Evaluation of the corrosion behaviour of plasma-sprayed Ni3Al coatings on steel in oxidation and molten salt environments at 900 °C

Sidhu, Buta Singh; Prakash, S.

doi:10.1016/s0257-8972(02)00772-7

Cited by 141 publications

(45 citation statements)

References 18 publications

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“…39) In the current study, the same has been observed as nickel oxide is revealed from the XRD analysis alongwith small amounts of Al 2 O 3 . Sidhu and Prakash 17) and Malik et al 40) also reported the similar phases in their studies on Ni 3 Al coatings on boiler steels. The presence of NiO and NiAl 2 O 4 phases was also observed by Lee and Lin 41) during hot corrosion studies on Ni 3 Al intermetallic compound at 800 and 1 000°C.…”

Section: Discussionsupporting

confidence: 56%

Hot Corrosion Behaviour of Plasma Sprayed Coatings on a Ni-based Superalloy in Na2SO4-60%V2O5 Environment

2005

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NiCrAlY, Ni 3 Al and Stellite-6 metallic coatings were deposited on a Ni-based . NiCrAlY was used as bond coat in all the cases. Hot corrosion studies were conducted on uncoated as well as plasma spray coated superalloy specimens after exposure to molten salt at 900°C under cyclic conditions. The thermogravimetric technique was used to establish kinetics of corrosion. X-Ray Diffraction, SEM/EDAX and EPMA techniques were used to analyse the corrosion products. The uncoated superalloy suffered a catastrophic corrosion in the form of intense spalling of the scale accompanied by disintegration of the scale with cracking sounds. NiCrAlY coated specimen showed a minimum weight gain, whereas the Stellite-6 indicated a maximum weight gain among the coatings studied. All the coatings were found to be successful in reducing spalling of the superalloy substrate. It is concluded that the formation of oxides and spinels containing nickel, aluminium, chromium or cobalt contributes to an improved hot corrosion resistance.KEY WORDS: hot corrosion; plasma spray coatings; superalloy; NiCrAlY; and protective coatings.ronments consisting of different compositions of Na 2 SO 4 , K 2 SO 4 , NaCl, KCl salts in oxidising as well as reducing atmospheres of mixed gases. Singh and Prakash 17) studied the corrosion behaviour of plasma-sprayed Ni 3 Al coatings on boiler steels in oxidation and molten salt environments at 900°C and found these coating quite effective in developing hot corrosion resistance.The MCrAlY bond coats provide a rough surface for mechanical bonding of the ceramic top coat, protect the underlying alloy substrate against high temperature oxidation corrosion and minimize the effect of thermal expansion mismatch between the substrate and the ceramic top coat materials. 18)Although considerable insight has been accumulated on oxidation behaviour of NiCrAlY and Ni-20Cr coatings and to some extent of Ni 3 Al coatings on Ni-base superalloys in air as well as in aggressive environments at high temperatures, but no information is available on the high temperature oxidation behaviour of these coatings in an aggressive environment of molten salt (Na 2 SO 4 -60 %V 2 O 5 ), which has much lower melting point (Ϸ500°C) than other compositions of Na 2 SO 4 -V 2 O 5 mixtures as per the open literature. 19)Similarly the investigation will provide vital information on the hot corrosion behaviour of plasma spray Stellite-6 coatings, which will be useful for studying its use in combined corrosion and wear situations. Uusitalo et al. 15) have also realized that there is a little discussion of high temperature corrosion testing on thermal sprayed coatings in literature. Moreover, due to the intrinsic properties of thermal spraying technique, it must be emphasized that more work is needed in order to get a reliable corrosion resistant coating in many environments. 20)The objective of the work is to characterise the high temperature corrosion mechanisms for plasma spray metallic coatings of NiCrAlY, Ni-20Cr, Ni 3 Al and Stellite-6 on a ...

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Section: Discussionsupporting

confidence: 56%

Hot Corrosion Behaviour of Plasma Sprayed Coatings on a Ni-based Superalloy in Na2SO4-60%V2O5 Environment

2005

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“…Further, the nickel-aluminide coatings can also protect other metal substrates with different preparation methods. For example, the SHS (self-propagating high-temperature synthesis) casting route can prepare a Ni 3 Al coating to protect carbon steel [5], a plasma-sprayed Ni 3 Al coating can protect boiler tube steels [6,7], a mechanical alloying to format nanostructure NiAl can defend carbon steel [8], and a two-step process to make nickel aluminide/nickel hybrid coatings can shield alloy steel [9] or TiAl alloy [10]. Compared to the other methods mentioned above, the two-step process can aluminize at low temperature by pack aluminization of preliminarily nickel-coated samples [9].…”

Section: Introductionmentioning

confidence: 99%

Composition Distribution and Electrochemical Behavior of an Ni2Al3 Coating on Q235 Steel

Wang

Zheng

et al. 2016

Metals

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An Ni 2 Al 3 coating was prepared via the electrodeposition of nickel followed by pack aluminization. Polarization curve and electrochemical impedance spectroscopy were performed to study the room temperature corrosion behavior of the coating in a 3.5 wt. % NaCl solution. The long-term impedance of the coating was also investigated after immersion for 30 days. Results show that the Ni 2 Al 3 coating possessed lower corrosion current density (I corr ) and higher polarization resistance (R p ) than the substrate in the solution. The Bode plots of the coating showed two time constants after the long-term immersion. Pitting corrosion was found on the coating surface.

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“…(4) Donde R y dl corresponden a los coeficientes de dispersión en el primer y segundo ciclo de la capacitancia; en consecuencia, CRCot(R/2) y CdlCot(dl/2) son elementos de impedancia causados por el efecto de dispersión.…”

Section: Resultados Y Análisisunclassified

“…El daño causado por esta interacción puede traducirse en pérdida de substrato por oxidación o corrosión a alta temperatura o por la pérdida de la resistencia mecánica del sustrato debido a la difusión de especies perjudiciales a la aleación base a altas temperaturas [4].…”

Section: Introductionunclassified

Resistencia a la corrosión a alta temperatura de recubrimientos NiCrAlY y NiCrFeNbMoTiAl depositados por APS

2014

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ResumenLa corrosión a alta temperatura de las tuberías utilizadas en equipos generadores de vapor (calderas) ha sido reconocida como un grave problema que trae consigo el adelgazamiento de éstas y, por consiguiente, la falla de los equipos. En la última década se han incrementado las investigaciones que involucran recubrimientos protectores que ayudan de alguna manera a prolongar la vida útil de estos equipos. Esta investigación determinó el comportamiento de los recubrimientos NiCrAlY y NiCrFeNbMoTiAl depositados por proyección térmica asistida por plasma (APS) sobre la aleación SA213 -T22 (2¼Cr -1Mo), en un ambiente corrosivo de 80%V 2 O 5 -20%K 2 SO 4 a 800°C. Los valores de la cinética de corrosión fueron determinados mediante resistencia a la polarización lineal (RPL) y espectroscopia de impedancia electroquímica (EIE). Los resultados obtenidos muestran una menor cinética de corrosión en el recubrimiento NiCrFeNbMoTiAl que la presentada por el recubrimiento NiCrAlY, corroborado por Microscopia Electrónica de Barrido (MEB).Palabras clave: Corrosión a alta temperatura, Electroquímica, Recubrimientos, APS.

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Evaluation of the corrosion behaviour of plasma-sprayed Ni3Al coatings on steel in oxidation and molten salt environments at 900 °C

Cited by 141 publications

References 18 publications

Hot Corrosion Behaviour of Plasma Sprayed Coatings on a Ni-based Superalloy in Na2SO4-60%V2O5 Environment

Hot Corrosion Behaviour of Plasma Sprayed Coatings on a Ni-based Superalloy in Na2SO4-60%V2O5 Environment

Composition Distribution and Electrochemical Behavior of an Ni2Al3 Coating on Q235 Steel

Resistencia a la corrosión a alta temperatura de recubrimientos NiCrAlY y NiCrFeNbMoTiAl depositados por APS

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