The effect of oxygen source on the reaction mechanism of potassium chloride-induced high-temperature corrosion

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Juho Lehmusto, Mikael Bergelin, Daniel Lindberg, Jyrki Juhanoja
Förläggare: NACE International
Publiceringsår: 2018
Tidskrift: CORROSION
Tidskriftsakronym: CORROSION
Volym: 74
Nummer: 12
Artikelns första sida, sidnummer: 1431
Artikelns sista sida, sidnummer: 1445
eISSN: 1938-159X


Abstrakt

The role of two oxygen sources, air and water vapor, in the initiation of KCl-induced high-temperature corrosion was addressed with three different commercial alloys typically used in power plants. The focus was on the initiation of the corrosion reaction, so an exposure time of 120 minutes at 540°C was used under flowing conditions. The possible selectivity of oxygen in the corrosion reaction was studied by using two different stable oxygen isotopes, 16O in air and 18O in water vapor, and identifying the isotopes after the reaction with ToF-SIMS. In addition, the surface morphologies were imaged with SEM-EDX and the depth profiles mapped with XPS. Despite the chemical composition of the tested alloys, the alloy surface appears to favor a direct reaction with oxygen from water vapor, when available. On the contrary, the oxygen from air is more involved in reaction(s) forming potassium chromate (K2CrO4). The formation of K2CrO4 provides further evidence of the role of potassium in the initiation of KCl-induced high-temperature corrosion.


Nyckelord

Biomass combustion, High-temperature corrosion, Low alloy steel, Nickel-based alloy, Potassium chloride, Stable oxygen isotopes, Stainless steel, time-of-flight secondary ion mass spectrometry

Senast uppdaterad 2019-15-10 vid 03:10