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Journal of Thermal Spray Technology

, Volume 15, Issue 4, pp 811–816 | Cite as

Characterizations and hot corrosion resistance of Cr3C2-NiCr coating on Ni-base superalloys in an aggressive environment

  • T. S. Sidhu
  • S. Prakash
  • R. D. Agrawal
Reviewed Papers

Abstract

In the current study, Cr3C2-NiCr coating was deposited on the Ni-base superalloys by using high velocity oxyfuel (HVOF) process for high temperature corrosive environment applications. Optical microscopy (OM), x-ray diffraction (XRD), scanning electron microscopy/energy-dispersive analysis (SEM/EDAX), microhardness tester, and electro probe microanalyzer (EMPA) techniques were used to characterize the coating with regard to coating thickness, porosity, microhardness, and microstructure. The thermogravimetric technique was used to establish kinetics of corrosion. The hot corrosion behaviors of the bare and Cr3C2-NiCr coated superalloys were studied after exposure to aggressive environment of Na2SO4-60% V2O5 salt mixture at 900 °C under cyclic conditions. The structure of the as-sprayed Cr3C2-NiCr coating mainly consisted of γ-nickel solid solution along with minor phases of Cr7C3 and Cr2O3. Coating has porosity less than 1.5% and microhardness in the range of 850–900 Hv (Vickers hardness). Some inclusions, unmelted and semimelted powder particles were observed in the structure of the coatings. The Cr3C2-NiCr coating has imparted necessary resistance to hot corrosion, which has been attributed to the formation of oxides of nickel and chromium, and spinel of nickel-chromium.

Keywords

Cr3C2-NiCr high velocity oxyfuel hot corrosion Ni-Based superalloys protective coating 

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References

  1. 1.
    T.S. Sidhu, S. Prakash, and R.D. Agrawal, State of the Art of HVOF Coating Investigation—A Review,Mar. Technol. Soc. J., 2005,39(2), p 55–66CrossRefGoogle Scholar
  2. 2.
    N. Eliaz, G. Shemesh, and R.M. Latanision, Hot Corrosion in Gas Turbine Components,Eng. Fail. Anal., 2002,9, p 31–43CrossRefGoogle Scholar
  3. 3.
    Y.S. Hwang and R.A. Rapp, Thermochemistry and Solubilities of Oxides in Sodium Sulfate-Vanadate Solutions,Corrosion, 1989,45, p 933–937Google Scholar
  4. 4.
    S.N. Tiwari, “Investigations on Hot Corrosion of Some Fe-, Ni- and Co-Base Superalloy in Na2SO4-V2O5 Environment under Cyclic Conditions,” Ph. D. Thesis, Met. Mat. Eng. Dept., University of Roorkee, Roorkee, India, 1997Google Scholar
  5. 5.
    B.Q. Wang and K. Luer, The erosion-oxidation behavior of HVOF Cr3C2-NiCr Cermet Coating,Wear, 1994,174, p 177–185CrossRefGoogle Scholar
  6. 6.
    T.S. Sidhu, S. Prakash, and R.D. Agrawal, Characterisation of NiCr Wire Coating on Ni- and Fe- Based Superalloy by HVOF Process,Surf. Coat. Technol., 2006,200, p 5542–5549CrossRefGoogle Scholar
  7. 7.
    T.S. Sidhu, S. Prakash, and R.D. Agrawal, Characterisation of HVOF sprayed NiCrBSi Coatings on Ni- and Fe-Based Superalloys and Evaluation of Cyclic Oxidation Behaviour of Some Ni-Based Superalloys in Molten Salt Environment,Thin Solid Films, 2006,515, p 95–105CrossRefGoogle Scholar
  8. 8.
    T.S. Sidhu, S. Prakash, and R.D. Agrawal, Hot Corrosion Behaviour of HVOF-sprayed NiCrBSi Coatings on Ni- and Fe-Based Superalloys in Na2SO4-V2O5 Environment at 900 °C,Acta Mater., 2006,54, p 773–784CrossRefGoogle Scholar
  9. 9.
    W.-M. Zhao, Y. Wang, T. Han, K.-Y. Wu, and J. Xue, Electrochemical Evaluation of Corrosion Resistance of NiCrBSi Coatings Deposited by HVOF,Surf. Coat. Technol., 2004,183, p 118–125CrossRefGoogle Scholar
  10. 10.
    “Standard Test Method for Apparent Porosity in Cemented Carbides,” B276-05,Annual Book of ASTM Standards, ASTMGoogle Scholar
  11. 11.
    J.M. Guilemany, J. Fernandez, J. Delgado, A.V. Benedetti, and F. Climent, Effects of Thickness Coating on the Electrochemical Behaviour of Thermal Spray Cr3C2-NiCr Coatings,Surf. Coat. Technol., 2002,153(2–3), p 107–113CrossRefGoogle Scholar
  12. 12.
    P.H. Suegama, C.S. Fugivara, A.V. Benedetti, J. Fernandez, J. Delgado, and J.M. Guilemany, Electrochemical Behaviour of Thermally Sprayed Cr3C2-NiCr Coatings in 0.5 M H2SO4 Media,J. Appl. Chem., 2002,32, p 1287–1295Google Scholar
  13. 13.
    T. Sundararajan, S. Kuroda, and F. Abe, Steam Oxidation Studies on 50Ni-50Cr HVOF Coatings on 9Cr-1Mo Steel: Change in Structure and Morphology Across the Coating/Substrate Interface,Mater. Trans., 2004,45(4), p 1299–1305CrossRefGoogle Scholar
  14. 14.
    V.H. Hidalgo, J.B. Varela, J.M. Calle, and A.C. Menendez, Characterisation of NiCr Flame and Plasma Sprayed Coatings for Use in High Temperature Regions of Boilers,Surface Eng., 2000,16(2), p 137–142CrossRefGoogle Scholar
  15. 15.
    C. Verdon, A. Karimi, and J.-L. Martin, A Study of High Velocity Oxy-Fuel Thermally Sprayed Tungsten Carbide Based Coatings. Part 1: Microstructures,Mater. Sci. Eng. A, 1998,246, p 11–14CrossRefGoogle Scholar
  16. 16.
    P. Vuoristo, K. Niemi, A. Makela, and T. Mantyla, Abrasion and Erosion Wear Resistance of Cr3C2-NiCr Coatings Prepared by Plasma, Detonation and High-Velocity Oxyfuel Spraying,Proc. 7th National Thermal Spray Conf., June 20–24, 1994 (Boston, MA), p 121–126Google Scholar
  17. 17.
    A.H. Dent, A.J. Horlock, D.G. McCartney, and S.J. Harris, Microstructural Characterisation of a Ni-Cr-B-C Based Alloy Coating Produced by High Velocity Oxy-Fuel Thermal Spraying,Surf. Coat. Technol., 2001,139, p 244–250CrossRefGoogle Scholar
  18. 18.
    C. Moreau, P. Cielo, M. Lamontagne, S. Dallaire, J.C. Krapez, and M. Vardelle, Temperature Evolution of Plasma-Sprayed Niobium Particles Impacting on a Substrate,Surf. Coat. Technol., 1991,46, p 173–181CrossRefGoogle Scholar
  19. 19.
    G.A. Kolta, I.F. Hewaidy, and N.S. Felix, Reactions Between Sodium Sulphate and Vanadium Pentoxide,Thermochim. Acta, 1972,4, p 151–164Google Scholar

Copyright information

© ASM International 2006

Authors and Affiliations

  1. 1.Metallurgical and Materials Engineering DepartmentIndian Institute of Technology RoorkeeRoorkeeIndia

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