Influence of Preoxidation on High-Temperature Corrosion of a FeCrAl Alloy Under Conditions Relevant to Biomass Firing

Sunday Chukwudi Okoro*, Melanie Montgomery, Flemming Jappe Frandsen, Karen Pantleon

*Corresponding author for this work

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Abstract

Preoxidation of a commercial FeCrAl alloy (Kanthal APM) was evaluated as a surface modification approach to reduce alkali chloride-induced corrosion during biomass firing in power plants. Samples of the alloy preoxidized at 900 °C in O2 or O2 + 10 vol% H2O, and at 1100 °C in O2, were coated with KCl and exposed at 560 °C to a gas mixture comprising of 12 vol% CO2, 6 vol% O2, 3 vol% H2O, 400 ppmv HCl and 60 ppmv SO2. The oxide formed at 1100 °C showed no reactivity with the corrosive species. By contrast, all samples preoxidized at 900 °C suffered severe attack, resulting in formation of Fe-, Cr- and Al-containing corrosion products in a heterogeneous morphology, similar to non-preoxidized samples. The observed differences with respect to the degree of corrosion attack on the preoxidized samples are discussed in terms of the composition and thickness of the different types of Al2O3 layers obtained by the preoxidation treatment.
Original languageEnglish
JournalOxidation of Metals
Volume89
Issue number1-2
Pages (from-to)99–122
ISSN0030-770X
DOIs
Publication statusPublished - 2018

Keywords

  • FeCrAl alloy
  • Preoxidation
  • High-temperature corrosion
  • KCI
  • Chlorination

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