Effect of Chemical Compositions and Surface Morphologies of MCrAlY Coating on Its Isothermal Oxidation Behavior

Li, Yong; Li, Chang‐Jiu; Zhang, Qiang; Xing, Lu-Kuo

doi:10.1007/s11666-010-9590-0

Cited by 38 publications

(15 citation statements)

References 43 publications

(43 reference statements)

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“…A certain level of surface roughness is desired in the production of coating. A number of studies are available in the literature regarding the effect of surface roughness on TBC formation [10,[28][29][30][31][32][33][34]. According to literature, surface treatments like shot peening, grit blasting and polishing are used to decrease surface roughness for TBC systems.…”

Section: As-deposited Coating Characterizationmentioning

confidence: 99%

Effect of shot peening on the oxidation behavior of thermal barrier coatings

Karaoğlanlı

Döleker

Demirel

et al. 2015

Applied Surface Science

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Section: As-deposited Coating Characterizationmentioning

confidence: 99%

Effect of shot peening on the oxidation behavior of thermal barrier coatings

Karaoğlanlı

Döleker

Demirel

et al. 2015

Applied Surface Science

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“…MCrAlY coatings exhibit their protective effect owing to the fact that aluminium forms a continuous oxide layer, predominantly alumina, on the coating surface [9][10][11][12]. The aluminium consumed by forming the protective oxides is mainly from the Al-rich β phase which acts as the Al reservoir in the coating.…”

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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“…For instance, cold sprayed MCrAlY coatings show a lower β phase depletion rate during oxidation compared with that of LPPS sprayed coatings due to different element distribution and surface roughness [102].…”

Section: Role Of Deposition Techniquesmentioning

confidence: 99%

Asset Liability Management for Tanzania Pension Funds

Zhang

2018

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Linköping 2018Front page images: (1) low magnification of snowflake like α-Al 2 O 3 formed on polished coating surface after 10 h oxidation; (2) blade-like transient Al 2 O 3 formed on shot-peened coating surface after 100 min oxidation; (3) spinel island formed on polished coating surface after 10 min oxidation. AbstractMCrAlY coatings (M=Ni and/or Co) have been widely used for the protection of superalloy components against oxidation and hot corrosion in the hot sections of gas turbines. The drive to improve engine combustion efficiency while reducing emissions by increasing the operation temperature brings a big challenge for coating design. As a result, the need for improvement of MCrAlY coatings for better oxidation resistance is essential.Formation of a stable, dense, continuous, and slow-growing α-Al 2 O 3 layer, on the MCrAlY coating surface, is the key to oxidation protection, since the protective α-Al 2 O 3 scale offers superior oxidation resistance due to its lower oxygen-diffusion rate as compared with other oxides. The ability of a MCrAlY coating to form and maintain such a protective scale depends on the coating composition and microstructure, and can be improved through optimization of deposition parameters, modification of coating surface conditions, and so on. Part of this thesis work focuses on studying the effect of post-deposition surface treatments on the oxidation behavior of MCrAlX coatings (X can be yttrium and/or other minor alloying elements). The aim is to gain fundamental understanding of alumina scale evolution during oxidation which is important for achieving improved oxidation resistance of MCrAlX coatings. Oxide scale formed on coatings at initial oxidation stage and the effect of surface treatment were investigated by a multi-approach study combining photo-stimulated luminescence, microstructural observation and weight gain. AcknowledgementsThe present project is financed by Siemens Industrial Turbomachinery AB, Swedish Energy Agency through KME consortium -ELFORSK, and are therefore grateful

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Effect of Chemical Compositions and Surface Morphologies of MCrAlY Coating on Its Isothermal Oxidation Behavior

Cited by 38 publications

References 43 publications

Effect of shot peening on the oxidation behavior of thermal barrier coatings

Effect of shot peening on the oxidation behavior of thermal barrier coatings

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

Asset Liability Management for Tanzania Pension Funds

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