Abstract
Laboratory testing of selected chromia-forming alloys was performed to
rank the materials and gain further knowledge on the mechanism of
KCl-induced high temperature corrosion. The investigated alloys were
stainless steels EN1.4021, EN1.4057, EN1.4521, TP347H (coarse-grained),
TP347HFG (fine-grained), Sanicro 28 and the nickel-based alloys 625, 263
and C276. Exposure was performed at 600 °C for 168 h in flowing N2(g)+5%O2(g)+15% H2O(g)
(vol.%). Samples were covered with KCl powder prior to exposure. A
salt-free exposure was also performed for comparison. Corrosion
morphology and products were studied with scanning electron microscopy
(SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray
diffractometry (XRD). It was observed that in the salt-free exposure,
stainless steels TP347H (coarse-grained) and EN1.4521 failed to form a
thin protective oxide layer compared to the oxide formed on the other
alloys. In the presence of solid KCl, all the alloys showed significant
corrosion. Measurement of corrosion extent indicated that alloys
EN1.4057, Sanicro 28 and 625 show a better performance compared to the
industrial state of the art material TP347HFG under laboratory
conditions. An additional test was performed with KCl vapor in static
air for the same duration and at the same temperature. This was
undertaken to investigate the role of the vapor phase and revealed that
KCl vapor at 600 °C can initiate attack.
Original language | English |
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Journal | Materials and Corrosion |
Volume | 66 |
Issue number | 12 |
Pages (from-to) | 1414-1429 |
ISSN | 0947-5117 |
DOIs | |
Publication status | Published - 2015 |
Keywords
- Al2O3
- Anatase
- Coatings
- Interfaces
- Photoabsorption
- Photocatalytic activity
- Photoelectrochemistry
- TiO2