Effect of Y Distribution on the Oxidation Kinetics of NiCoCrAlY Bond Coat Alloys

Nijdam, T.J.; Sloof, Willem G.

doi:10.1007/s11085-007-9080-z

Cited by 64 publications

(42 citation statements)

References 32 publications

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“…Y can also affect the growth rate of alumina scales. According to some published work, if large Y-oxides form in the alumina scale, the growth rate of the alumina scale will increase due to an increase of the inward diffusion of oxygen along grain boundaries [67][68][69]. However, if no large Y-oxides form, doping some yttrium in the alumina scale can decrease the grain-boundary diffusion of cations, resulting in a slower oxidation rate [70,71].…”

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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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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“…The process is slower for yttrium, but in due course it too will be depleted from the alloy, as also shown recently for NiCoCrAlY coatings. [21] Zirconia precipitate morphologies change with temperature, from elongated, threadlike structures at 1473 K (1200°C) to approximately spheroidal shapes at 1573 K (1300°C). These shapes reflect different outcomes in the competition between the nucleation and growth processes leading to precipitate formation.…”

Section: A Fecraly+zr Oxidation In Ar-omentioning

confidence: 99%

“…[21] expresses the requirement for kinetic stability of the three-phase Al 2 O 3 -ZrO 2 -alloy interface. Activation energies, E A , for the different diffusion processes are summarized in Table V.…”

Section: A Fecraly+zr Oxidation In Ar-omentioning

confidence: 99%

Effect of Zr Additions on the Oxidation Kinetics of FeCrAlY Alloys in Low and High pO2 Gases

Young

Naumenko

Wessel

et al. 2010

Metall Mater Trans A

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Alloys of nominal composition Fe-20Cr-5Al-0.05Y (mass pct) with and without a 0.03 pct Zr addition were isothermally oxidized at temperatures of 1473 to 1573 K (1200 to 1300°C) in both flowing Ar-O 2 and Ar-H 2 -H 2 O. Continuous thermogravimetric (TG) measurements of oxygen uptake showed the rates to be faster in both gases for Zr-containing than for the Zr-free alloy. Scale growth on the Zr-bearing alloy by inward oxygen diffusion is accelerated by the fine alumina grain size and the formation of elongated zirconia particles in the two-phase scales. Zirconia formation ceases when the supply of metal in the thin alloy substrate is exhausted, and subsequent single-phase alumina growth proceeds at a slower rate. A simple diffusion model is shown to account semiquantitatively for zirconium enrichment in alumina scales. The presence of hydrogen modifies both oxygen transport in the scale and its permeability in the alloy.

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“…Co, Ni, Cr and Al are added in various amounts so that the microstructure of the coating can be tailored to meet specific requirements. Minor elements, such as Y, are also introduced to improve the oxidation resistance [6,7]. Generally MCrAlY alloys are multi-phase materials and can comprise, for example, fcc γ-Ni, bcc β-NiAl and/or γʹ (Ni 3 Al) phases, depending on the compositions used [8].…”

Section: Introductionmentioning

confidence: 99%

Some aspects on modelling of the β-phase depletion behaviour under different oxide growth kinetics in HVOF CoNiCrAlY coatings

Chen

McCartney

2017

Surface and Coatings Technology

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In this paper, β-phase depletion behaviour of free-standing high velocity oxy-fuel (HVOF) thermally sprayed CoNiCrAlY coatings was studied. Microstructural analysis showed a twophase microstructure of γ-Ni matrix and β-NiAl secondary phase after heat treatment. Fine grains were found around the sprayed particle boundaries and coarse grains were retained as the original particle structure, with grain sizes varying from 2 to 0.5 µm or even less for both phases. The β-phase depletion behaviour was investigated during isothermal oxidation and was also modelled through diffusion calculations. A previously developed β-phase depletion model was utilised to study the evolution of β-phase depletion under different oxide growth kinetics. Three oxide growth models were tried: 1) Meier model, 2) thermogravimetric analysis (TGA) model, and 3) experimentally fitted oxide growth model. The oxide growth kinetics were converted to Al flux functions which were used as the boundary conditions in the DICTRA modelling. It is shown that the results obtained from the three models exhibit good agreements between the measured and predicted results for times up to 100 h at 1100 C, but discrepancies were noted at longer oxidation times. Further improvements on closely 2 modelling the oxidation kinetics and the effective diffusion behaviour are needed to minimise the discrepancies at longer oxidation times.

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Effect of Y Distribution on the Oxidation Kinetics of NiCoCrAlY Bond Coat Alloys

Cited by 64 publications

References 32 publications

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

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

Effect of Zr Additions on the Oxidation Kinetics of FeCrAlY Alloys in Low and High pO2 Gases

Some aspects on modelling of the β-phase depletion behaviour under different oxide growth kinetics in HVOF CoNiCrAlY coatings

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