J. Phys. IV France 11 (2001) Pr3-1013-Pr3-1021
Deposition process of laminar pyrocarbon from propaneJ. Lavenac, F. Langlais, X. Bourrat and R. Naslain
Laboratoire des Composites Thermostructuraux, UMR 5801 du CNRS, SNECMA-CEA-UB1, Université Bordeaux 1, 3 allée de la Boëtie, 33600 Pessac, France
The deposition mechanisms of smooth laminar (SL) and rough laminar (RL) pyrocarbons from propane are found to be very different, as evidenced by (i) gas phase analysis, (ii) nucleation experiments and (iii) analysis of the deposit composition and nanostructure. SL pyrocarbon results mainly from aliphatic species ; its nucleation needs surface reactive sites where chemisorption and hydrogen abstraction occur ; its growth leads to extended but highly distorted graphene layers which can enclose internal nanoporosity. RL pyrocarbon results mainly from polycyclic aromatic hydrocarbons (PAH) ; its nucleation, which does not depend on the substrate, occurs widely by physisorption of PAH ; the corresponding graphene layers are not very extended but parallel to each other and parallel to the anisotropy plane.
© EDP Sciences 2001