Degradation of Advanced MCrAIY Coatings by Oxidation and Interdiffusion

Anton, Reiner; Birkner, J.; Czech, N.; Werner, Stefan

doi:10.4028/www.scientific.net/msf.369-372.719

Cited by 13 publications

(15 citation statements)

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“…The removal of Al from the coating results in the dissolution of the β-phase, thus giving rise to β-depleted zones at the coating surface, due to oxidation, and at the coating-substrate interface, due to interdiffusion [6,15,16]. When the β-phase is completely depleted, or when the Al concentration reaches a critically low value, the coating can no longer work as an Al reservoir and less-protective oxides forms [2,6,13,[15][16][17]; the depletion of aluminum thus marks the end of the useful life of the coating [3].…”

Section: Introductionmentioning

confidence: 99%

“…When the β-phase is completely depleted, or when the Al concentration reaches a critically low value, the coating can no longer work as an Al reservoir and less-protective oxides forms [2,6,13,[15][16][17]; the depletion of aluminum thus marks the end of the useful life of the coating [3]. The modeling and prediction of Al depletion through mechanisms of oxidation and interdiffusion thus becomes important for 1) the durability assessment of existing coatings, 2) establishing of appropriate substrate/coating couples, and 3) the development of new coating alloys.…”

Section: Introductionmentioning

confidence: 99%

“…As oxidation resistance is achieved by the formation of alumina, the useful life of the coating is often determined by the Al depletion that occurs through oxidation and interdiffusion [3,5,6,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

“…Hence, the need arises for protective coatings which ensure the formation of a protective oxide layer and act as an Al reservoir so that alumina can be reformed would it crack and spall due to thermal cycling [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

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Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Yuan

Eriksson

Peng

et al. 2013

Surface and Coatings Technology

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MCrAlY coatings are deposited onto superalloys to provide oxidation and corrosion protection at high temperature by the formation of a thermally grown oxide scale. In this project, the oxidation behaviour of a HVOF CoNiCrAlYSi coating on IN792 was studied for both isothermal oxidation (900, 1000 and 1100 °C) and thermal cycling (100-1100 °C). The microstructural evolution of the CoNiCrAlYSi coatings after oxidation was investigated. It was found that the Al-rich β phase is gradually consumed due to two effects: surface oxidation and coating-substrate interdiffusion. Some voids and oxides along the coating-substrate interface, or inside the coating, were considered to play a role in blocking the diffusion of alloying elements. Based on the microstructural observation, an oxidation-diffusion model, considering both surface oxidation and coating-substrate interdiffusion, was developed by using Matlab and DICTRA software to predict the useful life of MCrAlY coatings.A new concept of diffusion blocking is also introduced into the model to give more accurate description on the microstructural evolution. The results from modeling and the experimentally established composition profiles showed good agreement.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Yuan

Eriksson

Peng

et al. 2013

Surface and Coatings Technology

View full text Add to dashboard Cite

show abstract

“…When the Al content in the coating is lower than a critical level, the coating will be incapable to support the growth and the maintenance of the alumina scale, and then other oxides like NiO, CoO, and/or spinels will aggressively form which usually can not form a dense and protective scale like alumina for oxidation resistance [7,[45][46][47][48][49]. In this case, the coating will deteriorate rapidly to fail.…”

Section: Oxidationmentioning

confidence: 99%

Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments

Yuan¹

2014

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after a high-temperature oxidation (the image height is 191 μm). Back: The profiles of alloying elements in a MCrAlY coating-superalloy system after a high-temperature oxidation (the solid curves are simulation results, and the dots are experimental ones).Printed by: LiU-Tryck, Linköping, Sweden, 2014 ISBN: 978-91-7519-247-5 ISSN 0345-7524 Distributed by: Linköping University Department of Management and Engineering SE-581 83, Linköping, Sweden © 2014 Kang YuanNo part of this publication may be reproduced or transmitted in any form without prior permission of the author.iii Abstract MCrAlY coatings ("M" for Ni and/or Co) are widely used for the protection of superalloy components operated at high temperatures such as in the hot sections of gas turbines. The exposure to high temperature can cause coating degradation due to oxidation or hot corrosion at the coating surface. Microstructures in the coating and the coating life are affected also by the diffusion of alloying elements through the coating-superalloy interface. This PhD project, by applying thermodynamic modelling and experimental tests, investigates the oxidation and hot corrosion behavior of new MCrAlX coatings, in which X, referring to minor elements, is used to highlight the functions of such elements.In order to understand and predict the coating degradation progress during thermal exposure, an oxidation-diffusion model has been established for MCrAlX coating-superalloy systems, which integrates the oxidation of aluminum at coating surface, diffusion of alloying elements, and the diffusion-blocking effect in the materials. The predicted chemical composition profile and microstructure agreed well with experimental results in a CoNiCrAlYSiTa-Inconel 792 system. The model was further applied in several coating-superalloy systems to study the influence of coating composition, superalloy composition and temperature on the evolution of microstructure in the coating and the coating life. The results have demonstrated the potential of the model in designing new durable MCrAlX coatings. In addition to the applications in coating-superalloy systems, the model was also adapted for studying the microstructural development in a superalloy in which internal oxidation and nitridation occurred in an oxidation process.The oxidation behavior of some HVOF MCrAlX coatings was studied by thermal exposure at different temperatures (900, 1000, 1100 °C). Different spinels formed above the alumina scale, depending on the oxidation temperature. The minor alloying elements, Ru and Ir, had no direct influence on the oxidation behavior but may affect the phase stability in the coating.MCrAlX coatings were also tested in 48-hour cycles at 900 °C in different hot corrosion environments containing sulphates and/or SO 2 . The results showed that the coating performance was dependent on coating quality, concentration of Al and Cr in the coating, and the hot corrosion condition. It was also found that the addition of SO 2 in the environment may not necessarily be bad for hot cor...

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Effect of Particle Size Distribution on Isothermal Oxidation Characteristics of Plasma Sprayed CoNi- and CoCrAlY Coatings

et al. 2007

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The effect of particle size distribution on the degradation behavior of plasma sprayed CoNi-and CoCrAlY coatings during isothermal oxidation was investigated, in terms of the oxygen content, porosity, surface roughness, and oxide scale formation. The results show that the degradation of both coatings was considerably influenced by the starting particle size distribution. It also shows that in the assprayed vacuum plasma spray (VPS) coatings the oxygen content on the coating surface increased significantly with decreased average particle size. But after thermal exposure, the difference of the oxygen contents between the coatings with different particle size was decreased. The powder with various particle size resulted in low porosity inside the coatings during the deposition process. The surface roughness of the coatings increased with increased particle size. The small particles produced a relatively smooth surface, and the oxide growth in the coating deposited by small particle was slower than that in the large particle coating.

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Degradation of Advanced MCrAIY Coatings by Oxidation and Interdiffusion

Cited by 13 publications

References 0 publications

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Modeling of microstructural evolution and lifetime prediction of MCrAlY coatings on nickel based superalloys during high temperature oxidation

Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments

Effect of Particle Size Distribution on Isothermal Oxidation Characteristics of Plasma Sprayed CoNi- and CoCrAlY Coatings

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