Abstract
This paper is the continuation of previous work,[1] in which plasma fluctuations were shown to produce significant time-dependent variations in the in-flight particle temperature and velocity, as well as in the number of detected particles. In this paper, the impact of the plasma fluctuations on the coating microstructure and deposition efficiency is demonstrated. Alumina coatings and deposition efficiencies, obtained with two sets of spray conditions showing similar in-flight particle conditions (velocity and temperature) with the DPV-2000 but displaying very different voltage fluctuations, are compared. The coating produced in the less stable plasma condition (C-I) is found to be more porous and contains a larger number of unmelted particles than the other coating produced in more steady plasma conditions (C-II). Moreover, condition C-I yields a significantly lower deposition efficiency. Such large discrepancies must be traced back to the physical characteristics of the particle jet. Laser illumination of the particle jet is used to probe particles too cold to be detected by pyrometric means. Cold particles are found in a much larger proportion in C-I than in C-II. They are ascribed to particles that are injected when the plasma is in a low enthalpy state. Periodic time-dependent variations in the in-flight characteristics of cold and hot particles, synchronous with the voltage fluctuations, are revealed.
Similar content being viewed by others
References
J.F. Bisson, B. Gauthier, and C. Moreau: “Effect of Plasma Fluctuations on In-Flight Particle Parameters,” J. Therm. Spray Technol., 2003, 12(1), pp. 38–43.
G. Barbezat, F. Folio, C. Coddet and G. Montavon: “The Benefit of the PROTAL Process on the Adhesion of Thermal Sprayed Coatings” in Thermal Spray: Surface Engineering via Applied Research, C.C. Berndt, ed., ASM International, Materials Park, OH, 2000, pp. 57–62.
E.J. Kubel, Jr.: “Powders Dictate Thermal Spray Coating Properties,” Adv. Mater. Processes, 1990, 12, pp. 24–32.
J. Zierhut, P. Haslbeck, K.D. Landes, and G. Barbezat: “Triplex-An Innovative Three-Cathode Plasma Torch” in Thermal Spray: Meeting the Challenges of the 21st Century, C. Coddet, ed., ASM International, Materials Park, OH, 1998, pp. 1375–79.
G. Reiners, H. Kreye, and R. Sewetzke: “Properties and Characterization of Thermal Spray Coatings” in Thermal Spray: Meeting the Challenges of the 21st Century, C. Coddet, ed., ASM International, Materials Park, OH, 1998, pp. 629–34.
C. Moreau: “Towards a Better Control of Thermal Spray Processes” in Thermal Spray: Meeting the Challenges of the 21st Century, C. Coddet, ed., ASM International, Materials Park, OH, 1998, pp. 1681–93.
C. Moreau, P. Gougeon, M. Lamontagne, V. Lacasse, G. Vaudreuil, and P. Cielo: “On-Line Control of the Plasma Spraying Process by Monitoring the Temperature, Velocity, and Trajectory of the In-flight Particles” in Thermal Spray Industrial Applications, C.C. Berndt and S. Sampath, ed., ASM International, Materials Park, OH, 1994, pp. 431–36.
W.D. Swank, J.R. Fincke and D.C. Haggard: “A Particle Temperature Sensor for Monitoring and Control of the Thermal Spray Process” in Thermal Spray: Science and Technology, C.C. Berndt and S. Sampath, ed., ASM International, Materials Park, OH, 1995, pp. 111–16.
J. Vattulainen, J. Knuutila, T. Lehtinen, T. Mäntylä, and R. Hernberg: “In-Flight Particle Concentration and Velocity Measurements in Thermal Spraying Using Non-Intensified CCD Camera” in Thermal Spray: Meeting the Challenge of the 21st Century, C. Coddet, ed., ASM International, Materials Park, OH, 1998, pp. 767–72.
M. Vardelle, P. Fauchais, A. Vardelle, and A.C. Léger: “Thermal Spray, Influence of the Variation of Plasma Torch Parameters on Particle Melting and Solidification” in A United Forum for Scientific and Technological Advances, C.C. Berndt, ed., ASM International, Materials Park, OH, 1997, pp. 535–42.
M. Prystay, P. Gougeon, and C. Moreau: “Structure of Plasma-Sprayed Zirconia Coatings Tailored by Controlling the Temperature and Velocity of the Sprayed Particles,” J. of Thermal Spray Technol., 2001, 10(1), pp. 67–75.
J. Madjeski: “Droplet Impact With a Cold Surface,” Int. J. Heat Mass Transfer. 1983, 26, pp. 1095–98.
J. Blain, F. Nadeau, L. Pouliot, C. Moreau, et al.: “Integrated Infrared Sensor System For On-Line Diagnostics of Particles Under Thermal Spraying Conditions,” Surf. Eng., 1997, 13, pp. 420–24.
M. Pristay, P. Gougeon, and C. Moreau: “Structure of Plasma-Sprayed Zirconia Coatings Tailored by Controlling the Temperature and Velocity of the Sprayed Particles,” J. Thermal Spray Technol., 10(1), 2001, pp. 67–82.
Z. Duan and J. Heberlein: “Anode Boundary Layer Effects in Plasma Spray Torches” in Thermal Spray: Surface Engineering via Applied Research, C.C. Berndt, ed., ASM International, Materials Park, OH, 2000, pp. 1–7.
P. Gougeon, C. Moreau, V. Lacasse, M. Lamontagne, et al.: “A New Sensor for On-Line Diagnostics of Particles Under Thermal Spraying Conditions,” Adv. Process. Tech. Particulate Materials, 6, Metal Powder Industries Federation, Princeton, NJ, 1994, pp. 199–210.
L. Leblanc, C. Moreau, P. Gougeon, and J. Xi: “Long Term Stability of Plasma Spraying: Study on the Evolution of the In-Flight Particle State, Coating Microstructure, Voltage and Acoustic Signatures” in Tagungsband Conference Proceedings, E. Lugscheider and P.A. Kammer, ed., Pub. DVS Deutscher Verband für Schweissen, Germany, 1999, pp. 306–11.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bisson, J.F., Moreau, C. Effect of direct-current plasma fluctuations on in-flight particle parameters: Part II. J Therm Spray Tech 12, 258–264 (2003). https://doi.org/10.1361/105996303770348375
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1361/105996303770348375