Mechanism of formation of corrosion layers on nickel and nickel-based alloys in melts containing oxyanions—a review

Tzvetkoff, Tzvety; Gencheva, Petia

doi:10.1016/j.matchemphys.2003.08.001

Cited by 35 publications

(20 citation statements)

References 41 publications

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“…This is because these elements are the main components of both austenitic stainless steels as the Ni-based superalloys. On the other hand, chromium is the main alloying element to ensure the corrosion resistance of these materials [15].…”

Section: Introductionmentioning

confidence: 99%

EIS Evaluation of Fe, Cr, and Ni in NaVO₃at 700°C

Sotelo-Mazón

Porcayo-Calderón

Cuevas-Arteaga

et al. 2014

Journal of Spectroscopy

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Due to the depletion of high-grade fuels and for economic reasons, use of residual fuel oil in energy generation systems is a common practice. Residual fuel oil contains sodium, vanadium, and sulphur as impurities, as well as NaCl contamination. Metallic dissolution caused by molten vanadates has been classically considered the main corrosion process involved in the degradation of alloys exposed to the combustion products of heavy fuel oils. Iron and nickel base alloys are the commercial alloys commonly used for the high temperature applications, for example, manufacture of components used in aggressive environments of gas turbines, steam boilers, and so forth. Therefore, because the main constituents of these materials are Fe, Cr, and Ni, where Cr is the element responsible for providing the corrosion resistance, in this study the electrochemical performance of Fe, Cr, and Ni in NaVO3at 700°C in static air for 100 hours was evaluated.

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Section: Introductionmentioning

confidence: 99%

EIS Evaluation of Fe, Cr, and Ni in NaVO₃at 700°C

Sotelo-Mazón

Porcayo-Calderón

Cuevas-Arteaga

et al. 2014

Journal of Spectroscopy

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“…Various studies have been done on corrosion of structural materials in molten salts, focusing on corrosion under various gas atmospheres and mechanisms involved. [2][3][4][5] It has been widely accepted that Ni-rich alloys suffer from less attack in chlorine-containing environments than carbon steels and stainless steel. 2 Hosoya, et al, 6 conducted a study on the compatibility of structural materials with molten chloride mixture at high temperature and showed that Ni-based super alloy, i.e., UNS N06002, (1) is exceedingly resistive against oxidation owing to its adherent oxide scale.…”

Section: Introductionmentioning

confidence: 99%

Corrosion of Nickel-Containing Alloys in Molten LiCl-KCl Medium

Shankar¹,

Kanagasundar²,

Mudali³

2013

CORROSION

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Pyrochemical reprocessing utilizing molten chloride salt has been considered one of the best options for reprocessing of spent metallic fuels of future fast breeder reactors. Materials for pyrochemical reprocessing applications should possess high-temperature strength, corrosion, and scale resistance. The present work discusses the corrosion behavior of Ni-based alloys 600 (UNS N06600), 625 (UNS N06625), and 690 (UNS N06690) and alloy 800H (UNS N08810) exposed to molten lithium chloride-potassium chloride (LiCl-KCl) eutectic salt at 673, 773, and 873 K for 2 h in the presence of air. The corrosion rates of the samples were determined and surface morphology of the exposed samples and scales were examined using scanning electron microscopy (SEM), x-ray diffraction (XRD), and laser Raman spectroscopy (LRS) . The results indicated that Ni-based alloys (UNS N06600 and UNS N06690) offer better corrosion resistance compared to Ni-based alloy (UNS N06625) and alloy 800H (UNS N08810) because the presence of Mo in Ni-based alloy (UNS N06625) is not beneficial for molten salt environment in air. Based on the surface morphology, XRD, and cross-sectional energy-dispersive x-ray (EDX) analyses of scales and exposed samples, the mechanism of corrosion of alloys appears to be from the formation of Cr-rich and Ni-rich layers of chromium(III) oxide (Cr 2 O 3 ), nickel oxide (NiO),and spinel oxides at the surface and subsequent spallation. The paper highlights the results of the present investigation. KEy wORDS: high-temperature corrosion, scanning electron microscopy, super alloys, x-ray diffraction ISSN 0010-9312 (print), 1938-159X (online) 13/000011/$5.00+$0.50/0 © 2013, NACE International CORROSION SCIENCE SECTION CORROSION-Vol. 69, No. 1 49 FIGURE 9. LRS of scales formed at 873 K/2 h on Ni-based alloys.

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“…Various studies have been reported on the corrosion of structural materials in molten chlorides, focusing on the corrosion under inert atmosphere or in the presence of oxygen and mechanisms involved. [3][4][5][6] In the present study, electroformed nickel (EF Ni), electroformed nickel with nickel-tungsten (Ni-W) coating (EF Ni-W), 316L SS, and INCONEL* 625 were chosen as the candidate materials for testing.…”

Section: Introductionmentioning

confidence: 99%

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium

Shankar

Mathiya²,

Thyagarajan

et al. 2010

Metall Mater Trans A

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Pyrochemical reprocessing in molten chloride salt medium has been considered as one of the best options for the reprocessing of spent metallic fuels of future fast breeder reactors. The unit operations such as salt preparation, electrorefining, and cathode processing involve the presence of molten LiCl-KCl eutectic salt from 673 to 1373 K (400 to 1100°C). The present work discusses the corrosion behavior of electroformed nickel (EF Ni) without and with nickel-tungsten (Ni-W) coating, 316L SS, and INCONEL 625 alloy in molten LiCl-KCl eutectic salt at 673 K, 773 K, and 873 K (400°C, 500°C, and 600°C) in the presence of air. The weight percent loss of the exposed samples was determined by the weight loss method and surface morphology of the salt exposed, and product layers were examined by scanning electron microscopy (SEM). X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were also carried out on the exposed and corrosion product layers to understand the phases present and the corrosion mechanism involved. The results of the present study indicated that INCONEL 625 alloy showed superior corrosion resistance compared to electroformed nickel (EF Ni), EF Ni with nickel-tungsten (Ni-W) coating (EF Ni-W), and 316L SS. The EF Ni with Ni-W coating exhibits better corrosion resistance than EF Ni without tungsten coating. Based on the surface morphology, XRD, and EDX analysis of corrosion product layers, the mechanism of corrosion of INCONEL 625 and 316L involves formation of chromium-rich compound at the surface and subsequent spallation. For the EF Ni, the porous thick NiO corrosion product allows the penetration of salt, thus accelerating the corrosion. Improved corrosion resistance of EF Ni-W was attributed to the W-rich NiO layer, while for INCONEL 625, the adherent and protective NiO layer improved the corrosion resistance. The article highlights the results of the present investigation.

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Mechanism of formation of corrosion layers on nickel and nickel-based alloys in melts containing oxyanions—a review

Cited by 35 publications

References 41 publications

EIS Evaluation of Fe, Cr, and Ni in NaVO₃at 700°C

EIS Evaluation of Fe, Cr, and Ni in NaVO₃at 700°C

Corrosion of Nickel-Containing Alloys in Molten LiCl-KCl Medium

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium

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Mechanism of formation of corrosion layers on nickel and nickel-based alloys in melts containing oxyanions—a review

Cited by 35 publications

References 41 publications

EIS Evaluation of Fe, Cr, and Ni in NaVO3at 700°C

EIS Evaluation of Fe, Cr, and Ni in NaVO3at 700°C

Corrosion of Nickel-Containing Alloys in Molten LiCl-KCl Medium

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium

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Product

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EIS Evaluation of Fe, Cr, and Ni in NaVO₃at 700°C

EIS Evaluation of Fe, Cr, and Ni in NaVO₃at 700°C