Effect of hot corrosion on the mechanical performances of superalloys and coating systems

Yoshiba, Masayuki

doi:10.1016/0010-938x(93)90331-a

Cited by 40 publications

(18 citation statements)

References 6 publications

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“…[1] The Ni-based superalloys are well known to be susceptible to hot corrosion associated with combined reaction processes such as sulfidation-oxidation and occasionally together with chlorination. In practice, it is a serious problem for such alloy systems when used for hot section components of various heat engines such as gas turbines [2] and steam generating plants. In such environments, protective coatings on the surface of superalloys are frequently considered.…”

Section: Introductionmentioning

confidence: 99%

Corrosion behavior of plasma-sprayed coatings on a Ni-base superalloy in Na2SO4-60 Pct V2O5 environment at 900 °C

Singh

Puri

Prakash

2005

Metall Mater Trans A

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The shrouded plasma spray process was used to deposit NiCrAlY, Ni-20Cr, Ni 3 Al, and Stellite-6 metallic coatings on a Ni-based superalloy (62Ni-23Cr-1.48Al-0.80Mn-0.37Si-0.10Cu-0.025C-bal Fe). NiCrAlY was used as a bond coat in all 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 the kinetics of corrosion. X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDAX) and electron-probe microanalysis techniques were used to analyze the corrosion products. The uncoated superalloy suffered accelerated corrosion in the form of intense spalling of the scale. The 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 developing resistance against hot corrosion, which may be attributed to the formation of oxides, and spinels of nickel, aluminum, chromium, or cobalt.

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Section: Introductionmentioning

confidence: 99%

Corrosion behavior of plasma-sprayed coatings on a Ni-base superalloy in Na2SO4-60 Pct V2O5 environment at 900 °C

Singh

Puri

Prakash

2005

Metall Mater Trans A

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“…Alpha-alumina acts as a diffusion barrier, minimising diffusion of substrate elements to the surface (Rhys-Jones,1989;Müller & Neuschütz, 2003), due to its high thermal stability at high temperatures (Zheng et al, 2006) and low solubility in molten salts (Chen et al, 2003). A crucible test was then conducted at 950°C to increase the corrosion kinetics (Potgieter et al, 2010), as hot corrosion is more damaging at this temperature (Elliot, 1990;Yoshiba, 1993). Five Pt-based alloys and two single-crystal CMSX-4 superalloy samples were tested.…”

Section: Corrosion Testsmentioning

confidence: 99%

Platinum-Based Alloys and Coatings: Materials for the Future?

Cornish¹,

Chown²

2011

Advances in Gas Turbine Technology

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“…Plasma techniques are capable of producing thick coatings films more than 100 lm at high production rates with no degradation of the mechanical properties of the alloy substrate [15]. But problems that may be encountered are porosity and poor adhesion, especially in case of adhesion of ceramics to metals.…”

Section: Plasma Sprayingmentioning

confidence: 99%

“…The demand for the protective coatings has increased recently for almost all types of superalloys with improved strength, since high-temperature corrosion problem become much more significant for these alloys with increasing operating temperatures of modern heat engines [15]. The desire for higher operating temperature, improved performance, extended component lives, and cleaner and more fuel-efficient power plant/processes places severe demands on the structural materials used to construct such a high-temperature plant.…”

Section: Introductionmentioning

confidence: 99%

Use of plasma spray technology for deposition of high temperature oxidation/corrosion resistant coatings – a review

Singh¹,

Sidhu

Puri

et al. 2007

Materials & Corrosion

109

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High temperature oxidation is one of the main failure modes of the hot-section components in gas turbines, boilers, waste incinerations, diesel engines, coal gasification plants, chemical plants and other energy generation systems. In such applications the use of Fe-, Ni-and Co-based alloys, especially of superalloys is well known. The superior mechanical strength and good corrosion resistance of the superalloys at high temperature make them favorites for such applications. However, the presence of combustion gases constitutes an extreme environment and hot corrosion is inevitable when superalloys are used at high temperatures for long durations of time. Therefore these alloys need to be protected against this type of oxidation. Several countermeasures have been suggested in the literature to combat the same. One such countermeasure against hot corrosion and oxidation constitutes the deposition of protective coatings on these alloys. Among the various techniques used for deposition of coatings, plasma spraying is a versatile technology that has been successful as a reliable cost-effective solution for many industrial problems. It allows the spraying of a wide range of high performance materials from superalloys and refractory intermetallic compounds to ceramics with continuously increasing commercial applications. Furthermore it does not cause deterioration of the substrate alloys, and relatively thick coatings can be formed with high deposition rates. In this paper the technique of plasma spraying has been detailed and the role of plasma sprayed coatings to arrest high temperature oxidation has been discussed with the help of a comprehensive literature survey. The main focus of this investigation is the studies related to plasma sprayed NiCrAlY, Ni-Cr, Nickel aluminide and Co-based coatings.

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Effect of hot corrosion on the mechanical performances of superalloys and coating systems

Cited by 40 publications

References 6 publications

Corrosion behavior of plasma-sprayed coatings on a Ni-base superalloy in Na2SO4-60 Pct V2O5 environment at 900 °C

Corrosion behavior of plasma-sprayed coatings on a Ni-base superalloy in Na2SO4-60 Pct V2O5 environment at 900 °C

Platinum-Based Alloys and Coatings: Materials for the Future?

Use of plasma spray technology for deposition of high temperature oxidation/corrosion resistant coatings – a review

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