Coatings for blade and vane applications in gas turbines

Rhys-Jones, T.N.

doi:10.1016/0010-938x(89)90104-2

Cited by 150 publications

(46 citation statements)

References 9 publications

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“…The excellent oxidation resistance of NiAI-based materials is well known and has been exploited for many years in the form of coatings for Ni-base superalloys (Rhys-Jones 1989;Wood and Goldman 1987). The oxidation resistance of NiAI alloys is due to the easy formation and slow growth rate of protective Al 2O3 scales.…”

Section: Environmental Resistancementioning

confidence: 99%

The Physical and Mechanical Metallurgy of NiAl

Noebe¹,

Bowman²,

Nathal³

1996

Physical Metallurgy and Processing of Intermetallic Compounds

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Section: Environmental Resistancementioning

confidence: 99%

The Physical and Mechanical Metallurgy of NiAl

Noebe¹,

Bowman²,

Nathal³

1996

Physical Metallurgy and Processing of Intermetallic Compounds

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“…Several techniques have been employed to deposit NiAl coatings [15]. Two of them are: the electron beam physical vapor deposition (EB-PVD) [16,17] and the chemical vapor deposition (CVD) methods [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Zirconium Modified Aluminide Coatings Obtained by the CVD and PVD Methods

Romanowska¹,

Zagula-Yavorska

Sieniawski³

et al. 2013

OJMetal

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The paper presents the comparison of the structures of the zirconium modified aluminide coatings deposited on pure nickel by the CVD and PVD methods. In the CVD process, zirconium was deposited from the ZrCl 3 gas phase at the 1000˚C. Zirconium thin layer (1 or 7 μm thick) and aluminum thin layer (1.0, 0.7 or 0.5 μm thick) were deposited by the EB-PVD method. Deposition velocity was about 1 m/min. The layers obtained by the Electron Beam Evaporation method were subjected to diffusion treatment for 2 h in the argon atmosphere. The obtained coatings were examined by the use of an optical microscope (microstructure and coating thickness) a scanning electron microscope (chemical composition on the cross-section of the modified aluminide coating) and XRD phase analysis. Microstructures and phase compositions of coatings obtained by different methods differ significantly. NiAl(Zr), Ni 3 Al and Ni(Al) phases were found in the CVD aluminide coatings, whereas Ni 5 Zr, Ni 7 Zr 2 and γNi(Al,Zr) were observed in coatings obtained by the PVD method. The results indicate that the microstructure of the coating is strongly influenced by the method of manufacturing.

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“…There are also other definitions of DBTT [70]. DBTT for some NiCrAl and CoCrAl alloys [6,19] are shown in Fig. 7b, in which different DBTT definitions may be adapted for those alloys.…”

Section: Creepmentioning

confidence: 99%

“…Table 3. Desirable coating requirements for coating-superalloy systems in gas turbines (mainly based on the summarizations by [8,19] Diffusion coatings are produced by a process with the enrichment of one or several elements at the surface of a substrate material [6]. For instance, aluminide diffusion coating (NiAl) is produced by the surface enrichment of Al-rich species followed by an inward diffusion of Al or outward diffusion of Ni; diffusion direction is dependent upon the Al activity during the aluminizing process.…”

Section: High-temperature Coatingsmentioning

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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Coatings for blade and vane applications in gas turbines

Cited by 150 publications

References 9 publications

The Physical and Mechanical Metallurgy of NiAl

The Physical and Mechanical Metallurgy of NiAl

Zirconium Modified Aluminide Coatings Obtained by the CVD and PVD Methods

Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments

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