Preparation and Reaction Kinetics of Carbon Nanotubes/Aluminum Composite Powders Using Polymer Pyrolysis Method

Abstract

The method of polymer pyrolysis chemical vapor deposition (PP-CVD) was used to in situ grow carbon nanotubes (CNTs) on the micro and nano sized flake like aluminum powder substrates. The vapor species were in situ produced by pyrolysis of polyethylene glycol (PEG) including the carbon sources, which was the main difference between the PP-CVD and conventional CVD methods, while the catalyst nanoparticles were pro- duced by the reaction between citric acid (CA) and cobalt nitrate (Co(NO3)2) on aluminum powder surfaces. The reaction mechanism of PP-CVD was studied with the analysis of experiments and reaction kinetics mod- eling, revealing the influence of the vapor species produced by pyrolysis of PEG and CA and surface vapor-solid re- actions on catalyst nanoparticles on CNT growth rates. The CNTs growth rates increases with the increase of reaction temperature and initial partial pressure of CO, which is influenced by the content of PEG and CA, and decreases with the increase of catalyst density and initial partial pressure of H2. The variation trends of the simulated CNTs average length with reaction temperature and time are consistent with the experimental results. Thus, this work provides new theoretical basis to the further optimization of fabricating CNTs/aluminum composite powders.