Experimental and numerical life prediction of thermally cycled thermal barrier coatings

Research output: Contribution to journalReview article

Abstract

This article addresses the predominant degradation modes and life prediction of a plasma-sprayed thermal barrier coating (TBC). The studied TBC system consists of an air-plasm a-sprayed bond coat and an air-plasma-sprayed, yttria partially stabilized zirconia top layer on a conventional Hastelloy X substrate. Thermal shock tests of air-sprayed TBC and pre-oxidized TBC specimens were conducted under different burner flame conditions at Volvo Aero Corporation (Trollhiittan, Sweden). Finite element models were used to simulate the thermal shock tests. Transient temperature distributions and thermal mismatch stresses in different layers of the coatings during thermal cycling were calculated. The roughness of the interface between the ceramic top coat and the bond coat was modeled through an ideally sinusoidal wavy surface. Bond coat oxidation was simulated through adding an aluminum oxide layer between the ceramic top coat and the bond coat. The calculated stresses indicated that interfacial delamination cracks, initiated in the ceramic top coat at the peak of the asperity of the interface, together with surface cracking, are the main reasons for coating failure. A phenomenological life prediction model for the coating was proposed. This model is accurate within a factor of

Details

Authors
  • Yan Liu
  • Christer Persson
  • J Wigren
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Engineering

Keywords

  • thermal shock tests, stress relaxation, prediction model, life, in-plane stress range, bond coat oxidation, finite element method
Original languageEnglish
Pages (from-to)415-424
JournalJournal of Thermal Spray Technology
Volume13
Issue number3
Publication statusPublished - 2004
Publication categoryResearch
Peer-reviewedYes