Examination of the platinum effect on the oxidation behavior of nickel-aluminide coatings

Hou, P.Y.; Tolpygo, V.K.

doi:10.1016/j.surfcoat.2007.06.013

Cited by 97 publications

(30 citation statements)

References 13 publications

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“…Experimental results on model alloys [18] and coatings [46] have indeed shown that Pt eliminates S segregation on bNiAl, and the current study shows that it reduces S segregation on c ? c 0 alloys, but there has not been any clear indications as to how such effects are achieved, and why the effects are alloy phase dependent.…”

Section: Segregation Behaviorsupporting

confidence: 74%

Sulfur Segregation at Al2O3/γ-Νi + γ′-Ni3Al Interfaces: Effects of Pt, Cr and Hf Additions

2009

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The interfacial chemistry that developed as a result Al 2 O 3 -scale growth on c-Mi ? c 0 -Ni 3 Al alloys at 1150°C was studied using scanning Auger microscopy after the oxide layer was scratched to spall under ultra-high vacuum. The extent of scale spallation was used to evaluate semi-quantitatively the interfacial strength. The alloys investigated were primarily c 0 in structure, containing 22 at.% Al plus further additions of Pt, Cr and/or Hf. In the case of the binary c ? c 0 alloy, it was found that a sub-monolayer of sulfur segregated at the alloy/scale interface. Platinum reduced and hafnium eliminated sulfur segregation, but chromium enhanced it through Cr-S cosegregation, even on Pt-and Hf-containing alloys. Platinum also segregated slightly at the alloy/scale interface. The interface strength was a strong function of the sulfur content. Beyond the effect of eliminating S segregation, Pt and Hf both showed additional beneficial effects on alumina scale adhesion.

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Section: Segregation Behaviorsupporting

confidence: 74%

Sulfur Segregation at Al2O3/γ-Νi + γ′-Ni3Al Interfaces: Effects of Pt, Cr and Hf Additions

2009

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“…The effect of this enrichment might be to trap S in the metal, and as a consequence to limit the critical presence of S at the main metal/oxide interface. In this perspective, the results of this work are in agreement with the positive role of Pt for the TGO adherence as it is presented in the literature review [2,27,[35][36][37][38][39][40][41]. However, this work did not enabled an exact quantification of the amount of S at the metal/oxide interface.…”

Section: Study Of Sulfur Distribution In ''Commercial'' Tbc After Thesupporting

confidence: 84%

“…Compared to a non-modified coating, a gain in the adherence of the oxide scale is observed experimentally [2,26,[34][35][36][37]. The b-(Ni,Pt)Al coatings are currently used in the industry and their role in limiting the deleterious effect of S has been proven.…”

Section: Adopted Strategies To Counter the Sulfur Effectmentioning

confidence: 99%

Characterization of Sulfur Distribution in Ni-Based Superalloy and Thermal Barrier Coatings After High Temperature Oxidation: A SIMS Analysis

et al. 2009

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Sulfur segregation was characterized by secondary ion mass spectrometry (SIMS) in uncoated single-crystal Ni-based AM1 superalloys with various S contents and on NiPtAl, NiAl and NiPt bondcoats of complete TBC systems. In spite of technical difficulties associated with diffuse sputtered interfaces, an original sample preparation technique and a careful choice of analysis conditions enabled a chemical characterization of S distribution below metal/oxide interfaces. An initial heterogeneous distribution of S in as-received high S (3.2 ppmw) AM1 was measured. After oxidation, a S depletion profile formed, with a slope that depended on the initial bulk S content. GDMS measurements enabled a quantitative distribution of S in oxidized low S (0.14 ppmw) AM1 to be constructed and discussed in relation to equilibrium surface segregation of S on Ni. The quantity of S integrated in the thermally grown oxide (TGO) was estimated and found to be very similar to that measured from depletion found in the metal. Localized S enrichments in Pt-containing coatings are related to a possible beneficial trapping mechanism of Pt on the adherence of oxide scales.

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“…1719) The mechanisms 20) that Pt promotes the formation of the Al 2 O 3 scale and the mechanism 18,21) that Pt improves the adhesion of the Al 2 O 3 scale have been studied.…”

Section: Discussionmentioning

confidence: 99%

“…(3) Pt decreases the oxygen permeability into the alloy which decreases the critical Al concentration for Al 2 O 3 formation. Hou et al 18) claimed that the improvement in the adhesion of the Al 2 O 3 scale due to the Pt addition into Ni aluminide was attributed to the fact that S segregation at the scale/alloy interface was prevented by Pt. Cadoret et al 21) suggested that the improvement in the adhesion of the Al 2 O 3 scale due to Pt addition into Ni aluminide resulted from the fact that Pt slowed down the Al 2 O 3 -scale transformation from a metastable phase (ª phase) to a stable phase (¡ phase), and as a consequence, such a transformation lag decreases the stress evolved in the scale.…”

Section: Discussionmentioning

confidence: 99%

Preparation of Ni-Al-Pt Coating on Ni-6 at%Cr Alloy by Electrodeposition Method and Cyclic-Oxidation Resistance

et al. 2015

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The formation of a coating layer consisting of Ni, Al and Pt on a Ni-6 at% Cr alloy substrate was attempted by the electrodeposition of Pt and Al. The Pt and Al were deposited by electrolysis in an aqueous solution and molten salt, respectively. The cyclic oxidation resistance of the alloy with this coating was then evaluated in air at 1423 K. Particular attention has been paid to the effects of Pt in the coating and 6 at% Cr in the alloy substrate on the cyclic oxidation resistance. For the sample treated by Pt deposition, followed by the Al deposition, a coating layer comprised of an outer layer consisting of PtAl 2 and Ni 2 Al 3 and an inner layer consisting of Ni 2 Al 3 was formed. This coating layer contained about 2 at% Cr. The cyclic oxidation test showed that for the sample with a coating consisting of Ni aluminide without Pt, a mass reduction due to spallation of an oxide scale took place during the oxidation test, whereas for the sample with a coating consisting of Ni aluminide containing Pt, no mass reduction took place. For the sample with a coating consisting of Ni aluminide containing Pt after the oxidation test, the formation of an adhesive Al 2 O 3 scale was observed. The cyclic oxidation test also showed that for the sample with a coating consisting of Ni aluminide containing Pt formed on a pure Ni substrate, a large mass increase took place during the oxidation test, while for the sample with the coating formed on the Ni-6 at% Cr alloy substrate, such a mass increase did not take place. Such effects of Pt in the coating and 6 at% Cr in the alloy substrate on the cyclic oxidation resistance are discussed from the viewpoint of the formation of a protective Al 2 O 3 scale.

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Examination of the platinum effect on the oxidation behavior of nickel-aluminide coatings

Cited by 97 publications

References 13 publications

Sulfur Segregation at Al2O3/γ-Νi + γ′-Ni3Al Interfaces: Effects of Pt, Cr and Hf Additions

Sulfur Segregation at Al2O3/γ-Νi + γ′-Ni3Al Interfaces: Effects of Pt, Cr and Hf Additions

Characterization of Sulfur Distribution in Ni-Based Superalloy and Thermal Barrier Coatings After High Temperature Oxidation: A SIMS Analysis

Preparation of Ni-Al-Pt Coating on Ni-6 at%Cr Alloy by Electrodeposition Method and Cyclic-Oxidation Resistance

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