Journal of Thermal Spray Technology

, Volume 16, Issue 5–6, pp 798–803 | Cite as

Effects of Impurity Content on the Sintering Characteristics of Plasma-Sprayed Zirconia

  • S. Paul
  • A. Cipitria
  • I.O. Golosnoy
  • L. Xie
  • M.R. Dorfman
  • T.W. Clyne

Yttria-stabilized zirconia powders, containing different levels of SiO2 and Al2O3, have been plasma sprayed onto metallic substrates. The coatings were detached from their substrates and a dilatometer was used to monitor the dimensional changes they exhibited during prolonged heat treatments. It was found that specimens containing higher levels of silica and alumina exhibited higher rates of linear contraction, in both in-plane and through-thickness directions. The in-plane stiffness and the through-thickness thermal conductivity were also measured after different heat treatments and these were found to increase at a greater rate for specimens with higher impurity (silica and alumina) levels. Changes in the pore architecture during heat treatments were studied using Mercury Intrusion Porosimetry (MIP). Fine scale porosity (<50 nm) was found to be sharply reduced even by relatively short heat treatments. This is correlated with improvements in inter-splat bonding and partial healing of intra-splat microcracks, which are responsible for the observed changes in stiffness and conductivity, as well as the dimensional changes.


apparent Young’s modulus plasma spray coatings porous material sintering thermal conductivity 


  1. 1.
    R.A. Miller Thermal Barrier Coatings for Aircraft Engines: History and Directions, J. Therm. Spray Technol., 1997, 6(1), 35-42CrossRefGoogle Scholar
  2. 2.
    M. Tamura, M. Takahashi, J. Ishii, K. Suzuki, M. Sato, K. Shimomura, Multilayered Thermal Barrier Coating for Land-Based Gas Turbines, J. Therm. Spray Technol., 1999, 8(1), 68-72CrossRefGoogle Scholar
  3. 3.
    L. Singheiser, R. Steinbrech, W.J. Quadakkers, R. Herzog, Failure Aspects of Thermal Barrier Coatings, Mater. High Temp., 2001, 18(4), 249-259Google Scholar
  4. 4.
    D. Stover, G. Pracht, H. Lehmann, M. Dietrich, J.E. Doring, R. Vassen, New Material Concepts for the Next Generation of Plasma Sprayed Thermal Barrier Coatings, J. Therm. Spray Technol., 2004, 13(1), 76-83Google Scholar
  5. 5.
    A.J. Allen, J. Ilavsky, G.G. Long, J.S. Wallace, C.C. Berndt, H. Herman, Microstructural Characterisation of Yttria-Stabilised Zirconia Plasma-Sprayed Deposits Using Multiple Small-Angle Neutron Scattering, Acta Mater., 2001, 49, 1661-1675CrossRefGoogle Scholar
  6. 6.
    A. Kulkarni, Z. Wang, T. Nakamura, S. Sampath, A. Goland, H. Herman, J. Allen, J. Ilavsky, G. Long, J. Frahm, R.W. Steinbrech, Comprehensive Microstructural Characterization and Predictive Property Modeling of Plasma-Sprayed Zirconia Coatings, Acta Mater., 2003, 51(9), 2457-2475CrossRefGoogle Scholar
  7. 7.
    A. Kulkarni, J. Gutleber, S. Sampath, A. Goland, W.B. Lindquist, H. Herman, A.J. Allen, B. Dowd, Studies of the Microstructure and Properties of Dense Ceramic Coatings Produced by High-Velocity Oxygen-Fuel Combustion Spraying, Mater. Sci. Eng. A – Struct., 2004, 369(1-2), 124-137CrossRefGoogle Scholar
  8. 8.
    P. Strunz, G. Schumacher, R. Vassen, A. Wiedenmann, In Situ SANS Study of Pore Microstructure in YSZ Thermal Barrier Coatings, Acta Mater., 2004, 52, 3305-3312CrossRefGoogle Scholar
  9. 9.
    T.A. Dobbins, A.J. Allen, J. Ilavsky, G.G. Long, P.R. Jemian, A. Kulkarni, H. Herman, Recent Development in the Characterization of Anizotropic Void Populations in Thermal Barrier Coatings Using Ultra-small Angle X-ray Scattering, Ceram. Eng. Sci Proc., 2003, 24(3), 517-524CrossRefGoogle Scholar
  10. 10.
    J. Ilavsky, C.C. Berndt, J. Karthikeyan, Mercury Intrusion Porosimetry of Plasma-Sprayed Ceramic, J. Mater. Sci., 1997, 32(15), 3925-3932CrossRefGoogle Scholar
  11. 11.
    H.E. Eaton, R.C. Novak, Sintering Studies of Plasma Sprayed Zirconia, Surf. Coat. Technol., 1987, 32, 227-236CrossRefGoogle Scholar
  12. 12.
    H.C. Chen, E. Pfender, J. Heberlein, Structural Changes in Plasma-Sprayed ZrO2 Coatings After Hot Isostatic Pressing, Thin Solid Films, 1997, 293(1-2), 227-235CrossRefGoogle Scholar
  13. 13.
    D.M. Zhu, R.A. Miller, Sintering and Creep Behaviour of Plasma-Sprayed Zirconia- and Hafnia-Based Thermal Barrier Coatings, Surf. Coat. Technol., 1998, 109(1-3), 114-120CrossRefGoogle Scholar
  14. 14.
    B. Siebert, C. Funke, R. Vassen, D. Stover, Changes in Porosity and Young’s Modulus Due to Sintering of Plasma Sprayed Thermal Barrier Coatings, J. Mater. Process Technol., 1999, 93, 217-223CrossRefGoogle Scholar
  15. 15.
    J. Ilavsky, G.G. Long, A.J. Allen, C.C. Berndt, Evolution of the Void Structure in Plasma-Sprayed YSZ Deposits During Heating, Mater. Sci. Eng., 1999, 272(1), 215-221CrossRefGoogle Scholar
  16. 16.
    J. Ilavsky, J.K. Stalick, J. Wallace, Thermal Spray Yttria-Stabilized Zirconia Phase Changes During Annealing, J. Therm. Spray Technol., 2001, 10(3), 491-501CrossRefGoogle Scholar
  17. 17.
    J.A. Thompson, T.W. Clyne, The Effect of Heat Treatment on the Stiffness of Zirconia Top Coats in Plasma-Sprayed TBCs, Acta Mater., 2001, 49(9), 1565-1575CrossRefGoogle Scholar
  18. 18.
    D. Stover, C. Funke, Directions of the Development of Thermal Barrier Coatings in Energy Applications, J. Mater. Process Technol., 1999, 93, 195-202CrossRefGoogle Scholar
  19. 19.
    V. Teixeira, M. Andritschky, H. Gruhn, W. Mallener, H.P. Buchkremer, D. Stoever, Failure of Physical Vapor Deposition/Plasma-Sprayed Thermal Barrier Coatings During Thermal Cycling, J. Therm. Spray Technol., 2000, 9(2), 191-197CrossRefGoogle Scholar
  20. 20.
    D.M. Zhu, R.A. Miller, Thermal Conductivity and Elastic Modulus Evolution of Thermal Barrier Coatings Under High Heat Flux Conditions, J. Therm. Spray Technol., 2000, 9, 175-180CrossRefGoogle Scholar
  21. 21.
    S.A. Tsipas, I.O. Golosnoy, R. Damani, T.W. Clyne, The Effect of a High Thermal Gradient on Sintering and Stiffening in the Top Coat of a Thermal Barrier Coating (TBC) System, J. Therm. Spray Technol., 2004, 13(3), 370-376CrossRefGoogle Scholar
  22. 22.
    S.R. Choi, D.M. Zhu, R.A. Miller, Effect of Sintering on Mechanical Properties of Plasma-Sprayed Zirconia-Based Thermal Barrier Coatings, J. Am. Ceram. Soc., 2005, 88(10), 2859-2867CrossRefGoogle Scholar
  23. 23.
    R. Hamacha, P. Fauchais, F. Nardou, Influence of Dopant on the Thermal Properties of Two Plasma-Sprayed Zirconia Coatings 1. Relationship Between Powder Characteristics and Coating Properties, J. Therm. Spray Technol., 1996, 5(4), 431-438CrossRefGoogle Scholar
  24. 24.
    S. Sodeoka, M. Suzuki, K. Ueno, H. Sakuramoto, T. Shibata, M. Ando, Thermal and Mechanical Properties of ZrO2-CeO2 Plasma-Sprayed Coatings, J. Therm. Spray Technol., 1997, 6(3), 361-367CrossRefGoogle Scholar
  25. 25.
    M.N. Rahaman, J.R. Gross, R.E. Dutton, H. Wang, Phase Stability, Sintering, and Thermal Conductivity of Plasma-Sprayed ZrO2-Gd2O3 Compositions for Potential Thermal Barrier Coating Applications, Acta Mater., 2006 54(6), 1615-1621CrossRefGoogle Scholar
  26. 26.
    B.Z. Janos, E. Lugscheider, P. Remer, Effect of Thermal Aging on the Erosion Resistance of Air Plasma Sprayed Ziconia Thermal Barrier Coating, Surf. Coat. Technol., 1999, 113(3), 278-285CrossRefGoogle Scholar
  27. 27.
    H.C. Chen, E. Pfender, J. Heberlein, Plasma-Sprayed ZrO2 Thermal Barrier Coatings Doped with an Appropriate Amount of SiO2, Thin Solid Films, 1998, 315(1-2), 159-169CrossRefGoogle Scholar
  28. 28.
    R. Vassen, N. Czech, W. Mallener, W. Stamm, D. Stoever, Influence of Impurity Content and Porosity of Plasma-Sprayed Yttria-Stabilized Zirconia Layers on the Sintering Behaviour, Surf. Coat. Technol., 2001, 141, 135-140CrossRefGoogle Scholar
  29. 29.
    K. Matsui, N. Ohmichi, M. Ohgai, N. Enomoto, J. Hojo, Sintering Kinetics at Constant Rates of Heating: Effect of Al2O3 on the Initial Sintering Stage of Fine Zirconia Powder, J. Am. Ceram. Soc., 2005, 88(12), 3346-3352CrossRefGoogle Scholar
  30. 30.
    S. Stemmer, J. Vleugels, O. Van Der Biest, Grain Boundary Segregation in High-Purity Yttria-Stabilized Tetragonal Zirconia Polygrystals (T-TZP), J. Eur. Ceram. Soc., 1998, 18, 1565-1570CrossRefGoogle Scholar
  31. 31.
    S. A. Tsipas, I. O. Golosnoy, R. Damani, T. W. Clyne, The Effect of a High Thermal Gradient on Sintering and Stiffening in the Top Coat of a Thermal Barrier Coating System, J. Therm. Spray Technol., 2004, 13(3), 370-376CrossRefGoogle Scholar
  32. 32.
    E.W. Washburn, Note on a Method of Determining the Distribution of Pore Sizes in a Porous Materials, Proc. Natl. Acad. Sci. USA., 1921, 7, 115-116CrossRefGoogle Scholar
  33. 33.
    M. Gustavsson, E. Karawacki, S.E. Gustafsson, Thermal Conductivity, Thermal Diffusivity, and Specific Heat of Thin Samples from Transient Measurements with Hot Disk Sensors, Rev. Sci. Inst., 1994, 65, 3856-3859CrossRefGoogle Scholar
  34. 34.
    M.F. Ashby, A First Report on Sintering Diagrams, Acta Metall. Mater., 1974, 22: 275-289CrossRefGoogle Scholar
  35. 35.
    S.M. Lakiza, L.M. Lopato, Stable and Metastable Phase Relations in the System Alumina-Zirconia-Yttria, J. Am. Ceram. Soc., 1997, 80(4), 893-902CrossRefGoogle Scholar
  36. 36.
    J. Van Brakel, S. Modry, M. Svata, Mercury Porosimetry: State of the Art, Powder Technol., 1981, 29, 1-12CrossRefGoogle Scholar
  37. 37.
    I.O. Golosnoy, S.A. Tsipas, T.W. Clyne, An Analytical Model for Simulation of Heat Flow in Plasma Sprayed Thermal Barrier Coatings, J. Therm. Spray Technol., 2005, 14(2), 205-214CrossRefGoogle Scholar

Copyright information

© ASM International 2007

Authors and Affiliations

  • S. Paul
    • 1
  • A. Cipitria
    • 1
  • I.O. Golosnoy
    • 1
  • L. Xie
    • 2
  • M.R. Dorfman
    • 2
  • T.W. Clyne
    • 1
  1. 1.Department of Materials Science & MetallurgyCambridge UniversityCambridgeUK
  2. 2.Sulzer Metco (US) Inc.New YorkUSA

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