Abstract
| Original language | English |
|---|---|
| Journal | Materials and Corrosion |
| Volume | 70 |
| Issue number | 8 |
| Pages (from-to) | 1486-1506 |
| ISSN | 0947-5117 |
| DOIs | |
| Publication status | Published - 2019 |
Keywords
- KCl-induced high-temperature corrosion
- Ni–Cr–Nb alloys
- Phase dissolution
- Selective attack
- α-Cr
Cite this
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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 journal › Journal article › Research › peer-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 -