Qt. Le et al., Fe(NO3)(3 center dot)9H(2)O and Fe-3(CO)(12) as catalyst precursors for the elaboration of VGCF: SEM and TEM study - improvement of the process, CARBON, 37(3), 1999, pp. 505-514
Using Grafoil(R) (Union Carbide) as a substrate, we compare the effect of t
wo catalyst precursors, namely Fe(NO3)(3).9H(2)O and Fe-3(CO)(12) on the el
aboration of carbon fibres. For each precursor, the mass of deposited carbo
n, of carbon fibres, and especially the fibre length was found to be strong
ly dependent on the concentration of catalyst precursor over the support. M
oreover the methane percentage in the gas mixture plays an important role i
n the mass of gathered fibres. To observe the modification of the substrate
morphology with increasing temperature, several experiments were interrupt
ed at different temperatures within the 900-1110 degrees C range. The resul
ts obtained from SEM and TEM revealed that at least two kinds of filaments
had grown on the substrate, and that only one of them could give rise to ca
rbon fibres. Precursor filaments were evidenced as having a nanotubular str
ucture and were sometimes agglomerated in bundles. The different stages of
fibre growth are also discussed. (C) 1999 Elsevier Science Ltd. All rights
reserved.