components, the TBC surface may be damaged due to manufacturing imperfections, handling damage, service spalling, or service impact …
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Air Plasma Sprayed Thermal Barrier Coatings: Experiments and Finite Element Analysis
… failure mechanism of an air plasma sprayed thermal barrier coating commonly used in combustor applications, and to use that failure mechanism as a basis in developing a life prediction strategy. The research consisted of an experimental phase, in which the failure mechanism was identified …
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Bonding mechanisms in the application of thermal barrier coatings to turbine blades.
Thermal barrier coatings (TBC's) are used to protect gas turbine blades from environmental degradation as well as to increase thermodynamic efficiency. Most TBC systems consist of a ceramic thermal barrier coating such as partially stabilized zirconia adhering to an oxidation resistant bond coat, …
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Atomistic and finite element modeling of zirconia for thermal barrier coating applications
… Due to its high melting temperature, low thermal conductivity, and high-temperature stability, zirconia based ceramics have been widely used for thermal barrier coatings (TBCs). When TBC is exposed to thermal cycling during real applications, the TBC may fail due to several mechanisms: (1) …
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Microstructural characterization of a plasma sprayed ZrO2-Y2O3-TiO2 thermal barrier coating
The use of plasma sprayed 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 …
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In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments
Thermal Barrier Coatings have been used for decades to impose a thermal gradient between the hot combustion gases and the underlying superalloy substrate in engine turbine blades. Yttria Stabilized Zirconia (YSZ) is an industry standard high temperature ceramic for turbine applications. The …
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Modelling Thermal Conductivity of Porous Thermal Barrier Coatings for High-Temperature Aero Engines
Thermal Barrier Coatings (TBC) are used to shield hot sections of gas turbine engines, helping to prevent the melting of metallic surfaces. TBC is a sophisticated layered system that can be divided into top coat, bond coat, and the super-alloy substrate. The highly heterogeneous microstructure of …
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Stress and Damage Analyses of Thermal Barrier Coatings Under Cyclic Thermal Loading Conditions
The premature 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 …
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Nondestructive Evaluation Of Thermal Barrier Coatings With Thermal Wave Imaging And Photostimulated Luminescence Spectroscopy
… beyond material 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 …
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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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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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Investigation into the optimal cooling configuration for a gas turbine airfoil utilizing a thermal barrier coating
… cooling effectiveness of airfoil's utilizing a thermal barrier coating. In this study it was found that the addition of a 0.84D thick TBC to an internally cooled flat plate yields a 130% improvement in the overall cooling effectiveness. This result along with increased reliability of TBCs …
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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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Deposition of yttria-stabilized zirconia thermal barrier coatings by laser-assisted plasma coating at atmospheric pressure
… to deposit the yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) at atmosphere pressure. These coatings can be applied on silicon wafers, and multi-layer nickel-based superalloy substrates (René N5), by a new deposition technique called laser-assisted plasma coating at atmospheric …
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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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