The influence of growth temperature on evolution of carbon nanotubes decorated with Fe nanoparticles on diamond/cemented carbide substrate

• MWCNTs/Fe-NPs/diamond/cemented carbide is prepared at the different temperatures.
• The growth of MWCNTs is accompanied by the formation of Fe-NPs.
• The growth of the MWCNT/Fe-NP composites conforms to the concepts of the VLS model.
• The results suggest that the diffusion of carbon atoms in Fe catalysis is bulk diffusion.

Multiple wall carbon nanotubes (MWCNTs) decorated with Fe nanoparticles (Fe-NPs) have been produced on diamond film on cemented carbide substrate (MWCNTs/Fe-NPs/diamond/cemented carbide) by the pyrolysis of FePC at 850 °C, 880 °C and 940 °C, respectively. During the growth process, the growth of MWCNTs is accompanied by the formation of Fe-NPs encapsuled by layers of graphitic carbon. With the increasing temperatures, the structural defects of MWCNTs are improved enormously and the evolution of the MWCNT/Fe-NP/diamond/cemented carbide film morphology is ascribed to the steric hindrance between nanotubes. The diffusion of carbon atoms (vapor) in Fe catalysis (liquid) is bulk (volumetric) diffusion in the synthesis of MWCNT/Fe-NP/diamond/cemented carbide substrate, which is testified on the analysis of the sample grown at the temperature of 940 °C. The growth of the MWCNTs/Fe-NPs/is well explained using the concepts of the vapor–liquid–solid (VLS) model.