Laser Thermal Gradient Testing and Fracture Mechanics Study of a Thermal Barrier Coating

  • Yingsang Wu
  • Pei-feng HsuEmail author
  • Yao Wang
  • Mary Helen McCay
  • D. Edward Croy
  • David Moreno
  • Lei He
  • Chao Wang
  • Hongqi Zhang
Peer Reviewed


It is critical for thermal barrier coating (TBC) development that a testing method be used to understand the potential and limitation of a coating’s durability and integrity under gas turbine engine operating conditions. To this end, a TBC-coated button is tested using a laser high-heat flux facility. The ceramic coating is ZrO2-8 wt.% Y2O3 applied via the air plasma spraying process on top of a NiCoCrAlY bond coating and an Inconel alloy 617 substrate button of 25.4 mm diameter. The coated button is subject to precisely controlled laser heating on the top side (1150 °C) and a temperature gradient of 63.9 °C/mm through the button overall thickness. The coated button lasts 160.9 h or 570 cycles of laser heating. The void fraction change before and after the test, the thermal conductivity change during the laser test and the failure assessment are presented. After the test, significant horizontal cracks exist in the top coating close to the thermally grown oxide (TGO) layer and near the button center. Based on the cracks and the TGO layer geometry, the stress intensity factor and strain energy release rate are computed. The combined experimental and computational approach can lead to a TBC lifetime model.


crack analysis energy release rate finite element analysis laser thermal gradient test thermal barrier coating thermally grown oxides yttria-stabilized zirconia 

List of Symbols


Air plasma spraying


Bond coating


Specific heat


Young’s modulus


Full-width at half-maximum


Strain energy release rate


Stress intensity factor


Normalized thermal conductivity


Thermal conductivity


Scanning electron microscope


Substrate superalloy


Thermal barrier coatings


Top coating


Thermally grown oxides




Hot side or top side of button temperature


Cold side or bottom side of button substrate temperature


Yttria stabilized zirconia


Coefficient of thermal expansion




Poisson’s ratio



The authors wish to acknowledge the support of laser high-heat flux testing by Shanghai Electric Gas Turbine Co. Ltd. The support of the numerical study is provided by Florida Institute of Technology.


  1. 1.
    V. Viswanathan, G. Dwivedi, and S. Sampath, Multilayer, Multi-materials Thermal Barrier Coating Systems: Design, Synthesis, and Performance Assessment, J. Am. Ceram. Soc., 2015, 98(6), p 1769-1777CrossRefGoogle Scholar
  2. 2.
    M.J. Smith, J. Scheibel, D. Classen, S. Paschke, S. Elbel, K. Fick, and D. Carlson, Thermal Barrier Coating Validation Testing for Industrial Gas Turbine Combustion Hardware, in ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, June 16-20, 2014 (Dusseldorf, Germany), International Gas Turbine Institute, 2014, GT2014-26359Google Scholar
  3. 3.
    A. Feuerstein, J. Knapp, T. Taylor, A. Ashary, A. Bolcavage, and N. Hitchman, Technical and Economical Aspects of Current Thermal Barrier Coating Systems for Gas Turbine Engines by Thermal Spray and EBPVD: a Review, J. Thermal Spray Technol., 2008, 17(2), p 199-213. CrossRefGoogle Scholar
  4. 4.
  5. 5.
    R.A. Miller, and C.E. Lowell, Failure Mechanisms of Thermal Barrier Coatings Exposed to Elevated Temperatures. Thin Solid Films 95, 265–273 (1982). Also NASA TM-1982-82905Google Scholar
  6. 6.
    A.H. Bartlett and R.D. Maschio, Failure Mechanisms of a Zirconia-8 wt% Yttria Thermal Barrier Coating, J. Am. Ceram. Soc., 1995, 78, p 1018-1024CrossRefGoogle Scholar
  7. 7.
    N.M. Yanar, The Failure of Thermal Barrier Coatings at Elevated Temperatures, Ph.D. Dissertation, Univ of Pittsburgh, 2004Google Scholar
  8. 8.
    R. Eriksson, and K.R. Jonnalagadda, A Study on Crack Configurations in Thermal Barrier Coatings, in ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, June 26-30, 2017 (Charlotte, USA), International Gas Turbine Institute, 2017, GT2017-63610Google Scholar
  9. 9.
    J.P. Feist, P.Y. Sollazzo, C. Pilgrim, and J.R. Nicholls, Operation of a Burner Rig for Thermal Gradient Cycling of Thermal Barrier Coatings, in ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, June 16-20, 2014 (Dusseldorf, Germany), International Gas Turbine Institute, 2014, GT2014-26325Google Scholar
  10. 10.
    A.M. Kanury, Chapter 8 Flames in Premixed Gases, Introduction to Combustion Phenomena, 3rd ed., Gordon & Breach, New York, 1982Google Scholar
  11. 11.
    M.H. McCay, P.-f. Hsu, D.E. Croy, D. Moreno, and M. Zhang, The Fabrication, High Heat Flux Testing, and Failure Analysis of Thermal Barrier Coatings for Power Generation Gas Turbines, in ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, June 26-30, 2017 (Charlotte, USA), International Gas Turbine Institute, 2017, GT2017-63683Google Scholar
  12. 12.
    D. Zhu and R.A. Miller, Thermal Conductivity and Elastic Modulus Evolution of Thermal Barrier Coatings under High Heat Flux Conditions, J. Thermal Spray Technology, 2000, 9(2), p 175-180CrossRefGoogle Scholar
  13. 13.
    D. Zhu, and R.A. Miller, “Thermal Conductivity of Advanced Ceramic Thermal Barrier Coatings Determined by a Steady-State Laser Heat-Flux Approach,” NASA TM-2004- 213040 & ARL–TR–3262, Cleveland, Ohio, July 2004Google Scholar
  14. 14.
    R.S. Lima, B.R. Marple, and P. Marcoux, Thermal Gradient Behavior of TBCs Subjected to a Laser Gradient Test Rig: simulating an Air-to-Air Combat Flight, J. Thermal Spray Technol., 2016, 25(1–2), p 282-290. CrossRefGoogle Scholar
  15. 15.
    LabVIEW, National Instruments, 11500 N Mopac Expwy, Austin, TX 78759, USAGoogle Scholar
  16. 16.
    The Ircon Modline 3, IRCON, Inc., Santa Cruz, CA 95060, USAGoogle Scholar
  17. 17.
    J.I. Eldridge and C.M. Spuckler, Determination of Scattering and Absorption Coefficients for Plasma-Sprayed Yttria-Stabilized Zirconia Thermal Barrier Coatings at Elevated Temperatures, J. Am. Ceram. Soc., 2009, 92(10), p 2276-2285CrossRefGoogle Scholar
  18. 18.
    Mikron Model MI-SQ5, LumaSense Technologies, Inc., 3301 Leonard Court, Santa Clara, CA 95054, USAGoogle Scholar
  19. 19.
    MATLAB, MathWorks, 1 Apple Hill Drive, Natick, MA 01760, USAGoogle Scholar
  20. 20.
    Standard Test Methods for Determining Area Percentage Porosity in Thermal Sprayed Coating, E2109-01, ASTM Standards, ASTM, 2014Google Scholar
  21. 21.
    M.A. Helminiak, N.M. Yanar, F.S. Pettie, T.A. Taylor, and G.H. Meier, The Behavior of High-Purity, Low-Density Air Plasma Sprayed Thermal Barrier Coatings, Surf. Coat. Technol., 2009, 204, p 793-796CrossRefGoogle Scholar
  22. 22.
    G.C. Chang, W. Phucharoen, and R.A. Miller, Behavior of Thermal Barrier Coatings for Advanced Gas Turbine Blades, Surf. Coat. Technol., 1987, 30(1), p 13-28CrossRefGoogle Scholar
  23. 23.
    C.H. Hsueh and E.R. Fuller, Residual Stresses in Thermal Barrier Coatings: Effect of Interface Asperity Curvature/Height and Oxide Thickness, Mat. Sci. Eng. A, 2000, 283(1–2), p 46-55CrossRefGoogle Scholar
  24. 24.
    C.H. Hsueh and E.R. Fuller, Analytical Modeling of Oxide Thickness Effects on Residual Stresses in Thermal Barrier Coatings, Scripta Mat, 2000, 42(8), p 781-787CrossRefGoogle Scholar
  25. 25.
    M. Gupta, Design of Thermal Barrier Coatings: A Modelling Approach, Springer, Berlin, 2015CrossRefGoogle Scholar
  26. 26.
    J. Aktaa, K. Sfar, and R. Munz, Assessment of TBC Systems Failure Mechanisms using a Fracture Mechanics Approach, Acta Mat., 2006, 53(16), p 4399-4413CrossRefGoogle Scholar
  27. 27.
    M. Martena, D. Botto, P. Fino, S. Sabbadini, M.M. Gola, and C. Badini, Modeling of TBC System Failure: Stress Distribution as a Function of TGO Thickness and Thermal Expansion Mismatch, Engr Fail. Anal., 2006, 13(3), p 409-426CrossRefGoogle Scholar
  28. 28.
    M. Gupta, K. Skogsberg, and P. Nylén, Influence of Topcoat-Bondcoat Interface Roughness on Stresses and Lifetime in Thermal Barrier Coatings, J. Thermal Spray Technol., 2014, 23(1–2), p 170-181. CrossRefGoogle Scholar
  29. 29.
    M. Gupta, R. Eriksson, U. Sand, and P. Nylén, A Diffusion-Based Oxide Layer Growth Model Using Real Interface Roughness in Thermal Barrier Coatings for Lifetime Assessment, Surf. Coat. Technol., 2015, 271(15), p 181-191CrossRefGoogle Scholar
  30. 30.
    ANSYS, Inc., 2600 ANSYS Drive, Canonsburg, PA 15317, USAGoogle Scholar
  31. 31.
    Properties: Alumina-Aluminium Oxide-Al2O3—A Refractory Ceramic Oxide. Accessed 31 Jan 2019
  32. 32.
    H. Zeng, J. Fang, W. Xu, Z. Zhao, and L. Wang, Thermomechanical Modeling of A Single Splat Solidification in Plasma Spraying, J. Achiev. Mater. Manuf. Eng., 2006, 18(1–2), p 327-330Google Scholar
  33. 33.
    K. Kim, D. Lee, and H. Cho, Lifetime Prediction of Film Cooling Systems with and without Thermal Barrier Coating, Int. J. Fluid Mach. Syst., 2010, 3(2), p 204-210CrossRefGoogle Scholar
  34. 34.
    Zirconia—Stabilized with Yttria—Online Catalogue Source—Supplier of Research Materials in Small Quantities—Goodfellow. Accessed 31 Jan 2019
  35. 35.
    G.M. Smith, M. Resnick, B. Kjellman, J. Wigren, G. Dwivedi, and S. Sampath, Orientation-dependent mechanical and thermal properties of plasma-sprayed ceramics, J. Am. Ceram. Soc., 2018, 101, p 2471-2481CrossRefGoogle Scholar
  36. 36.
    S.R. Choi, D. Zhu, and R.A. Miller, Effect of Sintering on Mechanical and Physical Properties of Plasma-Sprayed Thermal Barrier Coatings, NASA TM-2004-212625, April 2004Google Scholar
  37. 37.
    R. Vaßen, S. Giesen, and D. Stover, Lifetime of Plasma Sprayed Thermal Barrier Coatings: Comparison of Numerical and Experimental Results, J. Thermal Spray Tech., 2009, 18(5–6), p 835-845CrossRefGoogle Scholar
  38. 38.
    Y.S. Wu, P.-f. Hsu, Y. Wang, and M.H. McCay, Finite Element Analysis of Cracks in the Thermal Barrier Coatings, 2019, under preparation.Google Scholar

Copyright information

© ASM International 2019

Authors and Affiliations

  • Yingsang Wu
    • 1
  • Pei-feng Hsu
    • 1
    Email author
  • Yao Wang
    • 1
  • Mary Helen McCay
    • 1
    • 2
  • D. Edward Croy
    • 2
  • David Moreno
    • 2
  • Lei He
    • 3
  • Chao Wang
    • 3
  • Hongqi Zhang
    • 3
  1. 1.Mechanical Engineering ProgramFlorida Institute of TechnologyMelbourneUSA
  2. 2.National Center for Hydrogen ResearchFlorida Institute of TechnologyMelbourneUSA
  3. 3.Gas Turbine InstituteShanghai Electric Gas Turbine Co. Ltd.ShanghaiChina

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