Investigation of interfacial properties of atmospheric plasma sprayed thermal barrier coatings with four-point bending and computed tomography technique

Y. Zhao, A. Shinmi, X. Zhao, P. J. Withers, S. Van Boxel, N. Markocsan, P. Nylen, P. Xiao

    Research output: Contribution to journalArticlepeer-review

    Abstract

    A modified four-point bending test has been employed to investigate the interfacial toughness of atmospheric plasma sprayed (APS) yttria stabilised zirconia (YSZ) thermal barrier coatings (TBCs) after isothermal heat treatments at 1150°C. The delamination of the TBCs occurred mainly within the TBC, several to tens of microns above the interface between the TBC and bond coat. X-ray diffraction analysis revealed that the TBC was mainly tetragonal in structure with a small amount of the monoclinic phase. The calculated energy release rate increased from ~50J/m -2 for as-sprayed TBCs to ~120J/m -2 for the TBCs exposed at 1150°C for 200h with a loading phase angle about 42°. This may be attributed to the sintering of the TBC. X-ray micro-tomography was used to track in 3D the evolution of the TBC microstructure non-destructively at a single location as a function of thermal exposure time. This revealed how various types of imperfections develop near the interface after exposure. The 3D interface was reconstructed and showed no significant change in the interfacial roughness after thermal exposure. © 2012 Elsevier B.V.
    Original languageEnglish
    Pages (from-to)4922-4929
    Number of pages7
    JournalSurface and Coatings Technology
    Volume206
    Issue number23
    DOIs
    Publication statusPublished - 15 Jul 2012

    Keywords

    • Computed tomography
    • Four-point bending
    • Interfacial toughness
    • Plasma sprayed
    • Thermal barrier coatings

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