Simulation of Thermal Plasma Spraying of Partially Molten Ceramics: Effect of Carrier Gas on Particle Deposition and Phase Change Phenomena

2000 ◽  
Author(s):  
I. Ahmed ◽  
T. L. Bergman

Abstract A 3D simulation of the thermal plasma spraying process is reported. In particular, the effect of the radial injection of a carrier gas is taken into account for a dilute spray. The thermal history of powder particles of different sizes is predicted. It is shown that introduction of a carrier gas can lead to a significant modification of the plasma jet, and can have an effect on the thermal histories of the injected particles. The study is motivated by the processing of non-traditional materials, specifically nanostructured ceramics.

2000 ◽  
Vol 123 (1) ◽  
pp. 188-196 ◽  
Author(s):  
I. Ahmed ◽  
T. L. Bergman

A three-dimensional simulation of the thermal plasma spraying process is reported. In particular, the effect of the radial injection of a carrier gas is taken into account for a dilute spray. The thermal history of powder particles of different sizes is predicted. It is shown that introduction of a carrier gas can lead to a significant modification of the plasma jet, and can have an effect on the thermal histories of the injected particles. The study is motivated by the processing of non-traditional materials, specifically nanostructured ceramics.


2005 ◽  
Vol 475-479 ◽  
pp. 2883-2886
Author(s):  
Heji Huang ◽  
Keisuke Eguchi ◽  
Makoto Kambara ◽  
Toyonobu Yoshida

With a newly established 300kW twin hybrid plasma spraying system, a peculiar layered composite zirconia coating was successfully deposited. The coating is consisting of splats and dendritic columns, which come from thermal plasma spraying and thermal plasma PVD, respectively. A 120µm-thick composite coating was deposited in 10 minutes at the corresponding growth rate of 100µm/min, if the rotation of the substrates is considered. The microstructure of such composite coatings has been characterized using a variety of microscopic techniques as part of a process optimization study.


Vacuum ◽  
2005 ◽  
Vol 77 (2) ◽  
pp. 145-150 ◽  
Author(s):  
Zahir Salhi ◽  
Didier Klein ◽  
Patrick Gougeon ◽  
Christian Coddet

Author(s):  
R.L. Williamson ◽  
J.R. Fincke ◽  
C.H. Chang

Abstract Computational modeling is used to systematically examine many of the sources of statistical variance in particle parameters during thermal plasma spraying. Using the computer program LAVA, a steady-state plasma jet typical of a commercial torch at normal operating conditions, is first developed. Then, assuming a single particle composition (ZrO2) and injection location, real world complexity (e.g., turbulent dispersion, particle size and density, injection velocity and direction, etc.) is introduced "one phenomenon at a time" to distinguish and characterize its effect and enable comparisons of separate effects. A final calculation then considers all phenomena simultaneously, to enable further comparisons. Investigating each phenomenon separately provides valuable insight into particle behavior. For the typical plasma jet and injection conditions considered, particle dispersion in the injection direction is most significantly affected by (in order of decreasing importance): particle size distribution, injection velocity distribution, turbulence, and injection direction distribution or particle density distribution. Only the distribution of injection directions and turbulence affect dispersion normal to the injection direction, and are of similar magnitude in this study. With regards to particle velocity and temperature, particle size is clearly the dominant effect.


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