Synthesis and oxidation behavior of platinum-enriched γ+γ′ bond coatings on Ni-based superalloys

Zhang, Y.; Ballard, Donna; Stacy, Justin; Pint, Bruce A.; Haynes, J. Allen

doi:10.1016/j.surfcoat.2006.07.245

Cited by 24 publications

(14 citation statements)

References 17 publications

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“…The second stage could be a pack or CVD process to increase the Al, Cr, Hf, etc. content of the coating after Pt-plating [5,7,15,16]. The first γ+γ' coatings [3,4,9,15] made at ORNL/TTUused ~7µm Pt, the same amount as in conventional low activity chemical vapor deposition aluminide coatings [17], and a 2h vacuum anneal at 1150° or 1175°C.…”

Section: Coating Fabricationmentioning

confidence: 99%

“…The first γ+γ' coatings [3,4,9,15] made at ORNL/TTUused ~7µm Pt, the same amount as in conventional low activity chemical vapor deposition aluminide coatings [17], and a 2h vacuum anneal at 1150° or 1175°C. However, these coatings generally showed inferior oxidation resistance to conventional Pt-modified aluminide coatings on the same substrates [4,9,15].…”

Section: Coating Fabricationmentioning

confidence: 99%

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The Performance of Pt-Modified Alumina-Forming Coatings and Model Alloys

Pint¹,

Haynes²,

More³

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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The oxidation behavior of two-phase, γ+γ' Pt diffusion coatings and model alloys has been evaluated to better understand the potential of this class of coatings for power generation applications. Coatings were deposited on both directionallysolidified alloy 142 and single crystal N5 superalloys. Fabrication issues such as initial Pt thickness and annealing temperature were evaluated. Oxidation testing was performed in both dry O 2 and with the addition of H 2 O to study the performance of γ+γ' and conventional coating materials. After exposure for 1000, 1-h cycles at 1150°C in dry O 2 , a γ+γ' coating on N5 had evolved into a thicker, almost continuous γ' layer with the Pt content dropping to ~7at.% in this layer and diffusing ~250 µm into the substrate, disrupting the γ+γ' substrate microstructure. Characterization of the oxide formed on a γ+γ' composition showed that even 30 at.%Pt did not prevent the formation of a Ni-rich spinel layer at 1200°C. In order to assist the coating development process, model alloys also were evaluated. Other Pt group metals (Pd and Ir) were evaluated as well as the addition of Cr and various Hf levels. As expected, Cr and Hf were beneficial for oxidation resistance. However, Pd was not an adequate replacement for Pt because of the multi-phase microstructure that formed. A γ+γ' composition had a 1000°C yield stress in compression that was significantly higher than γ'-Ni 3 Al or β-NiAl. Also, the thermal expansion coefficient was very similar to other Ni-Al alumina-formers. The performance of γ+γ' compositions are very promising, however, sensitivity to superalloy substrate composition, Pt interdiffusion during long-term service, spinel formation and the potential need for a secondary processing step are areas of concern for this class of coatings.

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Section: Coating Fabricationmentioning

confidence: 99%

Section: Coating Fabricationmentioning

confidence: 99%

The Performance of Pt-Modified Alumina-Forming Coatings and Model Alloys

Pint¹,

Haynes²,

More³

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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“…Recent research on the oxidation and rumpling properties of Pt-containing g+g 0 bond coats has shown that this phase combination is also resistant to rumpling deformation at the expense of slightly faster oxidation rate than the b-phase (Ni,Pt)Al coatings [44][45][46]. These experiments were performed at 1150 C on two-phase coatings that were in the Al-rich side of the g+g 0 phase field.…”

Section: Comparison To Pt-modified G+g 0 Coatingsmentioning

confidence: 99%

Bond coatings with high rumpling resistance: Design and characterization

Jorgensen

Suzuki

Lipkin

et al. 2016

Surface and Coatings Technology

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The behavior of two new high-strength g 0 Ni 3 Al-base bond coats have been compared to a baseline b (Pt,Ni)Al bond coat via thermal cycling to a maximum temperature of 1204 C. The rumpling amplitude of the g 0 coating is significantly lower than the (Pt,Ni)Al as characterized by a nondestructive optical profilometry technique. The g 0 coatings resist rumpling and spallation of the thermally grown oxide in spite of faster oxidation compared to Pt-modified NiAl.

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“…Moreover, many papers were devoted to elemental segregation and the effect of reactive elements (RE), such as Y, Hf, and Zr, on the overall stability of the TGO . Extensive studies by Pint showed that when properly doped REs reduce the growth rate of Al 2 O 3 and simultaneously the extent of vacancy injection into the scale.…”

Section: Introductionmentioning

confidence: 99%

Microstructural examination of TGO formed during pre‐oxidation on Pt‐aluminized Ni‐based superalloy

Swadźba

Wiedermann

Hetmańczyk

et al. 2013

Materials & Corrosion

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The study concerns electron beam physical deposition (EB-PVD) of yttria stabilized zirconia (YSZ) deposited on pre-oxidized Pt-modified aluminide bond coating. The coating was prepared by the means of Pt galvanizing followed by vapor phase aluminizing at 1050 8C. During annealing at 1100 8C in air atmosphere for 4 h a 1 µm thick layer of thermally grown oxide (TGO) consisting of equiaxed a-alumina grains was formed. Focused ion beam and scanning/ transmission electron microscopy analysis revealed the presence of nanoscale Cr-rich precipitates distributed in the TGO as well as Cr precipitation in the grain boundaries of the b phase at the interface between the TGO and bond coat. Deposition of the YSZ on a pre-oxidized substrate provided mechanical keying with the TGO. Void formation was observed at the TGO and bondcoat interface presumably due to initial transient alumina formation.

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Synthesis and oxidation behavior of platinum-enriched γ+γ′ bond coatings on Ni-based superalloys

Cited by 24 publications

References 17 publications

The Performance of Pt-Modified Alumina-Forming Coatings and Model Alloys

The Performance of Pt-Modified Alumina-Forming Coatings and Model Alloys

Bond coatings with high rumpling resistance: Design and characterization

Microstructural examination of TGO formed during pre‐oxidation on Pt‐aluminized Ni‐based superalloy

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