Oxide scale formation and microstructural degradation of conventional, Pt- and Pt/Ir-modified NiAl diffusion coatings during thermocyclic exposure at 1100 °C

C. Oskay*, M. C. Galetz, H. Murakami

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

The microstructural degradation of Pt- and Pt/Ir-modified NiAl coatings during thermocyclic exposure at 1100 °C was investigated. Detailed microstructural investigation revealed the different beneficial effects of Pt and Ir. Platinum was found to be active in the healing mechanism of the oxide scale, whereas Ir incorporation provided an obstruction to interdiffusion. Oxidized surface morphologies exhibited the formation of a dense alumina scale on top of the PtAl coating, whereas Al-depletion in the NiAl coating was accelerated due to scale spallation and interfacial void formation. Additionally, Pt inward- and Ni outward diffusion was substantially reduced in the Ir-containing coatings.

Original languageEnglish
Pages (from-to)313-327
Number of pages15
JournalCorrosion Science
Volume144
DOIs
Publication statusPublished - 2018 Nov

Keywords

  • EPMA
  • Intermetallics
  • Oxidation
  • SEM
  • Thermal cycling
  • X-ray diffraction

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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