Journal of Thermal Spray Technology

, Volume 14, Issue 3, pp 354–361 | Cite as

Photographing impact of molten molybdenum particles in a plasma spray

  • N. Z. Mehdizadeh
  • M. Lamontagne
  • C. Moreau
  • S. Chandra
  • J. Mostaghimi
Reviewed Papers


Plasma-sprayed molten molybdenum particles (∼40 µm in diameter) were photographed impinging at high velocity (∼140 m/s) on a glass substrate at room temperature. An optical sensor detected thermal radiation emitted by a droplet as it approached the substrate and activated a time delay unit. After a selected time interval, an Nd:YAG laser was triggered, emitting a 5 ns pulse that provided illumination for a charge-coupled device (CCD) camera to photograph the impacting droplet through a long-range microscope. By varying the delay before pulsing the laser, different stages of droplet deformation were recorded. Impacting droplets spread into a thin circular film that ruptured and broke into small fragments. An optical detector recording thermal radiation from the impacting droplet gave a signal that increased as the droplet spread out, reached a maximum when the liquid film began to rupture, and decreased as portions of the droplet recoiled because of surface tension and then flew out of view of the photodetector.


droplet particle impact plasma spray splashing splat 


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Copyright information

© ASM International 2005

Authors and Affiliations

  • N. Z. Mehdizadeh
    • 1
  • M. Lamontagne
    • 1
  • C. Moreau
    • 2
  • S. Chandra
    • 2
  • J. Mostaghimi
    • 2
  1. 1.National Research Council of CanadaIndustrial Materials InstituteBouchervilleCanada
  2. 2.Centre for Advanced Coating TechnologiesUniversity of TorontoTorontoCanada

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