Composite coatings of CoCrAlY plus platinum

Lowrie, R.S.; Boone, D.H.

doi:10.1016/0040-6090(77)90236-x

Cited by 42 publications

(20 citation statements)

References 2 publications

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“…This improves oxidation and corrosion resistance [13,[19][20][21][22][23][24][25]. As previously mentioned, under oxidation conditions, MCrAlY coatings are known for forming alumina but also other oxides, among them RE-rich oxides.…”

Section: Introductionmentioning

confidence: 99%

Beneficial Effect of Pt and of Pre-Oxidation on the Oxidation Behaviour of an NiCoCrAlYTa Bond-Coating for Thermal Barrier Coating Systems

et al. 2011

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The oxidation behaviour of a thermal barrier coating (TBC) system is a major concern as the growth of the thermally grown oxide (TGO) layer on the bondcoating creates stresses that greatly favour the thermal barrier spallation. To delay the loss of the thermal protection provided, research has focused on the bondcoating composition and microstructure as well as on the parameters required for a suitable pre-oxidation treatment before the deposition of the ceramic top coat. Platinum is known to enhance the oxidation/corrosion resistance of MCrAlY coatings. The effect of Pt on the oxidation behaviour of a NiCoCrAlYTa coating was assessed in this study. In addition, pre-oxidation treatments were conducted to determine if the oxidation behaviour of the modified NiCoCrAlYTa coating could be further improved.

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Section: Introductionmentioning

confidence: 99%

Beneficial Effect of Pt and of Pre-Oxidation on the Oxidation Behaviour of an NiCoCrAlYTa Bond-Coating for Thermal Barrier Coating Systems

et al. 2011

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“…In fact, the oxidation performance of commercial aluminide coatings has been enhanced by platinum additions during the last 30 years [7], but the mechanism of the Pt effect are still unknown. While the high sulphur affinity of a reactive element may prevent sulphur segregation to the oxide/metal interface and the associated decrease of strength [8], the same is not expected for Pt, because the heat of formation for a reactive element sulfide is 3-5 times greater than that of Pt sulfide, and Pt sulfide is even less stable than Al sulfide [9,10].…”

Section: Introductionmentioning

confidence: 99%

The wetting behavior of NiAl and NiPtAl on polycrystalline alumina

et al. 2007

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In order to understand the beneficial effect of Pt on the adherence of thermally grown alumina scales, sessile drop experiments were performed to study the wetting of poly-crystalline alumina by nickel-aluminum alloys with or without platinum addition where the amount of Pt ranged from 2.4 to 10 at.%. Subsequent interfacial structure was evaluated using atomic force microscopy. Platinum addition enhances the wettability of NiAl alloys on alumina, reduces the oxide/alloy interface energy and increases the interfacial mass transport rates.

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“…The measurement of the DBTT is as shown in Fig. 7a proposed by Lowrie [69] who suggested DBTT is the temperature above which a minimal plastic strain of 0.6% should be obtained in a tensile test. There are also other definitions of DBTT [70].…”

Section: Creepmentioning

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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Composite coatings of CoCrAlY plus platinum

Cited by 42 publications

References 2 publications

Beneficial Effect of Pt and of Pre-Oxidation on the Oxidation Behaviour of an NiCoCrAlYTa Bond-Coating for Thermal Barrier Coating Systems

Beneficial Effect of Pt and of Pre-Oxidation on the Oxidation Behaviour of an NiCoCrAlYTa Bond-Coating for Thermal Barrier Coating Systems

The wetting behavior of NiAl and NiPtAl on polycrystalline alumina

Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments

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