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Showing 1 to 20 of 22 for “"Bond coat"”.
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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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The effect of bond coat oxidation on the microstructure and endurance of two thermal barrier coating systems
… tests were carried out on two thermal barrier coating systems consisting of a CMSX-4 nickel-based superalloy substrate, NiCoCrAlY overlay bond coat applied by two different techniques and a yttria stabilised zirconia topcoat applied by electron beam physical vapour deposition (EBPVD). The bond …
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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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Einfluss der Bondcoatzusammensetzung und Herstellungsparameter auf die Lebensdauer von Wärmedämmschichten bei zyklischer Temperaturbelastung
In the present study the influence of the bond coat composition on the lifetime of thermal barrier coatings during thermal cycling was investigated. The knowledge, that the reactive elements (RE), which are essential for the improvement of the oxide scale adhesion, are “lost”, during the bond coat …
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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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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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Air Plasma Sprayed Thermal Barrier Coatings: Experiments and Finite Element Analysis
… 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 and key features …
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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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Influence of composition and processing on the oxidation behavior of MCrAlY-coatings for TBC applications
… of the thermally grown oxide (TGO) to the bond coat is recognized to be crucial for the lifetime of thermal barrier coatings (TBC) in aircraft engine and gas turbine blades. The stability of the system has to be guaranteed over extended service times (around 25000h) at high operation …
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Neue Verfahren zur Analyse des Verformungs- und Schädigungsverhaltens von MCrAlY-Schichten im Wärmedämmschichtsystem
Thermal barrier coatings applied to thermally highly loaded areas of land-based gas turbines represent a promising tool to increase efficiency and to reduce emissions in the conventional electric power production. A basic requirement to achieve reliable use of thermal barrier coatings is an …
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Optimized Surface Roughening by Pulsed Waterjet for Suitable Adhesion Strength of Plasma Transferred Wire Arc Coating
… for engine remanufacturing to deposit the top-coat. The idea behind this project is to eliminate the expensive nickel-aluminum pre-bond coat by optimizing the surface roughness profile of the substrate to provide acceptable mechanical bonding between the coating and substrate. In this study, …
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Finite element simulation of stress evolution in thermal barrier coating systems
… to extreme high temperature require protective coatings. To design reliable components, a better understanding of the coating failure mechanisms is required. Damage in Thermal Barrier Coating Systems (TBCs) is related to oxidation of the Bond Coat, sintering of the ceramic, thermal mismatch of …
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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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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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Ermittlung des Verformungs- und Schädigungsverhaltens von Wärmedämmschichtsystemen
… the cooling 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 …
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Failure mechanisms of thermal barrier coatings for high temperature gas turbine components under cyclic thermal loading
… 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 EB-PVD and APS TBC respectively. The degradation of APS TBCs, i.e. crack evolution and oxidation kinetics …
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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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Atomistic and finite element modeling of zirconia for thermal barrier coating applications
… have been widely used for thermal barrier coatings (TBCs). When TBC is exposed to thermal cycling during real applications, the TBC may fail due to several mechanisms: (1) phase transformation into yttrium-rich and yttrium-depleted regions, When the yttrium-rich region produces pure …
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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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Nondestructive Evaluation Of Thermal Barrier Coatings With Thermal Wave Imaging And Photostimulated Luminescence Spectroscopy
… 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 catastrophic failure of …
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