KCl-induced corrosion of Ni-based alloys containing 35–45 wt% Cr

Yohanes C. Malede*, Julien P. Simon, Torbjörn Jonsson, Melanie Montgomery, Kristian V. Dahl, John Hald

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Ni–(35–45)Cr–4Nb alloys containing different fractions of α‐Cr were exposed to potassium chloride (KCl)‐induced corrosion. The corrosion exposures were carried out for 168 hr at 600°C in a 15% (vol/vol) H2O (g) + 5% (vol/vol) O2 (g) + N2 (g; balance) atmosphere using KCl‐free (reference) and predeposited KCl samples. To mimic the KCl deposition in real boilers, 24 hr exposures where KCl vapor condensed continuously onto samples were also performed. The corrosion attack of the studied materials increased significantly when KCl was present compared to the KCl‐free samples. For the KCl exposures, the corrosion attack drastically increased when a significant α‐Cr fraction was present. α‐Cr was either selectively attacked or dissolved through solid‐state diffusion and a layered build‐up of the outer external scale of K2CrO4 and chromia could be observed. For the in situ condensed KCl exposure, severe corrosion was observed already within the 24 hr exposure, indicating a higher corrosion rate compared with when KCl was predeposited.
Original languageEnglish
JournalMaterials and Corrosion
Volume70
Issue number8
Pages (from-to)1486-1506
ISSN0947-5117
DOIs
Publication statusPublished - 2019

Keywords

  • KCl-induced high-temperature corrosion
  • Ni–Cr–Nb alloys
  • Phase dissolution
  • Selective attack
  • α-Cr

Cite this

Malede, Yohanes C. ; Simon, Julien P. ; Jonsson, Torbjörn ; Montgomery, Melanie ; Dahl, Kristian V. ; Hald, John. / KCl-induced corrosion of Ni-based alloys containing 35–45 wt% Cr. In: Materials and Corrosion. 2019 ; Vol. 70, No. 8. pp. 1486-1506.
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title = "KCl-induced corrosion of Ni-based alloys containing 35–45 wt{\%} Cr",
abstract = "Ni–(35–45)Cr–4Nb alloys containing different fractions of α‐Cr were exposed to potassium chloride (KCl)‐induced corrosion. The corrosion exposures were carried out for 168 hr at 600°C in a 15{\%} (vol/vol) H2O (g) + 5{\%} (vol/vol) O2 (g) + N2 (g; balance) atmosphere using KCl‐free (reference) and predeposited KCl samples. To mimic the KCl deposition in real boilers, 24 hr exposures where KCl vapor condensed continuously onto samples were also performed. The corrosion attack of the studied materials increased significantly when KCl was present compared to the KCl‐free samples. For the KCl exposures, the corrosion attack drastically increased when a significant α‐Cr fraction was present. α‐Cr was either selectively attacked or dissolved through solid‐state diffusion and a layered build‐up of the outer external scale of K2CrO4 and chromia could be observed. For the in situ condensed KCl exposure, severe corrosion was observed already within the 24 hr exposure, indicating a higher corrosion rate compared with when KCl was predeposited.",
keywords = "KCl-induced high-temperature corrosion, Ni–Cr–Nb alloys, Phase dissolution, Selective attack, α-Cr",
author = "Malede, {Yohanes C.} and Simon, {Julien P.} and Torbj{\"o}rn Jonsson and Melanie Montgomery and Dahl, {Kristian V.} and John Hald",
year = "2019",
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language = "English",
volume = "70",
pages = "1486--1506",
journal = "Materials and Corrosion",
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KCl-induced corrosion of Ni-based alloys containing 35–45 wt% Cr. / Malede, Yohanes C.; Simon, Julien P.; Jonsson, Torbjörn; Montgomery, Melanie; Dahl, Kristian V.; Hald, John.

In: Materials and Corrosion, Vol. 70, No. 8, 2019, p. 1486-1506.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - KCl-induced corrosion of Ni-based alloys containing 35–45 wt% Cr

AU - Malede, Yohanes C.

AU - Simon, Julien P.

AU - Jonsson, Torbjörn

AU - Montgomery, Melanie

AU - Dahl, Kristian V.

AU - Hald, John

PY - 2019

Y1 - 2019

N2 - Ni–(35–45)Cr–4Nb alloys containing different fractions of α‐Cr were exposed to potassium chloride (KCl)‐induced corrosion. The corrosion exposures were carried out for 168 hr at 600°C in a 15% (vol/vol) H2O (g) + 5% (vol/vol) O2 (g) + N2 (g; balance) atmosphere using KCl‐free (reference) and predeposited KCl samples. To mimic the KCl deposition in real boilers, 24 hr exposures where KCl vapor condensed continuously onto samples were also performed. The corrosion attack of the studied materials increased significantly when KCl was present compared to the KCl‐free samples. For the KCl exposures, the corrosion attack drastically increased when a significant α‐Cr fraction was present. α‐Cr was either selectively attacked or dissolved through solid‐state diffusion and a layered build‐up of the outer external scale of K2CrO4 and chromia could be observed. For the in situ condensed KCl exposure, severe corrosion was observed already within the 24 hr exposure, indicating a higher corrosion rate compared with when KCl was predeposited.

AB - Ni–(35–45)Cr–4Nb alloys containing different fractions of α‐Cr were exposed to potassium chloride (KCl)‐induced corrosion. The corrosion exposures were carried out for 168 hr at 600°C in a 15% (vol/vol) H2O (g) + 5% (vol/vol) O2 (g) + N2 (g; balance) atmosphere using KCl‐free (reference) and predeposited KCl samples. To mimic the KCl deposition in real boilers, 24 hr exposures where KCl vapor condensed continuously onto samples were also performed. The corrosion attack of the studied materials increased significantly when KCl was present compared to the KCl‐free samples. For the KCl exposures, the corrosion attack drastically increased when a significant α‐Cr fraction was present. α‐Cr was either selectively attacked or dissolved through solid‐state diffusion and a layered build‐up of the outer external scale of K2CrO4 and chromia could be observed. For the in situ condensed KCl exposure, severe corrosion was observed already within the 24 hr exposure, indicating a higher corrosion rate compared with when KCl was predeposited.

KW - KCl-induced high-temperature corrosion

KW - Ni–Cr–Nb alloys

KW - Phase dissolution

KW - Selective attack

KW - α-Cr

U2 - 10.1002/maco.201810658

DO - 10.1002/maco.201810658

M3 - Journal article

VL - 70

SP - 1486

EP - 1506

JO - Materials and Corrosion

JF - Materials and Corrosion

SN - 0947-5117

IS - 8

ER -