Journal of Thermal Spray Technology

, Volume 27, Issue 7, pp 1076–1089 | Cite as

Fracture Toughness of Thermal Spray Ceramics: Measurement Techniques and Processing Dependence

  • Gregory M. SmithEmail author
  • Adam Smith
  • Sanjay Sampath
Peer Reviewed


Fracture toughness measurements are critical for materials design and characterization but can be difficult to perform on overlay coatings due to a range of geometric factors and substrate constraints. Thermal spray (TS) coatings bring additional complications to measurement interpretation due to their defected, anisotropic structures. Toughness of free-standing coatings has been studied in the past, and literature results indicate promise in measurement with a range of methods. One of these, single-edge, notched beam (SENB) method offers a straight forward approach for measuring fracture toughness and lends itself well for use with TS coatings. In this work, SENB method is used with deliberate modifications to specific parameters of the test specimens, namely free-standing thickness, notch depth, notch sharpness, and heat treatment state, to ascertain the impact of these modifications on the measurement results for air plasma spray Al2O3. Additionally, two methods adapted from the literature, a modified adhesion method and a tensile elongation method, are evaluated for use with three different Al2O3 coatings, including by air plasma spray, flame spray, and high velocity oxy-fuel processes. Results indicate good correlation between SENB and the modified methods for all three coating variants and give insight into the orientation-dependent toughness properties of TS coatings.


cracking fracture mechanical properties microstructure tensile bond strength 



The authors would like to sincerely thank the Industrial Consortium for Thermal Spray Technology at Stony Brook University for their ongoing support of the Center’s research efforts, as well as Evan Brooke for his help in modeling stress concentrations with varying notch depths.


  1. 1.
    J. Shackelford and R.H. Doremus, Ceramic and Glass Materials: Structure, Properties and Processing, Springer, 2008, p 1-202  Google Scholar
  2. 2.
    M.F. Ashby, Materials Selection in Mechanical Design, Butterworth-Heinemann, Oxford, 2011Google Scholar
  3. 3.
    R.O. Ritchie, The Conflicts Between Strength and Toughness, Nat. Mater., 2011, 10, p 817CrossRefGoogle Scholar
  4. 4.
    F. Bouville, E. Maire, S. Meille, B. Van de Moortèle, A.J. Stevenson, and S. Deville, Strong, Tough and Stiff Bioinspired Ceramics From Brittle Constituents, Nat. Mater., 2014, 13(5), p 508-514CrossRefGoogle Scholar
  5. 5.
    F.W. Zok and C.G. Levi, Mechanical Properties of Porous-Matrix Ceramic Composites, Adv. Eng. Mater., 2001, 3(1-2), p 15-23CrossRefGoogle Scholar
  6. 6.
    G.D. Quinn and R.C. Bradt, On the Vickers Indentation Fracture Toughness Test, J. Am. Ceram. Soc., 2007, 90(3), p 673-680CrossRefGoogle Scholar
  7. 7.
    N.P. Padture, M. Gell, and E.H. Jordan, Thermal Barrier Coatings for Gas-Turbine Engine Applications, Science, 2002, 296(5566), p 280-284CrossRefGoogle Scholar
  8. 8.
    S.R. Choi, D. Zhu, and R.A. Miller, Fracture Behavior Under Mixed-Mode Loading of Ceramic Plasma-Sprayed Thermal Barrier Coatings at Ambient and Elevated Temperatures, Eng. Fract. Mech., 2005, 72(13), p 2144-2158CrossRefGoogle Scholar
  9. 9.
    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(6), p 2471-2481CrossRefGoogle Scholar
  10. 10.
    G. Dwivedi, V. Viswanathan, S. Sampath, A. Shyam, and E. Lara-Curzio, Fracture Toughness of Plasma-Sprayed Thermal Barrier Ceramics: Influence of Processing, Microstructure, and Thermal Aging, J. Am. Ceram. Soc., 2014, 97(9), p 2736-2744CrossRefGoogle Scholar
  11. 11.
    E.M. Donohue, N.R. Philips, M.R. Begley, and C.G. Levi, Thermal Barrier Coating Toughness: Measurement and Identification of a Bridging Mechanism Enabled by Segmented Microstructure, Mater. Sci. Eng. A, 2013, 564, p 324-330CrossRefGoogle Scholar
  12. 12.
    G. Dwivedi, K. Flynn, M. Resnick, S. Sampath, and A. Gouldstone, Bioinspired Hybrid Materials from Spray-Formed Ceramic Templates, Adv. Mater., 2015, 27(19), p 3073-3078CrossRefGoogle Scholar
  13. 13.
    G.D. Quinn and J.J. Swab, Fracture Toughness of Glasses as Measured by the SCF and SEPB Methods, J. Eur. Ceram. Soc., 2017, 37(14), p 4243-4257CrossRefGoogle Scholar
  14. 14.
    R.J. Damani and E.H. Lutz, Microstructure, Strength and Fracture Characteristics of a Free-Standing Plasma-Sprayed Alumina, J. Eur. Ceram. Soc., 1997, 17(11), p 1351-1359CrossRefGoogle Scholar
  15. 15.
    Standard Test Method for Measurement of Fracture Toughness, E 1820, ASTM International 2017Google Scholar
  16. 16.
    Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature, C 1421, ASTM International 2018Google Scholar
  17. 17.
    Standard Test Method for Adhesion or Cohesion Strength of Thermal Spray Coatings, C 633, ASTM International 2013Google Scholar
  18. 18.
    X. Luo, G.M. Smith, and S. Sampath, On the Interplay Between Adhesion Strength and Tensile Properties of Thermal Spray Coated Laminates—Part I: High Velocity Thermal Spray Coatings, J. Therm. Spray Technol., 2018, 27(3), p 296-307CrossRefGoogle Scholar
  19. 19.
    G. Qian, T. Nakamura, C.C. Berndt, and S.H. Leigh, Tensile Toughness Test and High Temperature Fracture Analysis of Thermal Barrier Coatings, Acta Mater., 1997, 45(4), p 1767-1784CrossRefGoogle Scholar
  20. 20.
    M. Watanabe, S. Kuroda, K. Yokoyama, T. Inoue, and Y. Gotoh, Modified Tensile Adhesion Test for Evaluation of Interfacial Toughness of HVOF Sprayed Coatings, Surf. Coat. Technol., 2008, 202(9), p 1746-1752CrossRefGoogle Scholar
  21. 21.
    Y. Okajima, T. Nakamura, and S. Sampath, Effect of Powder Injection on the Interfacial Fracture Toughness of Plasma-Sprayed Zirconia, J. Therm. Spray Technol., 2013, 22(2), p 166-174CrossRefGoogle Scholar
  22. 22.
    A. Vackel, T. Nakamura, and S. Sampath, Mechanical Behavior of Spray-Coated Metallic Laminates, J. Therm. Spray Technol., 2016, 25(5), p 1009-1019CrossRefGoogle Scholar
  23. 23.
    G.M. Smith, O. Higgins, and S. Sampath, In-situ Observation of Strain and Cracking in Coated Laminates by Digital Image Correlation, Surf. Coat. Technol., 2017, 328, p 211-218CrossRefGoogle Scholar
  24. 24.
    G.M. Smith and S. Sampath, Sustainability of Metal Structures via Spray-Clad Remanufacturing, JOM, 2018, 70(4), p 512-520CrossRefGoogle Scholar
  25. 25.
    T. Ganne, J. Crépin, S. Serror, and A. Zaoui, Cracking Behaviour of PVD Tungsten Coatings Deposited on Steel Substrates: The Influence of Film Thickness, Acta Mater., 2002, 50, p 4149-4163CrossRefGoogle Scholar
  26. 26.
    M.S. Hu and A.G. Evans, The Cracking and Decohesion of Thin Films on Ductile Substrates, Acta Mater., 1989, 37(3), p 917-925CrossRefGoogle Scholar
  27. 27.
    S. Kuroda, Y. Tashiro, H. Yumoto, S. Taira, H. Fukanuma, and S. Tobe, Peening Action and Residual Stresses in High-Velocity Oxygen Fuel Thermal Spraying of 316L Stainless Steel, J. Therm. Spray Technol., 2001, 10(2), p 367-374CrossRefGoogle Scholar
  28. 28.
    J. Matejicek and S. Sampath, In Situ Measurement of Residual Stresses and Elastic Moduli in Thermal Sprayed Coatings: Part 1: Apparatus and Analysis, Acta Mater., 2003, 51(3), p 863-872CrossRefGoogle Scholar
  29. 29.
    A. Valarezo and S. Sampath, An Integrated Assessment of Process-Microstructure-Property Relationships for Thermal-Sprayed NiCr Coatings, J. Therm. Spray Technol., 2011, 20(6), p 1244-1258CrossRefGoogle Scholar
  30. 30.
    W.C. Oliver and G.M. Pharr, An Improved Technique for Determining Hardness and Elastic Modulus Using Load and Displacement Sensing Indentation Experiments, J. Mater. Res., 1992, 7(6), p 1564-1583CrossRefGoogle Scholar
  31. 31.
    G.M. Smith, M. Resnick, K. Flynn, G. Dwivedi, and S. Sampath, Nature Inspired, Multi-Functional, Damage Tolerant Thermal Spray Coatings, Surf. Coat. Technol., 2016, 297, p 43-50CrossRefGoogle Scholar
  32. 32.
    J. Kubler, Fracture Toughness of Ceramics Using the Sevnb Method: Preliminary Results, Proceedings of the 21st Annual Conference on Composites, Advanced Ceramics, Materials, and StructuresB: Ceramic Engineering and Science, ed., J.P. Singh, 1997Google Scholar
  33. 33.
    L. Vargas-Gonzalez, R.F. Speyer, and J. Campbell, Flexural Strength, Fracture Toughness, and Hardness of Silicon Carbide and Boron Carbide Armor Ceramics, Int. J. Appl. Ceram. Technol., 2010, 7(5), p 643-651CrossRefGoogle Scholar
  34. 34.
    G.A. Gogotsi, Fracture Toughness of Ceramics and Ceramic Composites, Ceram. Int., 2003, 29(7), p 777-784CrossRefGoogle Scholar
  35. 35.
    R. Damani, R. Gstrein, and R. Danzer, Critical Notch-Root Radius Effect in SENB-S Fracture Toughness Testing, J. Eur. Ceram. Soc., 1996, 16(7), p 695-702CrossRefGoogle Scholar
  36. 36.
    R.G. Munro, Material Properties of a Sintered α-SiC, J. Phys. Chem. Ref. Data, 1997, 26(5), p 1195-1203CrossRefGoogle Scholar
  37. 37.
    M.G. Mueller, V. Pejchal, G. Žagar, A. Singh, M. Cantoni, and A. Mortensen, Fracture Toughness Testing of Nanocrystalline Alumina and Fused Quartz using Chevron-Notched Microbeams, Acta Mater., 2015, 86, p 385-395CrossRefGoogle Scholar
  38. 38.
    R.E. Grimes, G.P. Kelkar, L. Guazzone, and K.W. White, Elevated-Temperature R-Curve Behavior of a Polycrystalline Alumina, J. Am. Ceram. Soc., 1990, 73(5), p 1399-1404CrossRefGoogle Scholar
  39. 39.
    R.F. Krause, Rising Fracture Toughness from the Bending Strength of Indented Alumina Beams, J. Am. Ceram. Soc., 1988, 71(5), p 338-343CrossRefGoogle Scholar
  40. 40.
    P. Auerkari, Mechanical and Physical Properties of Engineering Alumina Ceramics, Technical Research Centre of Finland, VTT Tiedotteita - Meddelanden - Res. Notes, 1996, 1792, p 1–26Google Scholar
  41. 41.
    G. Žagar, V. Pejchal, M.G. Mueller, L. Michelet, and A. Mortensen, Fracture Toughness Measurement in Fused Quartz Using Triangular Chevron-Notched Micro-cantilevers, Scr. Mater., 2016, 112, p 132-135CrossRefGoogle Scholar
  42. 42.
    S.M. Wiederhorn, Fracture Surface Energy of Glass, J. Am. Ceram. Soc., 1969, 52(2), p 99-105CrossRefGoogle Scholar
  43. 43.
    Y. Tan, J.P. Longtin, S. Sampath, and H. Wang, Effect of the Starting Microstructure on the Thermal Properties of As-Sprayed and Thermally Exposed Plasma-Sprayed YSZ Coatings, J. Am. Ceram. Soc., 2009, 92(3), p 710-716CrossRefGoogle Scholar
  44. 44.
    W. Chi, S. Sampath, and H. Wang, Ambient and High-Temperature Thermal Conductivity of Thermal Sprayed Coatings, J. Therm. Spray Technol., 2006, 15(4), p 773-778CrossRefGoogle Scholar
  45. 45.
    W. Chi, S. Sampath, and H. Wang, Microstructure-Thermal Conductivity Relationships for Plasma-Sprayed Yttria-Stabilized Zirconia Coatings, J. Therm. Spray Technol., 2008, 91(8), p 2636-2645Google Scholar
  46. 46.
    Z. Wang, A. Kulkarni, S. Deshpande, T. Nakamura, and H. Herman, Effects of Pores and Interfaces on Effective Properties of Plasma Sprayed Zirconia Coatings, Acta Mater., 2003, 51(18), p 5319-5334CrossRefGoogle Scholar
  47. 47.
    E. García, M.I. Osendi, and P. Miranzo, Thermal Diffusivity of Porous Cordierite Ceramic Burners, J. Appl. Phys., 2002, 92(5), p 2346-2349CrossRefGoogle Scholar
  48. 48.
    R. Musalek, J. Matejicek, M. Vilemova, and O. Kovarik, Non-linear Mechanical Behavior of Plasma Sprayed Alumina Under Mechanical and Thermal Loading, J. Therm. Spray Technol., 2010, 19(1-2), p 422-428CrossRefGoogle Scholar
  49. 49.
    R. Mušálek, O. Kovářík, and J. Matějíček, In-situ Observation of Crack Propagation in Thermally Sprayed Coatings, Surf. Coat. Technol., 2010, 205(7), p 1807-1811CrossRefGoogle Scholar
  50. 50.
    D. Zhu and R.A. Miller, Sintering and Creep Behavior of Plasma-Sprayed Zirconia- and Hafnia-Based Thermal Barrier Coatings, Surf. Coat. Technol., 1998, 108-109, p 114-120CrossRefGoogle Scholar
  51. 51.
    Y. Liu, T. Nakamura, G. Dwivedi, A. Valarezo, and S. Sampath, Anelastic Behavior of Plasma-Sprayed Zirconia Coatings, J. Am. Ceram. Soc., 2008, 91(12), p 4036-4043CrossRefGoogle Scholar
  52. 52.
    G. Dwivedi, T. Nakamura, and S. Sampath, Controlled Introduction of Anelasticity in Plasma-Sprayed Ceramics, J. Am. Ceram. Soc., 2011, 94(s1), p s104-s111CrossRefGoogle Scholar

Copyright information

© ASM International 2018

Authors and Affiliations

  1. 1.Center for Thermal Spray ResearchStony Brook UniversityStony BrookUSA

Personalised recommendations