A relationship between indigenous impurity elements and protective oxide scale adherence characteristics

Smeggil, J. G.; Funkenbusch, A. W.; Bornstein, N. S.

doi:10.1007/bf02661258

Cited by 266 publications

(60 citation statements)

References 20 publications

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“…As reported for other alloy systems such as Pt modified -0 coatings and Pt modified aluminide coatings, [14][15][16][17][18] these results indicate that trace amount of Hf addition into Pt-Ir alloy coatings played a roll in suppressing surface rumpling and void formation, resulting in the enhanced oxidation resistance. On the other hand, under thermal cycles Hf-free coatings are more prone to form undulated surfaces.…”

Section: Oxidation Resistancesupporting

confidence: 78%

“…[11][12][13] On the other hand, proper addition of reactive elements such as Zr, Y, Hf to bond-coat is reported to minimize the detrimental effect of S and to enhance the scale adhesion. [14][15][16][17][18] Among them, Hf addition is of particular interest because it is known to reduce the scale growth rate and thus effective in enhancing oxidation resistance.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Hf Addition on Oxidation Properties of Pt-Ir Modified Aluminide Coating

et al. 2007

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In the present study, the effect of Hf addition on oxidation kinetics of Pt-Ir modified aluminide coatings was investigated. Pt-15 at%Ir and Pt-15 at%Ir with trace amount of Hf films with 7$8 mm thick were deposited on a Ni-based single crystal superalloy TMS-82+ using magnetron sputtering, followed by a diffusion treatment and conventional Al pack cementation. While there were no significant microstructual differences observed in as aluminized specimens, cyclic oxidation test at 1423 K revealed clear advantages of Hf addition. Hf containing coatings showed smaller mass change with retarded surface rumpling during cyclic oxidation test. These results confirmed the beneficial effects of Hf addition reported for other alloy systems such as Pt modified -0 coatings and Pt modified aluminide coatings.

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Section: Oxidation Resistancesupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Effect of Hf Addition on Oxidation Properties of Pt-Ir Modified Aluminide Coating

et al. 2007

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“…[2,13] One issue that requires further study is the interaction between Pt and S. Understanding this mechanism may provide useful insight into the role of S in high temperature oxidation. [33,34] The incorporation of Hf into aluminide coatings offers significant improvements in performance and could preclude the use of Pt. The 0.05Hf level used in this study is sufficient to be uniformly included in the alloy while avoiding excessive internal oxidation associated with higher Hf contents.…”

Section: Discussionmentioning

confidence: 99%

Compositional Effects on Aluminide Oxidation Performance: Objectives for Improved Bond Coats

Pint¹,

Haynes²,

More³

et al. 2000

Superalloys 2000 (Ninth International Symposium)

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In order to achieve long thermal barrier coating lifetimes, underlying metallic bond coats need to form adherent, slowgrowing A l 2 O 3 layers. A set of guidelines for developing aluminide bond coat compositions is proposed in order to maximize oxidation performance, i.e. forming a slow-growing adherent alumina scale. These criteria are based on results from cast, model alloy compositions and coatings made in a laboratoryscale chemical vapor deposition facility. Aluminide coatings are thought to have more long-range potential because of their lower coefficient of thermal expansion compared to MCrAlYs. The role of Pt in improving alumina scale adhesion and countering the detrimental role of indigenous sulfur is discussed. However, the improvements associated with Pt are minimal compared to reactive element doping. One strategy which has great promise for improvement is to incorporate Hf into the coating. From an oxidation standpoint, this would preclude the need for Pt in the coating and also reduce the scale growth rate. While excellent oxidation performance was observed for cast Hf-doped NiAl, its benefits can be compromised and even eliminated by co-doping with elements such as Cr,Ti, Ta and Re. Creating a pure Hf-doped NiAl is one promising approach for improving the oxidation performance of bond coats.

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“…Y is added in MCrAlY coatings mainly for improving the adhesion of alumina scales [65,66]. Y can also affect the growth rate of alumina scales.…”

Section: Surface Oxidationmentioning

confidence: 99%

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

Yuan

Peng

et al. 2015

Surface and Coatings Technology

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Abstract. MCrAlY coatings are widely used to protect superalloys against oxidation and corrosion at high temperature in gas turbine engines. To design a durable MCrAlY coating, the behaviour of alloying elements in coating-superalloy system needs to be better understood. After oxidation tests in temperature range between 900 °C to 1100 °C, the development of the microstructures in the samples was analysed at the coating surface or in areas near the coatingsuperalloy interface. Some interdiffusion simulations were also done to model the diffusion behaviour of alloying elements in different coating-superalloy couples. The results show that both oxidation at the coatings' surface and the elements' diffusion inside of the materials were temperature-and chemical-composition dependent. The behaviour of some minor elements like Y, Hf, Ru and Ir in the oxidation processes was particularly studied by tracking their position and composition in the materials.

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A relationship between indigenous impurity elements and protective oxide scale adherence characteristics

Cited by 266 publications

References 20 publications

Effect of Hf Addition on Oxidation Properties of Pt-Ir Modified Aluminide Coating

Effect of Hf Addition on Oxidation Properties of Pt-Ir Modified Aluminide Coating

Compositional Effects on Aluminide Oxidation Performance: Objectives for Improved Bond Coats

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

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