Hot corrosion of nickel-base alloys by alkali-containing sulfate deposits

C. Leyens, I. G. Wright, B. A. Pint

Research output: Contribution to journalConference articlepeer-review

8 Scopus citations

Abstract

In this study, a hot corrosion scenario relevant to biomass-derived fuel-fired advanced land-based gas turbines is considered. The testing procedures take account of the different corrosive species (low sulfur, potassium-rich salts) and transient salt deposition conditions expected. These differ from those typically used to simulate Type I hot corrosion. A simplified cyclic hot corrosion test was applied, subjecting (K, Na)SO4-coated, cast nickel-base alloys, nickel aluminides and a model electron beam physical vapor deposition (EB-PVD) thermal barrier coating (TBC) system to 1-h cycles at 950°C in flowing oxygen. Contaminant flux rate, salt recoating frequency and deposit removal/retention are important parameters to be controlled during testing. Cr rather than Pt and other precious metals such as Ir, Pd and Ru improves hot corrosion resistance of cast nickel aluminides. Practical implications for TBC systems are that molten deposits will be expected to primarily affect the bond coat by hot corrosion attack rather than degrade the ceramic top coating, thus indicating that both oxidation- and hot corrosion-resistant bond coats are needed to enable safe TBC operation.

Original languageEnglish
Pages (from-to)571-578
Number of pages8
JournalMaterials Science Forum
Volume369-372
Issue numberII
DOIs
StatePublished - 2001
Externally publishedYes
Event5th International Symposium on High Temperature Corrosion - Les Embiez, France
Duration: May 22 2000May 26 2000

Keywords

  • Biomass-derived fuels
  • Hot corrosion
  • Nickel aluminides
  • Nickel-base alloys
  • Thermal barrier coating

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