Influence of surface on chemical kinetic of pyrocarbon deposition obtained by propane pyrolysis

Pyrolytic carbon deposition was realized on carbon fibers by the pyrolysis of propane at low pressure (2.7 kPa) and at a temperature of 1273 K, as a function of the variation of the ratio surface of carbon fibers/reactor volume (A/V). The deposition rate and the composition of other products of pyrolysis were studied. The deposition rate decreases when A/V increases, and does not seem to depend on the time of infiltration (for low duration), whereas the depositioned quantity of carbon increases. The interactions existing between the gas phase and the deposition surface should be taken into account; in fact, the quantity of active sites on which the deposition grows should be dependent on the concentration of the radicals of the gas phase.