High-Temperature Oxidation and Hot Corrosion Studies on NiCrAlY Coatings Deposited by Flame-Spray Technique

Rana, Nidhi; Mahapatra, Manas Mohan; Jayaganthan, R.; Prakash, S.

doi:10.1007/s11666-015-0237-z

Cited by 30 publications

(10 citation statements)

References 32 publications

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“…The phases identified in feedstock powders and their quantities are summarized in Table 4. γ-Ni,Cr, γ'-Ni 3 Al and β-AlNi were found in Amdry 510 powder while α-Al 2 O 3 , BC as reported previously by 24 . A slight peak shift was also observed, which can be related to quenching stresses produced when the particles reached the substrate and rapidly solidified.…”

Section: Bond Coat Characterizationsupporting

confidence: 83%

“…A slight peak shift was also observed, which can be related to quenching stresses produced when the particles reached the substrate and rapidly solidified. In flame spraying process, unlike HVOF process, aluminum gets oxidized extensively forming Al 2 O 3 during deposition, contributing also to the peaks shift as reported by Rana et al 24 .…”

Section: Bond Coat Characterizationmentioning

confidence: 77%

“…Likewise, the cross-section of the BC layer Figure 2b exhibited oxidized areas around lamellae which were produced during the spraying process due to the slightly oxidizing combustion flame used for the deposition of this layer. The oxidation of some elements present in the thermally sprayed metallic powder NiCrAlY are reported by Rana et al 24,25 where alumina is the oxide predominantly produced, which increases the oxidation resistance of the coating. The arithmetic average roughness Ra of the bond coat was 9.4 ± 1.8 µm.…”

Section: Bond Coat Characterizationmentioning

confidence: 92%

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Effect of Flame Spray Deposition Parameters on The Microstructure of Al2 O3 - 13 %TiO2 Coatings Applied Onto 7075 Aluminum Alloy

et al. 2018

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In this work, the effect of flame spraying parameters on physical, structural and microstructural characteristics of Al 2 O 3-13 wt.% TiO 2 (AT-13) coatings were studied. NiCrAl and AT-13 feedstock powders were used for spraying a bond coat (BC) and a top coat (TC), respectively, onto a 7075 aluminum alloy substrate. The effect of acetylene-to-oxygen ratio and the spraying distance on surface roughness, crystalline phases, porosity and thickness of top coat were analyzed. The results showed that for the evaluated spraying conditions, the volumetric oxy-fuel ratio had significant effects on roughness, porosity and crystalline phases of the coating. On the other hand, the spraying distance affected the thickness of the coating and did not influence the formation of Al 2 TiO 5 phase; no significant effect of spraying distance on roughness was observed. The results showed that an acetylene: oxygen volumetric ratio of 1:2.5 is preferable to obtain higher melting of the ceramic powders and therefore a denser coating with major content of γ-Al 2 O 3 crystalline phase.

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Section: Bond Coat Characterizationsupporting

confidence: 83%

Section: Bond Coat Characterizationmentioning

confidence: 77%

Section: Bond Coat Characterizationmentioning

confidence: 92%

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Effect of Flame Spray Deposition Parameters on The Microstructure of Al2 O3 - 13 %TiO2 Coatings Applied Onto 7075 Aluminum Alloy

et al. 2018

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“…Various attempts on surface treatment of TiAl alloy have been applied to improve the property of oxidation resistance [7][8][9][10]. M Taheri et al [11] have been succeeded in forming NiCrAlY or CoNiCrAlYSi coating on the surface of TiAl alloy to improve the oxidation resistance.…”

Section: Introductionmentioning

confidence: 99%

Oxidation Behavior of Al-Y Coating on γ-TiAl at 900°C

et al. 2019

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In this study, an Al-Y coating was applied to enhance the property of oxidation resistance on the surface of γ-TiAl alloys by rf magnetron sputtering. The isothermal oxidation tests were investigated at 900 °C for 100 h. The coating characteristics and microstructure of coating after isothermal oxidation were inspected by XRD and SEM methods respectively, and coating bonding strength was investigated by scratch tester. Results show that Al 2 O 3 and Y 2 O 3 were produced on the surface of γ-TiAl alloys to enhance oxidation resistance during the isothermal oxidation test. Diffusion layer with rich element of Al provides abundant Al to surface for formation of a continuous Al 2 O 3 layer which increases oxidation resistance effectively. Oxides of YAlO 3 and YAG were formed during the oxidation tests, which were beneficial for the strength, hardness and fracture toughness of crystal grain of Al 2 O 3. Furthermore, Element of Ti diffused into surface from substrate was restrained by Al because of the formation of TiAl 3 and TiAl, which avoid the layer-broken by titanium oxides with porous structure

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“…Cr is a commonly used alloying element in materials for high-temperature applications (\ 850°C) that can form a stable oxide (Cr 2 O 3 ) with hexagonal corundum structure. Cr is also a typical alloying element in many thermal spray powder chemistries such as Ni21Cr, Ni49Cr, and MCrAlY (M = Ni, Co, or/and Fe) to provide high-temperature corrosion protection ( Ref 75,78,167). The diffusion of a corrosive species through Cr 2 O 3 is rather slow.…”

Section: Crmentioning

confidence: 99%

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants. Part I: Effect of Composition and Microstructure

2019

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Power generation from renewable resources has attracted increasing attention in recent years owing to the global implementation of clean energy policies. However, such power plants suffer from severe high-temperature corrosion of critical components such as water walls and superheater tubes. The corrosion is mainly triggered by aggressive gases like HCl, H 2 O, etc., often in combination with alkali and metal chlorides that are produced during fuel combustion. Employment of a dense defect-free adherent coating through thermal spray techniques is a promising approach to improving the performances of components as well as their lifetimes and, thus, significantly increasing the thermal/electrical efficiency of power plants. Notwithstanding the already widespread deployment of thermal spray coatings, a few intrinsic limitations, including the presence of pores and relatively weak intersplat bonding that lead to increased corrosion susceptibility, have restricted the benefits that can be derived from these coatings. Nonetheless, the field of thermal spraying has been continuously evolving, and concomitant advances have led to progressive improvements in coating quality; hence, a periodic critical assessment of our understanding of the efficacy of coatings in mitigating corrosion damage can be highly educative. The present paper seeks to comprehensively document the current state of the art, elaborating on the recent progress in thermal spray coatings for high-temperature corrosion applications, including the alloying effects, and the role of microstructural characteristics for understanding the behavior of corrosion-resistant coatings. In particular, this review comprises a substantive discussion on high-temperature corrosion mechanisms, novel coating compositions, and a succinct comparison of the corrosion-resistant coatings produced by diverse thermal spray techniques.

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High-Temperature Oxidation and Hot Corrosion Studies on NiCrAlY Coatings Deposited by Flame-Spray Technique

Cited by 30 publications

References 32 publications

Effect of Flame Spray Deposition Parameters on The Microstructure of Al2 O3 - 13 %TiO2 Coatings Applied Onto 7075 Aluminum Alloy

Effect of Flame Spray Deposition Parameters on The Microstructure of Al2 O3 - 13 %TiO2 Coatings Applied Onto 7075 Aluminum Alloy

Oxidation Behavior of Al-Y Coating on γ-TiAl at 900°C

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants. Part I: Effect of Composition and Microstructure

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