Chemistry and kinetics of chemical vapour deposition of pyrocarbon -: VII.: Confirmation of the influence of the substrate surface area/reactor volume ratio

Carbon deposition from a methane-hydrogen mixture (p(CH4) = 17.5 kPa, p(H2) = 2.5 kPa) was studied at an ambient pressure of about 100 kPa and a temperature of 1100 degrees C, using deposition arrangements with surface area/reactor volume ratios, [A(S)/V-R], of 10, 20, 40 and 80 cm(-1). Steady-state deposition rates and corresponding compositions of the gas phase as a function of residence were determined. The deposition rates in mol/h increase with increasing [A(S)/V-R] ratio at all investigated residence times up to 1 s. However, surface-related deposition rates in mol/m(2)h decreased. As the same results have been obtained in a preceding study using pure methane at a partial pressure of 10 kPa, it has been confirmed that all the kinetics can be determined by changing the [A(S)/V-R] ratio. (C) 1999 Elsevier Science Ltd. All rights reserved.