Influence of heat exposure time on isothermal degradation of plasma sprayed CoNiCrAlY coatings

D. Seo, K. Ogawa, M. Tanno, T. Shoji, S. Murata

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

In this work, the thermal degradation behavior of selected CoNiCrAlY coatings has been studied. Emphasis was placed upon the change of oxygen content, porosity, surface roughness, and oxidation behavior. The results show that the isothermal degradation of coatings was considerably influenced by the heat exposure time and powder particle distribution. The values of oxygen content, surface roughness, and TGO scales converge sharply into the stable extremes at the initial stage of heat exposure. The particle size has an effect on the oxygen content in as-sprayed coatings. After heat exposure, the difference of the oxygen content on coating deposited using between the smaller and larger particle was decreased. The cross-sectional porosity decreased at Stage IP, increased at Stage IIP, and then decreased again. These could be due to the sintering effect at Stage IP. The surface roughness decreased up to Stage IR, but over Stage IR, surface roughness was kept in relatively fixed value or increased slightly. The TGO thickness growth rate and parabolic oxidation rate constant are influenced by the surface roughness of coatings.

Original languageEnglish
Pages (from-to)7952-7960
Number of pages9
JournalSurface and Coatings Technology
Volume201
Issue number18
DOIs
Publication statusPublished - 2007 Jun 25

Keywords

  • CoNiCrAlY
  • Heat exposure time
  • Isothermal degradation
  • Vacuum plasma spray (VPS)

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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