Imaging diagnostics study on obliquely impacting plasma-sprayed particles near to the substrate

C.W. Kang, H.W. Ng, Ching Man Yu

Research output: Journal article publicationLiterature reviewAcademic researchpeer-review

22 Citations (Scopus)


Real time close-up images of in-flight particles plasma sprayed onto a substrate and in freestream condition (without substrate present) are captured. Besides the images, particle behavior in terms of temperature, velocity, and heading are measured by the SprayWatch particle imaging diagnostics system. The monitoring and measurement of particle behavior have been performed for substrates inclined at various angles to investigate the effect of the substrate on particle behavior. The close-up images show that particles propelled from the torch travel with high momentum and are not affected by the substrate and inclination angle. Quantitative analyses of the particle average velocity and heading data with and without the different inclined substrates also lead to similar conclusions. The particle velocity is resolved into tangential and normal velocity components parallel and perpendicular to the substrate, respectively. The tangential velocity component controls the degree of splat elongation into elliptical shape from the circular shape seen in perpendicular impact. This is of practical importance in industrial spraying of engineering components of complex curvatures. A higher tangential velocity component also implies that more powders are lost through rebounding and overspraying and thus reducing the deposition efficiency. The normal velocity component decreases when substrate inclination increases, which tends to weaken the coating adherence. © ASM International.
Original languageEnglish
Pages (from-to)118-130
Number of pages13
JournalJournal of Thermal Spray Technology
Issue number1
Publication statusPublished - 1 Mar 2006
Externally publishedYes


  • Imaging diagnostics
  • Inclined substrate
  • Particle parameters
  • SprayWatch system

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Materials Chemistry


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