Influence of Nozzle Throat Cross Section on Microstructure and Properties of Cold Sprayed Coatings

  • Naveen Manhar ChavanEmail author
  • M. Vinod Kumar
  • P. Sudharshan Phani
  • Prita Pant
  • G. Sundararajan
Peer Reviewed


In cold spray, the coating microstructure and properties are strongly dependent on the particle velocity before impact. Particle velocity for a given powder and thereby energy consumption during the process are mainly dependent on process pressure, process temperature and nozzle geometry. Of the several aspects of nozzle geometry, the throat cross section determines the mass flow rate and thereby the total energy for the process. While reduction in throat cross section reduces the energy consumption per unit time of operation, viscous boundary layer effects become significant at smaller throat cross sections causing reduction in gas and particle velocities. This work explores the effect of throat cross section on the particle velocity distribution and thereby the coating microstructure and properties. Computational fluid dynamic simulations are also carried out to rationalize the observations. Our results corroborate the theoretical findings of previous work based on nozzle exit or throat width h to divergent length L ratio, i.e., h/L. Moreover, it was found that nozzles with lower throat cross section (h/L < 0.02) consume significantly higher energy per unit mass of coating due to longer coating duration and significant boundary layer effects in addition to yielding relatively poorer coating property.


cold spray copper deposition efficiency nozzle optical diagnostics 



The authors would like to thank the Director, ARCI, for granting permission to publish this article. The authors would also like to acknowledge the support extended by Mr. Vikas Reddy, GTP and Mr. B. Vignesh, JRF, for help during experimentation and modeling. One of the authors would like to thank Dr. S. Kumar for useful discussions.


  1. 1.
    T. Stoltenhoff, H. Kreye, and H.J. Richter, An Analysis of the Cold Spray Process and Its Coatings, J. Therm. Spray Technol., 2002, 11(4), p 542-550CrossRefGoogle Scholar
  2. 2.
    H. Assadi, T. Schmidt, H. Richter, J.O. Kilemann, K. Binder, F. Gartner, T. Klassen, and H. Kreye, On Parameter Selection in Cold Spraying, J. Therm. Spray Technol., 2011, 20(6), p 1161-1176CrossRefGoogle Scholar
  3. 3.
    G. Bae, J. Jang, and C. Lee, Correlation of Particle Impact Conditions with Bonding, Nanocrystal Formation and Mechanical Properties in Kinetic Sprayed Nickel, Acta Mater., 2012, 60, p 3524-3535CrossRefGoogle Scholar
  4. 4.
    L. Venkatesh, N.M. Chavan, and G. Sundararajan, The Influence of Powder Particle Velocity and Microstructure on the Properties of Cold Sprayed Copper Coatings, J. Therm. Spray Technol., 2011, 20(5), p 1009-1021CrossRefGoogle Scholar
  5. 5.
    P.S. Phani, D.S. Rao, S.V. Joshi, and G. Sundararajan, Effect of Process Parameters and Heat Treatments on Properties of Cold Sprayed Copper Coatings, J. Therm. Spray Technol., 2007, 16, p 245-434CrossRefGoogle Scholar
  6. 6.
    N.M. Chavan, M. Ramakrishna, P.S. Phani, D.S. Rao, and G. Sundararajan, The Influence of Process Parameters and Heat Treatment on the Properties of Cold Sprayed Silver Coatings, Surf. Coat. Technol., 2011, 205, p 4798-4807CrossRefGoogle Scholar
  7. 7.
    A.P. Alkhimov, V.F. Kosarev, and S.V. Klinkov, The Features of Cold Spray Nozzle Design, J. Therm. Spray Technol., 2001, 10(2), p 375-381CrossRefGoogle Scholar
  8. 8.
    B. Jodoin, Cold Spray Nozzle Mach Number Limitation, J. Therm. Spray Technol., 2002, 11(4), p 496-507CrossRefGoogle Scholar
  9. 9.
    S. Yin, X.F. Wang, and W.Y. Li, Computational Analysis of the Effect of Nozzle Cross-Section Shape on Gas Flow and Particle Acceleration in Cold Spraying, Surf. Coat. Technol., 2011, 205, p 2970-2977CrossRefGoogle Scholar
  10. 10.
    W.Y. Li, H. Liao, G. Douchy, and C. Coddet, Optimal Design of a Cold Spray Nozzle by Numerical Analysis of Particle Velocity and Experimental Validation with 316L Stainless Steel Powder, Mater. Des., 2007, 28, p 2129-2137CrossRefGoogle Scholar
  11. 11.
    V. Varadarajan and P. Mohanty, Design and Optimization of Rectangular Cold Spray Nozzle: Radial Injection Angle, Expansion Ratio and Traverse Speed Surf, Coat. Technol., 2017, 316, p 246-254CrossRefGoogle Scholar
  12. 12.
    R. Lupoi, Current Design and Performance of Cold Spray Nozzles: Experimental and Numerical Observations on Deposition Efficiency and Particle Velocity, Surf. Eng., 2014, 30(5), p p316-p322CrossRefGoogle Scholar
  13. 13.
    Y. Li, Y. Hamada, K. Otobe, and T. Ando, A Method to Predict the Thickness of Poorly-Bonded Material Along Spray and Spray-Layer Boundaries in Cold Spray Deposition, J Therm. Spray Technol., 2017, 26, p 350-359CrossRefGoogle Scholar
  14. 14.
    D. MacDonald, S. Leblanc-Robert, R. Fernandez, A. Farjam, and B. Jodoin, Effect of Nozzle Material on Downstream Lateral Injection Cold Spray Performance, J Therm. Spray Technol., 2016, 25(6), p 1149-1157CrossRefGoogle Scholar
  15. 15.
    V.K. Champagne, D.J. Helfritch, S.P.G. Dinavahi, and P.F. Leyman, Theoretical and Experimental Particle Velocity in Cold Spray, J Therm. Spray Technol., 2011, 20, p 425-431CrossRefGoogle Scholar
  16. 16.
    Alexey Sova, Sergey Klinkov, Vladimir Kosarev, Nikolay Ryashin, and Igor Smurov, Preliminary Study on Deposition of Aluminium and Copper Powders by Cold Spray Micro Nozzle Using Helium, Surf. Coat. Technol., 2013, 220, p p98-101CrossRefGoogle Scholar
  17. 17.
    S. Buhl, P. Breuninger, and S. Antonyuk, Optimization of a Laval Nozzle for Energy-Efficient Cold Spraying of Microparticles, Mater. Manuf. Process., 2018, 33(2), p p115-p122CrossRefGoogle Scholar
  18. 18.
    A. Sova, I. Smurov, M. Doubenskaia, and P. Petrovskiy, Deposition of Aluminium Powder by Cold Spray Micronozzle, Int. J. Adv. Manuf. Technol., 2018, 95, p 3745-3752CrossRefGoogle Scholar
  19. 19.
    D. Helfritch, O. Stier, and J. Villafuerte, Cold spray economics, Modern Cold Spray- Materials, Process and Applications, J. Villafuerte, Ed., Springer, Switzerland, 2015, p 377-402CrossRefGoogle Scholar
  20. 20.
    G. Sundararajan, N.M. Chavan, G. Sivakumar, and P.S. Phani, Evaluation of Parameters for Assessment of Inter-Splat Bond Strength in Cold-Sprayed Coatings, J. Therm. Spray Technol., 2010, 19(6), p 1255-1266CrossRefGoogle Scholar
  21. 21.
    S.P. Pardhasaradhi, V. Venkatachalapathy, S.V. Joshi, and S. Govindan, Optical Diagnostics Study of Gas Particle Transport Phenomena in Cold Gas Dynamic Spraying and Comparison with Model Predictions, J. Therm. Spray Technol., 2008, 17(4), p p551-p563CrossRefGoogle Scholar

Copyright information

© ASM International 2019

Authors and Affiliations

  • Naveen Manhar Chavan
    • 1
    Email author
  • M. Vinod Kumar
    • 1
  • P. Sudharshan Phani
    • 1
  • Prita Pant
    • 2
  • G. Sundararajan
    • 3
  1. 1.International Advanced Research Centre for Powder Metallurgy and New Materials, ARCIHyderabadIndia
  2. 2.Indian Institute of Technology BombayMumbaiIndia
  3. 3.Indian Institute of Technology MadrasChennaiIndia

Personalised recommendations