Modeling of pyrolytic laser‐assisted chemical vapor deposition: Mass transfer and kinetic effects influencing the shape of the deposit

1988 ◽  
Vol 63 (1) ◽  
pp. 198-206 ◽  
Author(s):  
D. C. Skouby ◽  
K. F. Jensen
Keyword(s):  
Mass Transfer ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Kinetic Effects

Mass transfer and kinetics of the chemical vapor deposition of SiC onto fibers

1998 ◽  
Vol 13 (8) ◽  
pp. 2251-2261 ◽  
Author(s):  
W. Jack Lackey ◽  
Sundar Vaidyaraman ◽  
Bruce N. Beckloff ◽  
Thomas S. Moss III ◽  
John S. Lewis
Keyword(s):  
Mass Transfer ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
Total Flow ◽  
A Value ◽  
Factor Expression ◽  
Kinetics Of ◽  
Best Fit

An internally consistent set of data was generated for the chemical vapor deposition (CVD) of SiC from methyltrichlorosilane (MTS) and H2 at atmospheric pressure. A moving fiber tow was used as the substrate. Coating rates between 0.3 and 3.7 µm/min and deposition efficiencies between 24 and 48% were obtained for MTS and H2 flow rates in the range 30 to 200 cm3/min and 300 to 2000 cm3/min, respectively. The data were analyzed and found to be best fit under a mass transfer regime. Based on this fit, a value of the constant in the Chilton–Colburn j factor expression for a moving fiber tow was estimated to be 2.74 × 10−6 with a standard deviation of 3.2 × 10−7. The efficiency of the reaction was found to decrease with increases in the total flow rate, indicating that the effect of the decreased residence time of reagents in the reactor was larger than the increase in the mass transfer coefficient. Finally, a comparison between the efficiencies for a stationary and a moving tow revealed that the moving tow had a higher efficiency, possibly due to a disruption of the boundary layer by the tow motion or due to the decrease in the canning of the moving tow.

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