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Showing 1 to 20 of 35 for “"barrier coating"”.
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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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Atomistic and finite element modeling of zirconia for thermal barrier coating applications
… 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) 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
… 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 coat. …
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Investigation into the optimal cooling configuration for a gas turbine airfoil utilizing a thermal barrier coating
… 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 suggests that …
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In situ control of lubricant properties for reduction of power cylinder friction through thermal barrier coating
… the implementation of insulation or thermal barrier coating (TBC) as a means of reducing local oil viscosity and power cylinder friction in internal combustion engines with minimal side effects of increased wear. TBC is selectively applied to the outside diameter of the cylinder liner to …
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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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The effect of bond coat oxidation on the microstructure and endurance of two thermal barrier coating systems
… oxidation 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). …
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Air Plasma Sprayed Thermal Barrier Coatings: Experiments and Finite Element Analysis
… 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 and key …
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Impact of aerothermal modeling on the estimation of turbine blade life
… noise parameters, along with metal and thermal barrier coating conductivity, thermal barrier coating thickness, internal cooling temperature, and internal heat transfer coefficient, in three probabilistic blade life calculations. Consistent with the deterministic findings, a weak to moderate …
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Surface Reaction Mechanisms for Plasma Processing of Semiconductors
… etching and the deposition of a continuous barrier layer are critical processes for integration PS as ILDs. To investigate these issues, a reaction mechanism for plasma stripping of residual fluorocarbon polymer using oxygen-based chemistries has been developed and incorporated into the …
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Ultra-thin moisture barrier coatings for passive components
… corrosion. Conventional protective coatings, such as epoxies and polyurethanes, are extremely thick--usually over 1 mm. Previous work has shown that a thick coating leads to a large equivalent series inductance (ESL) of the capacitor, and negatively affects the capacitor performance. …
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Experimental and Computational Investigation of Thermal-Flow Characteristics of Gas Turbine Reverse-Flow Combustor
… the modern advancement in metallurgy and thermal-barrier coating technologies, it may become possible to remove this sheath to recover the pressure losses without melting the combustor chamber. However, without the sheath, the flow inside the dump diffuser may exert nonuniform cooling on the …
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Modeling Behaviour of Damaged Turbine Blades for Engine Health Diagnostics and Prognostics
… damage to the structural material and thermal barrier coating as well as the onset of damage causing structural failure.
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Structural and Thermal Properties of Ignition Resistant Coatings for Reusable Rocket Engines
… relates my investigation of an environmental barrier coating formulation, first developed for Russian RD-180 engines, which prevents ignition due to particle impact on ox-turbopump turbine. Ignition resistant environmental barrier coatings are of particular interest for reusable rocket …
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Functional thin film polymers for biopassivation of neuroprosthetic implants
… materials for use in biopassive neural probe coatings have been developed and validated. These polymers are synthesized by initiated chemical vapor deposition to allow conformal, pin-hole free coatings of high aspect ratio neural probe assemblies. The first developed material is an …
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Development of a Humidity-Resistant Coating to Impart High Oxygen Barrier Performance to Food Packaging Films
<p>Oxygen barrier coatings have the potential to greatly extend the lifetime of certain food products by incorporating them into existing food packaging. Present technologies face definite challenges of maintaining high performance, while attaining simple and inexpensive preparation methods. The …
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Geopolymer-derived ceramics and composites
… new candidate materials for environmental barrier applications. The materials were studied with in situ high temperature synchrotron X-ray diffraction to explore the atomic mechanisms responsible for the thermal evolution of these compounds. The framework distortions identified were then …
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Study of the Structure-Property Relationships That Determine the Effects of Latexes and Starch Containing Latex Emulsions on the Performance of the Barrier Coatings (Sub-coat) for Paper
… on the receiver sheet below. Under this capsule coating is a barrier coat or sub-coat, which is applied to the back of the original written sheet. The coating limits the encapsulated dye from absorbing into the original written sheet and increases the dye transferring onto the copy receiver …
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Finite element analysis of combined fracture and delamination on coated substrate under normal and tangential loading
Coating systems provide substrate protection from mechanical and thermal failure. Coating is subjected to contact loading of normal and tangential loading, originated from contact pressure and sliding contact. In this thesis, aeroengine brittle material has been modelled to simulate coating failure …
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