Mechanistic understanding for degraded thermal barrier coatings

Kazuhiro Ogawa, Tetsuo Shoji, Hisahiko Aoki, Norio Fujita, Taiji Torigoe

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

A two-layer plasma sprayed thermal barrier coating on Ni base superalloy substrate was characterized. The coating was comprised of an inner layer of MCrAlY bond coating and an outer layer of 8wt% yttria stabilized zirconia (YSZ) thermal barrier coating (TBC). After aging, the reaction layer at interface between YSZ and MCrAlY was observed. The reaction layer had two different contrast layers in the SEM images. One was black which was closer to MCrAlY and the other was gray which was closer to YSZ. The thickness of both layers increased with aging. Also countless porosities at the gray layer and microcrack at YSZ were observed. Most of the macrocrack grew through the porosities. From this viewpoint one may say that the mechanism of macrocrack formation is a deterioration of adhesion which was accompanied by an increase of the porosities or the microcrack.

Original languageEnglish
Pages (from-to)1370-1376
Number of pages7
JournalNihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
Volume66
Issue number647
DOIs
Publication statusPublished - 2000 Jan 1

Keywords

  • Aging
  • Ceramics
  • Crack propagation
  • Kirkendall porosity
  • Laminated construction
  • Macrocrack
  • Microcrack
  • Reaction layer
  • Thermal barrier coating
  • Thermal stress

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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