Effect of Polishing Treatment on Rumpling of Oxide Scales on NiPtAl Coatings with Different Pt-Content

2013 ◽  
Vol 662 ◽  
pp. 383-386
Author(s):  
Peng Song ◽  
Jian Sheng Lu
Keyword(s):  
High Temperature ◽  
Nickel Aluminide ◽  
Aluminide Coating ◽  
Temperature Cycling ◽  
Oxide Surface ◽  
Temperature Oxidation ◽  
Aluminide Coatings ◽  
Temperature Exposure ◽  
Engine Components ◽  
Surface Morphologies

Pt-modified nickel aluminide coatings have been more widely used for protection of jet-engine components against high-temperature oxidation. The coating rumpling of two Pt-content NiPtAl coatings was studied in this paper during high temperature exposure. The results indicated that the NiPtAl coating grains size made a great contribution to the oxide surface morphologies, especially rumpling. Smaller grain size within high-Pt coating indicated a denser rumpling compared to low-Pt coating due to PtAl2 formation in the earlier coating. The failed local alumina at the ridges was also found on the low-Pt coating after cyclic oxidatioin. It was found that polished treatment resulted a comparatively flat and homogeneous oxide layer compared to as-received coatings. The temperature cycling could promote the aluminide coating rumpling, however, the polished treatment could not completely eliminate the roughening.

Increase in ductility of Pt-modified nickel aluminide coating with high temperature ageing

2016 ◽  
Vol 105 ◽  
pp. 505-518 ◽  
Author(s):  
Vladimir A. Esin ◽  
Vincent Maurel ◽  
Paul Breton ◽  
Alain Köster ◽  
Serge Selezneff
Keyword(s):  
High Temperature ◽  
Nickel Aluminide ◽  
Aluminide Coating ◽  
Temperature Ageing

High Temperature Resistance of Selected HVOF Coatings

2015 ◽  
Vol 662 ◽  
pp. 111-114 ◽  
Author(s):  
Šárka Houdková ◽  
Jan Černý ◽  
Zdeněk Pala ◽  
Petr Haušild
Keyword(s):  
High Temperature ◽  
Thermal Spraying ◽  
High Velocity Oxygen Fuel ◽  
Temperature Oxidation ◽  
Ni Alloys ◽  
The Stability ◽  
Temperature Exposure ◽  
Oxygen Fuel ◽  
Hardness Values ◽  
Composition Changes

The HVOF (high velocity oxygen fuel) thermal spraying technology is widely used for creation of coatings notable for their resistance against various kinds of loading. Depending on the sprayed material, the coatings suitable for high temperature applications can be sprayed as well. The coatings, based on CrC or Co/Ni alloys, offer the advantageous combination of high temperature oxidation resistance and the wear resistance. In the paper, the attention is paid to the evaluation of the influence of the high temperature on the coatings microstructure and mechanical properties, namely hardness. The stability of the hardness values in respect to the time of the high temperature exposure is presented and related to the phase composition changes.

Effect of Hf Addition on High Temperature Properties of Ir-Containing Alloy Coatings

2007 ◽  
Vol 546-549 ◽  
pp. 1689-1694 ◽  
Author(s):  
Hideyuki Murakami ◽  
K. Kamiya ◽  
Akihiro Yamaguchi ◽  
Ying Na Wu ◽  
Seiji Kuroda
Keyword(s):  
High Temperature ◽  
Cyclic Oxidation ◽  
Flat Surface ◽  
Small Difference ◽  
Aluminide Coating ◽  
High Temperature Properties ◽  
Aluminide Coatings ◽  
Cyclic Oxidation Test ◽  
Hf Addition ◽  
Pack Cementation Process

In the present study, high temperature properties of Ir-modified and Ir-Hf-modified aluminide coatings on Ni-based single crystal superalloy TMS-82+ were discussed. They were prepared by depositing pure Ir and Ir-Hf alloys on TMS-82+ using magnetron sputtering and EB-PVD, followed by a conventional Al-pack cementation process. The effects of Hf addition on the oxidation resistance and top-coat spallation resistance were investigated. Cyclic oxidation test at 1423K for 1h as one heating cycle revealed that while there is a small difference in oxidation kinetics and spallation lives between Ir and Ir-Hf coatings, drastic difference in surface morphology was observed. After 50 oxidation cycles the Ir-modified aluminide coating showed surface rumpling whereas the Ir-Hf modified aluminide coatings kept the flat surface. It was also revealed that excessive addition of Hf promoted the internal oxidation, resulting in the deterioration of substrates. These results agree with the conventional Pt-modified aluminide coatings and Ni-Al-Hf alloys.

Microstructure Features of Cold-Sprayed NiCoCrAlTaY Coating and its High Temperature Oxidation Behavior

2011 ◽  
Vol 686 ◽  
pp. 595-602 ◽  
Author(s):  
Chang Jiu Li ◽  
Yong Li ◽  
Lu Kuo Xing ◽  
Guan Jun Yang ◽  
Cheng Xin Li
Keyword(s):  
High Temperature ◽  
Oxidation Behavior ◽  
Cold Spraying ◽  
Thermal Exposure ◽  
Isothermal Treatment ◽  
Temperature Oxidation ◽  
The Matrix ◽  
High Temperature Oxidation Behavior ◽  
Temperature Exposure ◽  
Sprayed Coating

Superalloy coating was deposited by cold-spraying using a commercial NiCoCrAlTaY powder. The coating microstructure was investigated by scanning electron microscopy and X-ray diffraction to reveal the change of the b-NiAl phase in the as-received powder particle during coating deposition. The oxidation behavior of the cold-sprayed MCrAlY coating and its microstructural evolution during the isothermal treatment were examined. The results show that significant microstructural change occurred to NiCoCrAlTaY superalloy during cold spraying and the thermal exposure. The intensive plastic deformation upon high velocity impact of spray particles results in transformation of b-NiAl to the matrix phase, forming metaltable b-NiAl depletion zones (b-PDZs) which are distributed around the boundaries of deposited particles in the coating. The central part of the deposited particles with limited deformation retained the original phase constitutions of the starting powder. The b-phase with fine grains is re-precipitated uniformly in the areas in b-PDZs in the as-sprayed coating during high temperature exposure. A stable Al2O3 scale was formed on cold-sprayed NiCoCrAlTaY during oxidation possibly due to active b-PDZs on the top surface of the coating.

Effect of Atmosphere Composition on Lifetime and Oxidation Behavior of EB-PVD TBC with NiPtAl Bondcoats

2013 ◽  
Vol 652-654 ◽  
pp. 1822-1825
Author(s):  
Peng Song ◽  
Jian Sheng Lu
Keyword(s):  
Oxide Layer ◽  
Base Alloy ◽  
Layer Growth ◽  
Low Oxygen ◽  
Aluminide Coatings ◽  
Barrier Coating ◽  
Temperature Exposure ◽  
Short Time ◽  
Surface Morphologies ◽  
Tbc Systems

NiPtAl coatings are widely used as bondcoats for thermal barrier coating (TBC) systems during high temperature exposure. Pt modified aluminide coatings on the CMSX-4 Ni-base alloy were oxidized at 1150°C in different atmospheres. Cross-section oxide layer morphologies on the NiPtAl coatings after TBC failure were similar in air with that in air+15%H2O. The surface morphologies of as-received low and high-Pt bondcoats showed great effect on the oxide layer growth and morphologies due to the different compositions within the two bondcoats. The irregular alumina surface on the low-Pt bondcoat was showed due to the slipping of the NiPtAl grains. Raman spectroscopy illustrated that the alumina mainly consisted θ and α-Al2O3during the Ar+20%O2exposure, however, only α-Al2O3could be found in Ar+4%H2+2%H2O during short time exposure. Low oxygen partial pressure of Ar+4%H2+2%H2O perhaps is the reason that spinel and θ-Al2O3can not formed, and directly promotes the α-Al2O3formation.

Influence of Ru, Mo and Ir on the Behavior of Ni-Based MCrAlY Coatings in High Temperature Oxidation

2014 ◽  
Author(s):  
Kang Yuan ◽  
Ru Lin Peng ◽  
Xin-Hai Li ◽  
Sten Johansson ◽  
Yan-Dong Wang
Keyword(s):  
High Temperature ◽  
Microstructural Evolution ◽  
Structure Study ◽  
Micro Structure ◽  
Temperature Oxidation ◽  
Coating Surface ◽  
Mcraly Coating ◽  
Mcraly Coatings ◽  
Oxidation Performance ◽  
Temperature Exposure

To improve the oxidation/corrosion resistance of MCrAlY coatings (M for Ni and/or Co), elements like Y, Si and Ta have been added into the coatings in past decades. In this study the oxidation performance of a Ni-based MCrAlY coating with small proportion of Ru, Mo and/or Ir were investigated after high-temperature exposure. The oxidation tests were carried out at 900°C, 1000°C or 1100°C. The micro structure study showed that the addition of Ru, Mo and/or Ir had significant influence on the oxidation behavior at the coating surface and the microstructural evolution in the material. The microstructural evolution was quantitatively evaluated by measuring the phase degradation of β-NiAl in the coating and γ′-Ni3Al in the substrate of superalloy. Since no oxides of Ru, Mo and Ir were found on the coating surface, it was believed that the effects by those elements were mainly due to their dissolution in the metallic phases in the coatings.

Evolution of Oxide Scales on Aluminide Coatings under Isothermal and Cyclic Conditions

2008 ◽  
Vol 595-598 ◽  
pp. 11-16 ◽  
Author(s):  
B. Bouchaud ◽  
J. Balmain ◽  
F. Pedraza
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Nodule Formation ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
Growth Stresses ◽  
Aluminide Coatings ◽  
Ni3al Phase ◽  
Cycle 24

The oxide scale evolution with high temperature on CVD aluminide coatings deposited on a Directionally Solidified (DS) Ni-base superalloy is studied in this work. High temperature oxidation was carried out at 1100°C in air for 240 h under isothermal conditions and for 10 cycles (1 cycle = 24 h at 1100°C). The morphological and microstructural characterisation of the coatings has been performed using optical and electron microscopy as well as X-ray diffraction. Contrary to most of the results published in the literature, the rumpling phenomenon appears on the isothermally oxidised specimens whereas spallation, nodule formation and wrinkling of the oxide scale occur on the cyclically oxidised samples. The results are discussed in terms of the β-NiAl to γ’-Ni3Al phase transformation, the likely associated volume changes and of the growth stresses at high temperature.

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