Iron deposition on multi‐walled carbon nanotubes by fluidized bed MOCVD for aeronautic applications

The fluidized bed MOCVD process has been studied in order to uniformly deposit iron nanoparticles on the outer surface of multi‐walled carbon nanotubes (MWCNTs) tangled in balls of 388 µm in diameter. Using ferrocene as organometallic precursor at atmospheric pressure, various reactive atmospheres of deposition (under N 2 , air and H 2 ) and an ozone O 3 surface pre‐treatment of MWCNTs were tested. Around 10 g Fe/100 g MWNCTs were deposited during each run. Under N 2 at 650 °C on the raw MWCNTs, nanoparticles formed of Fe and Fe 3 C were deposited which have catalyzed the formation of carbon nanofibers (CNFs). 20 h of ozone (O 3 ) pre‐treatment improved the number and distribution of iron nanoparticles but without increasing the surface coverage of nanotubes. A more intense amorphous carbon deposit also appeared. Under H 2 at 550 °C, the amorphous carbon was partly eliminated but fewer iron nanoparticles were present. Under air at 450 °C, a part of the MWCNTs was lost and a Fe 2 O 3 shell covered each remaining MWCNTs ball. New works are in progress to increase more markedly the surface reactivity of MWCNTs and to deposit pure iron. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)