A study on hot corrosion behaviour of Ni–5Al coatings on Ni- and Fe-based superalloys in an aggressive environment at 900°C

Mahesh, R.; Jayaganthan, R.; Prakash, S.

doi:10.1016/j.jallcom.2007.05.092

Cited by 47 publications

(14 citation statements)

References 24 publications

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“…Today, numerous Ni‐ and Fe‐based superalloys are used as structural components in various applications, such as gas turbines, steam boilers, heat exchangers, aero engines, and industrial springs, as they possess superior mechanical properties along with corrosion and oxidation resistance to some extent. These superalloys cannot provide high‐temperature corrosion resistance without affecting mechanical properties, as tailoring of microstructural and compositional parameters to achieve the former would have an adverse effect on the later . Tiwari and Prakash evaluated hot corrosion behavior of superalloys in pure Na 2 SO 4 , Na 2 SO 4 –15%V 2 O 5 and Na 2 SO 4 –60%V 2 O 5 in the temperature range of 700–900°C.…”

Section: Introductionmentioning

confidence: 99%

High‐temperature corrosion behavior of some post‐plasma‐spraying‐gas‐nitrided metallic coatings on a Fe‐based superalloy

Chawla

Sidhu

Rani

et al. 2019

Materials & Corrosion

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The objective of the present study is to propose a cost-effective process for modifying commercially available coatings by gas nitriding using commonly available equipment and starting materials. Al-Cr and Ti-Al metallic coatings were deposited on Superfer 800H (Fe-based superalloy) using a plasma spray process. Then the gas nitriding of the coatings was done in the lab and the parameters were optimized after conducting several trials on plasma-sprayedcoated specimens. Characterization and high-temperature corrosion behavior of coatings after exposure to air and molten salt at 900°C were studied under cyclic conditions. Techniques like XRD, SEM/EDX, and X-ray mapping analysis were used for the characterization of the coatings and analysis of the oxide scale. Both the coatings successfully protected the substrate and were effective in decreasing the corrosion rate when subjected to cyclic oxidation (Type-I hot corrosion) at 900°C for 50 cycles in air and molten salt (a salt mixture of Na 2 SO 4 -60%V 2 O 5 dissolved in distilled water). Based on the findings of the present study, the coatings under study are recommended for tapplications to super-heater and reheater tubes of boilers and all those surfaces that face fireside corrosion, such as fluidized beds, industrial waste incinerators, internal combustion engines, gas turbines or steam turbines, to provide protection against degradation in these environments. The cost of the product/process is approximately Rs. 0.62 per mm 2 in case of Al-Cr coating and Rs. 1.86 per mm 2 in case of Ti-Al coating.

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Section: Introductionmentioning

confidence: 99%

High‐temperature corrosion behavior of some post‐plasma‐spraying‐gas‐nitrided metallic coatings on a Fe‐based superalloy

Chawla

Sidhu

Rani

et al. 2019

Materials & Corrosion

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“…The presence of additions such as Al and Ti would provide better corrosion resistance of the weld region of ERNiCu-7 weldments. Jayaganthan et al 18 conducted hot corrosion studies on Ni and Fe-based superalloys in an aggressive environment containing Na 2 SD 4 -60%V 2 D 5 at 900 °C. They reported that NaVD 3 acts as a catalyst and also serves as an oxygen carrier to the base alloy through the open pores present on the surface, which will lead to the rapid corrosion.…”

Section: Discussionmentioning

confidence: 99%

Hot corrosion behavior of monel 400 and AISI 304 dissimilar weldments exposed in the molten salt environment containing Na2SO4 + 60% V2O5 at 600 °C

2014

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This research work investigates the use of pulsed current for joining two dissimilar metals Monel 400 and AOSO 304 using Pulsed Current Gas Tungsten Arc welding using three different filler metals such as ER309L, ERNiCu-7 and ERNiCrFe-3. Microstructure observations showed the presence of Partially Melted Zone (PMZ) at the heat affected zone (HAZ) of all the weldments. The formation of secondary phases was witnessed at the HAZ of Monel 400 on using ERNiCu-7 filler. Tensile studies corroborated that the bimetallic combinations employing ERNiCu-7 offer better tensile properties as compared to ER309L and ERNiCrFe-3 weldments. Parent metal Monel 400 exhibited better corrosion resistance as compared to other zones of the weldments when exposed in the synthetic molten salt environment containing Na 2 SD 4 -60% V 2 D 5 environment at 600 °C. A detailed structure -property relationship was made using the combined techniques of optical microscopy and SEM. Also the hot corrosion products were revealed using the thermogravimetric plots, XRD and SEM/EDAX analysis.

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“…This increased hardness value near the coating/substrate interface might be due to the work hardening effect of the sandblasting of the substrates before the coating process as reported by the authors' institute research group. [46][47][48][49][50] The hardening of substrate superalloys may also be partly attributed to the high speed impact of the coating particles during Dgun spraying. Similar phenomena have also been observed in the authors' previous publications.…”

Section: Discussionmentioning

confidence: 99%

Mechanical and microstructural characterisations of NiCrCoAlYTa coatings on superalloys deposited by detonation gun technique

Kamal

Jayaganthan

Prakash

2009

Surface Engineering

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The microstructure and mechanical properties of detonation gun sprayed NiCoCrAlYTa alloy coatings on the selected superalloys were investigated. The coatings were characterised in relation to thickness, porosity, microhardness, microstructure, compositions, and phases across by using the techniques such as optical microscopy, X-ray diffraction, field emission scanning electron microscopy/energy dispersive analysis and X-ray mapping. The formation of spherical or elliptical shaped dendritic splats was observed in the as sprayed coatings on the superalloys. The splat morphology of the coatings is due to the deposition and re-solidification of successive molten or semimolten powder particles. The coatings showed a bond strength of 50 MPa and the surface roughness (arithmetic average height) of the coatings was found to be in the range of 6?25-7?48 mm. The porosity and microhardness of the coatings were less than 0?48% and 385-748 Hv respectively. The XRD analysis of the coatings showed the phases c-Ni or c9-Ni 3 Al and b-NiAl inter metallic as the minor phase. 7 Cross-section morphology of NiCoCrAlYTa coated superalloys in as sprayed condition and cross-section EDS line scan of a superni 75, b superni 718 and c superfer 800HKamal et al. Mechanical and microstructural characterisations of NiCrCoAlYTa coatings on superalloys Surface Engineering 2009 VOL 25 NO 4 Surface Engineering 2009 VOL 25 NO 4 6 Continued Kamal et al. Mechanical and microstructural characterisations of NiCrCoAlYTa coatings on superalloys Surface Engineering 2009 VOL 25 NO 4

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A study on hot corrosion behaviour of Ni–5Al coatings on Ni- and Fe-based superalloys in an aggressive environment at 900°C

Cited by 47 publications

References 24 publications

High‐temperature corrosion behavior of some post‐plasma‐spraying‐gas‐nitrided metallic coatings on a Fe‐based superalloy

High‐temperature corrosion behavior of some post‐plasma‐spraying‐gas‐nitrided metallic coatings on a Fe‐based superalloy

Hot corrosion behavior of monel 400 and AISI 304 dissimilar weldments exposed in the molten salt environment containing Na2SO4 + 60% V2O5 at 600 °C

Mechanical and microstructural characterisations of NiCrCoAlYTa coatings on superalloys deposited by detonation gun technique

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