Review on Nickel Aluminide based Bond Coat Properties and Oxidation Performance for Thermal Barrier Coating (TBC) Application

Thermal Barrier Coating (TBC) as protective coatings are applied to maintain efficiency and prevent structural failures mainly in gas turbine system. This paper reviews on recent bond coating from Nickel aluminide bond coat with addition of Reactive Elements (RE). This paper also reviews the major concern in TBC with presence of different Reactive Element (RE) added in term of RE composition, properties and oxidation test performance. Recent studies are more focusing on few REs including Ce, Hf, La, Y and Zr based on oxidation property test results. The comparisons clearly show that ceramics addition are superior for bond coat mechanical and thermal properties improvement while RE addition such as Ce and Zr present excellent oxidation performance at 900°C and above.

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Spatially varying microhardness in a platinum-modified nickel aluminide bond coat in a thermal barrier coating system

Scripta Materialia ◽

10.1016/j.scriptamat.2005.12.034 ◽

2006 ◽

Vol 54 (7) ◽

pp. 1265-1269 ◽

Cited By ~ 9

Author(s):

M ZHANG ◽

A HEUER

Keyword(s):

Thermal Barrier Coating ◽

Bond Coat ◽

Nickel Aluminide ◽

Thermal Barrier ◽

Coating System ◽

Thermal Barrier Coating System ◽

Barrier Coating ◽

Spatially Varying

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A Statistical Assessment of the Damage State in Plasma-Sprayed Thermal Barrier Coating

Volume 3: Turbo Expo 2003 ◽

10.1115/gt2003-38790 ◽

2003 ◽

Cited By ~ 1

Author(s):

X. J. Wu ◽

P. C. Patnaik ◽

M. Liao ◽

W. R. Chen

Keyword(s):

Thermal Barrier Coating ◽

Bond Coat ◽

Damage Evolution ◽

Protective Coatings ◽

Mechanistic Model ◽

Thermal Barrier ◽

Air Plasma ◽

Damage State ◽

Barrier Coating ◽

Plasma Sprayed

Thermal barrier coatings (TBC), which consist of yttria-partially-stabilized zirconia top coat and metallic bond coat deposited onto superalloy substrate, are favorably used as protective coatings of the hot section parts in advanced gas turbine engines to withstand increased inlet temperatures and thus improve engine performance. However, understanding and modeling the damage evolution in TBC under service exposed conditions still remain to be a challenge. This is due to the failure by the coupled effects of the external load-environment, the thermal expansion mismatch between the bond coat and TBC, microstructure of the coating, and degradation of the bond coat. In this study, the damage state in an air-plasma-sprayed APS) thermal barrier coating system was assessed using metallurgical and statistical methods. The damage evolution in the TBC can thus be described with a high degree of confidence. A mechanistic model, representing the micro-cracking mechanism, is presented and its prediction is also assessed on a statistical basis.

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Oxygen Transport Through the Zirconia Top Coat in Thermal Barrier Coating Systems

Thermal Spray 1998: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc1998p1589 ◽

1998 ◽

Author(s):

A.C. Fox ◽

T.W. Clyne

Keyword(s):

Thermal Barrier Coating ◽

Bond Coat ◽

Ionic Conduction ◽

Gas Permeability ◽

Gas Permeation ◽

Thermal Barrier ◽

Barrier Coating ◽

Oxygen Gas ◽

Plasma Sprayed ◽

Tbc Systems

Abstract The gas permeability of plasma sprayed yttria-stabilised zirconia coatings has been measured over a range of temperature, using hydrogen and oxygen gas. The permeability was found to be greater for coatings produced with longer stand-off distances, higher chamber pressures and lower torch powers. Porosity levels have been measured using densitometry and microstructural features have been examined using SEM. A model has been developed for prediction of the permeability from such microstructural features, based on percolation theory. Agreement between predicted and measured permeabilities is good. Ionic conduction through the coatings has also been briefly explored. It is concluded that transport of oxygen through the top coat in thermal barrier coating (TBC) systems, causing oxidation of the bond coat, occurs primarily by gas permeation rather than ionic conduction, at least up to temperatures of about 1000°C and probably up to higher temperatures. Top coat permeabilities appreciably below those measured will be required if the rate of bond coat oxidation is to be reduced by cutting the supply of oxygen to the interface.

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On the Change in Stress State Associated with Bond Coat Oxidation during Heat Treatment of a Thermal Barrier Coating System

Thermal Spray 1997: Proceedings from the United Thermal Spray Conference ◽

10.31399/asm.cp.itsc1997p0267 ◽

1997 ◽

Author(s):

Y.C. Tsui ◽

T.W. Clyne ◽

R.C. Reed

Keyword(s):

Heat Treatment ◽

Stress State ◽

Oxide Layer ◽

Thermal Barrier Coating ◽

Bond Coat ◽

Driving Forces ◽

Lateral Strain ◽

Thermal Barrier ◽

Residual Stress State ◽

Barrier Coating

Abstract Thermal barrier coating systems have been heat treated in order to study the oxidation kinetics of the bond coat. All the surfaces of Ni superalloy substrates were sprayed with ~100 μm of a NiCrAlY bond coat, with or without ~250 μm of a ZrO2 top coat. Thermogravimetric analysis (TGA) was used to monitor continuously the mass change as a result of oxidation of the bond coat during heating at 1000°C for 100 hours in flowing air. In addition, some specimens were heated to 1000°C in static air, cooled to room temperature, weighed and re-heated cyclically. The total exposure time was 1000 hours. Rates of weight gain were found to be higher for the cycled specimens, despite the absence of air flow. This is attributed to damage to the oxide film, which was predominantly α-Al2O3, as a consequence of differential thermal contraction stresses. The changing residual stress state during heat treatment was predicted using a previously-developed numerical model. A thin (1 mm) substrate with ~100 μm bond coat and ~250 μm ZrO2 top coat was used in these simulations, which incorporated creep of the bond coat and the lateral strain associated with oxidation. It is concluded from these computations that, while high stresses develop in the oxide layer, the associated driving forces for interfacial debonding remain relatively low, as do specimen curvature changes. It seems likely that coating spallation after extensive oxide layer formation arises because the interface is strongly embrittled as the layer thickens.

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