The Effects of High Temperature Exposure on the Durability of Thermal Barrier Coatings

Yanar, N. M.; Stiger, M. J.; Maris-Sida, M.C.; Pettit, F. S.; Meier, G. H.

doi:10.4028/www.scientific.net/kem.197.145

Cited by 18 publications

(16 citation statements)

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“…Samples were placed on curved alumina platens in a conventional bottom-loading cyclic oxidation furnace. The oxidation cycle was modeled after the work of Meier and co-workers 38 and consisted of ramping to 1,100°C in 10 min., followed by an isothermal dwell period of 45 min. at 1,100°C before cooling to 100°C in 10 min.…”

Section: Characterization Of Low Activity Ruthenium-modifi Ed Bond Comentioning

confidence: 99%

Ruthenium-containing bond coats for thermal barrier coating systems

Tryon

Cao

Murphy

et al. 2006

JOM

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High-Temperature Applications Research SummaryBond coats for zirconia-based thermal barrier coating systems applied to nickel-based superalloys are typically composed of the B2 NiAl phase. Since RuAl has the same B2 crystal structure but a melting point 400°C higher than NiAl, ruthenium-modifi ed aluminide bond coats could provide improved system temperature capability. Creep experiments on ternary Al-Ni-Ru alloys demonstrate greatly improved creep properties with increasing ruthenium content. Processing paths for rutheniummodifi ed NiAl-based bond coatings have been established within the bounds of commercially available coating systems. The oxidation resistance of rutheniummodifi ed bond coats during thermal cycling has been examined, and potential thermal barrier coating system implications are discussed.

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Section: Characterization Of Low Activity Ruthenium-modifi Ed Bond Comentioning

confidence: 99%

Ruthenium-containing bond coats for thermal barrier coating systems

Tryon

Cao

Murphy

et al. 2006

JOM

View full text Add to dashboard Cite

show abstract

“…After cleaning in acetone the samples were placed on curved alumina platens in a conventional bottom-loading cyclic oxidation furnace. The oxidation cycle was modeled after that of Meier and co-workers [50] and consisted of ramping to 1100°C in 10 minutes, followed by an isothermal dwell period of 45 minutes at 1100°C before cooling to 100°C in 10 minutes. Exposures included 15, 30, 60, and 120 cycles for the low activity samples and 15 and 30 cycles for the high activity specimens.…”

Section: Oxidationmentioning

confidence: 99%

Multilayered ruthenium-modified bond coats for thermal barrier coatings

Tryon

Feng

Pollock

et al. 2006

Metall Mater Trans A

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Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal barrier coatings have been developed via low activity chemical vapor deposition and high activity pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed when switching processes. The structural evolution of each coating at various stages of the fabrication process has been and subsequent cyclic oxidation is presented, and the relevant interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in need of further improvement in both cases.

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“…In-service degradation, accompanied by increased risk of spallation, is the major concern. There are strong indications [1][2][3][4][5][6][7][8] that spallation is commonly related to sintering and associated stiffening of the zirconia top coat, particularly [9][10][11][12][13][14] when this is accelerated by the presence of impurities, such as calcia-magnesia-alumina-silica (CMAS), either from the original powder or deposited during service. This concern is likely to become even more prominent as turbine entry temperatures continue to rise.…”

Section: Introductionmentioning

confidence: 99%

A sintering model for plasma-sprayed zirconia TBCs. Part I: Free-standing coatings

2009

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A sintering model is presented for prediction of changes in the microstructure and dimensions of free-standing, plasma-sprayed (PS) thermal barrier coatings (TBCs). It is based on the variational principle. It incorporates the main microstructural features of PS TBCs and simulates the effects of surface diffusion, grain boundary diffusion and grain growth. The model is validated by comparison with experimental data for shrinkage, surface area reduction and porosity reduction. Predicted microstructural changes are also used as input data for a previously developed thermal conductivity model. Good agreement is observed between prediction and measurement for all these characteristics. The model allows separation of the effects of coating microstructure and material properties, and captures the coupling between densifying and non-densifying mechanisms. A sensitivity analysis is presented, which highlights the importance of the initial pore architecture. Predictions indicate that the microstructural changes which give rise to (undesirable) increases in thermal conductivity and stiffness are very sensitive to surface diffusion.

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The Effects of High Temperature Exposure on the Durability of Thermal Barrier Coatings

Cited by 18 publications

References 0 publications

Ruthenium-containing bond coats for thermal barrier coating systems

Ruthenium-containing bond coats for thermal barrier coating systems

Multilayered ruthenium-modified bond coats for thermal barrier coatings

A sintering model for plasma-sprayed zirconia TBCs. Part I: Free-standing coatings

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