The wetting behavior of NiAl and NiPtAl on polycrystalline alumina

Gauffier, A.; Saiz, Eduardo; Tomsia, Antoni P.; Hou, P.Y.

doi:10.1007/s10853-007-2093-9

Cited by 14 publications

(5 citation statements)

References 35 publications

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“…[9] The mechanism by which Pt acts is different from that of reactive elements (REs) such as hafnium and yttrium, which as mentioned above are often added to the bond coat. Pt has been shown to drastically improve TBC lifetime, but although Pt has been used in commercial bond coats for several decades, experiments have been unable to determine how Pt's beneficial effects are achieved.…”

Section: Introductionmentioning

confidence: 99%

“…Pt has been shown to drastically improve TBC lifetime, but although Pt has been used in commercial bond coats for several decades, experiments have been unable to determine how Pt's beneficial effects are achieved. [9] The mechanism by which Pt acts is different from that of reactive elements (REs) such as hafnium and yttrium, which as mentioned above are often added to the bond coat. While REs slow the growth and alter the microstructure of the TGO, Pt…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Platinum on Diffusion Kinetics in β‐NiAl: Implications for Thermal Barrier Coating Lifetimes

Marino

Carter

2009

ChemPhysChem

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Platinum is added to thermal barrier coatings (TBCs) as it is observed empirically to extend their lifetime, but the mechanism by which Pt acts is unknown. Since Pt has been proposed to alter diffusivities in NiAl, a key component of TBCs, we use first-principles quantum mechanics calculations to investigate atomic level diffusion mechanisms. Here, we examine the effect of Pt on five previously proposed mechanisms for Ni diffusion in NiAl: next-nearest-neighbor jumps, the triple defect mechanism, and three variants of the six jump cycle. We predict that Pt increases the rate of Ni diffusion by stabilizing point defects and defect clusters that are diffusion intermediates. Previously, we predicted the triple defect mechanism to be a dominant Ni diffusion mechanism; it simultaneously results in long-range Al diffusion in the opposite direction. Since Pt increases the rate of Ni diffusion, it also increases Al diffusion in NiAl, which may be key to extending the coating lifetime.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Platinum on Diffusion Kinetics in β‐NiAl: Implications for Thermal Barrier Coating Lifetimes

Marino

Carter

2009

ChemPhysChem

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“…Various ceramic-to-metal joining techniques, utilizing or not a liquid phase, have been developed and improved over the past 60 years, among which solid-state diffusion bonding [2][3][4][5][6][7] and reactive metal brazing [2,5,[7][8][9][10]. Both processes are widely used, especially because strong and gas proof bonds can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal residual stresses on the strength for both alumina/Ni/alumina and alumina/Ni/nickel alloy bimaterials

et al. 2009

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International audienceThis paper describes some technical limitations encountered in joining ceramics-ceramics or ceramics-metals, and how, to some extent, they have been practically overcome. The effect of the residual stresses on the strength of joints fabricated between alumina-alumina or alumina and the nickel base alloy HAYNES 214TM using a solid-state bonding technique with Ni interlayer was studied. Finite element analyses (FEA) for the elastic-plastic and elastic-plastic-creep behavior have also been used to better design the joints and to predict their performance. It was found that the residual stresses caused by the thermal expansion mismatch between alumina (Al2O3) and the Ni-based superalloy (HAYNES 214TM) have severely deteriorated the joints compared to Al2O3-Al2O3 joint fabricated with the same solid-state bonding parameters. The high residual stresses zones obtained through the FEA simulation fitted well with the fractographic observations of the Al2O3/Ni/HAYNES 214TM joints. Also, in order to use the joint material as a structural material, the study about the effect of geometrical parameters has been performed. Optimal geometries have been determined

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“…Many Ni-based superalloys contain Al up to 6 wt% which is added in order to improve oxidation resistance or to form c 0 hardening precipitates [1]; also, alloys based on the intermetallic compounds Ni 3 Al and NiAl exist owing to their lightness, strength, corrosion resistance and longer lifespan [2]. While an extensive literature can be found about the wetting of Ni-based alloys on Al 2 O 3 including Ni-Al alloys [3][4][5][6], only a few articles deal with the wettability of pure Ni and Ni-based alloys on ZrO 2 [7][8][9] and, to the best of our knowledge, the effect of Al solutes has never been studied before for these systems. Pure Al was observed to exhibit a contact angle of 88°and a slight interfacial reaction in contact with ZrO 2 at 1000°C in vacuum [10].…”

Section: Introductionmentioning

confidence: 99%

Wetting and interfacial reactivity of Ni–Al alloys with Al2O3 and ZrO2 ceramics

et al. 2021

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The isothermal wetting, spreading behaviour and interfacial reactivity of NiAl1, NiAl10 and NiAl25 alloys (1, 10, 25 at% Al, respectively) on monocrystalline alumina (sapphire) and polycrystalline zirconia oxides stabilized with MgO (stoichiometric and non-stoichiometric ones) were studied by means of the sessile drop method at 1500°C in vacuum. A detailed characterization of solidified couples was performed in order to analyse the final interfacial microstructure and microchemistry. The results were discussed in terms of chemical interactions and by means of ad-hoc calculated phase diagrams. The final contact angles varied with the content of Al leading to a slight wetting situation (contact angle h \ 90°), for the NiAl25 alloy on both sapphire and zirconia. The contact of liquid Ni-Al alloys on sapphire was not accompanied by interfacial chemical reaction. The wetting of pure Ni and NiAl1 alloy was found to be worse for fully stoichiometric ZrO 2 compared with under-stoichiometric ZrO 2-x by virtue of the increased metallicity of the latter. On the other hand, the formation of interfacial a-Al 2 O 3 for the NiAl10 and NiAl25 alloys on ZrO 2 , as foreseen by thermodynamic modelling and experimentally confirmed by transmission electron microscopy characterization, determined the kinetics of wetting and the final contact angle whatever the zirconia stoichiometry.

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The wetting behavior of NiAl and NiPtAl on polycrystalline alumina

Cited by 14 publications

References 35 publications

The Effect of Platinum on Diffusion Kinetics in β‐NiAl: Implications for Thermal Barrier Coating Lifetimes

The Effect of Platinum on Diffusion Kinetics in β‐NiAl: Implications for Thermal Barrier Coating Lifetimes

Effect of thermal residual stresses on the strength for both alumina/Ni/alumina and alumina/Ni/nickel alloy bimaterials

Wetting and interfacial reactivity of Ni–Al alloys with Al2O3 and ZrO2 ceramics

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