Abstract
A commercial torch has been modified to introduce an additional anti-vortex and shroud gas flow to counter the detrimental effects brought about by the vortex plasma gas flow which is used to stabilize the cathode arc attachment and to increase the anode life. Deposition efficiency and coating quality are used as criteria to judge the modified versus the nonmodified torch. High-speed videography and computerized image analysis systems are used to determine the particle trajectories, velocities, and the plasma jet geometry. The results show that the additional anti-vortex and shroud gas flow to the torch can keep the particles closer to the torch axis and reduce the amount of entrainment of cold air into the plasma jet. The consequence is that deposition efficiency and coating quality are substantially improved.
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References
S. Malmberg, “Analysis of the plasma jet structure, particle motion, and coating quality during DC plasma spraying”, Ph.D. Thesis, Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, 1994.
S. Malmberg and J. Heberlein,J. Therm. Spray Technol. 2, 339–343 (1993).
S. Malmberg, J. Heberlein, and E. Pfender, Proceedings of the Sixth National Thermal Spray Conference, Boston, Massachusetts, June 20–24, 1994.
S. Malmberg, K. Leung, J. Heberlein, and E. Pfender, Proceedings of the 14th International Thermal Spray Conference, Kobe, Japan, May 22–26, 1995.
E. Pfender,Thin Solid Films 238, 228–241 (1994).
E. Pfender, J. Fincke, and R. Spores,Plasma Chem. Plasma Process. 11, 529–543 (1991).
K. Leung, “Modification on a plasma torch nozzle to counter the negative effects of the vortex flow”, M. S. Thesis, Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, 1995.
J. R. Fincke, and W. D. Swank, “Thermal Spray Research and Applications”, Proceedings of the Third National Thermal Spray Conference, May 20–25, 1990, Long Beach, California, p. 39.
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Chen, H.C., Pfender, E. & Heberlein, J. Improvement of plasma spraying efficiency and coating quality. Plasma Chem Plasma Process 17, 93–105 (1997). https://doi.org/10.1007/BF02766824
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DOI: https://doi.org/10.1007/BF02766824