Carbon Nanotube Reinforced Composites: Metal and Ceramic ...

Figure 2.29 SEM micrographs of (a) CoO nanocrystals and (b)
CoO/MWNT nanopowders containing 7 vol.% MWNT; (c) highresolution
TEM image of the area near the MWNT-CoO interface;
(d) X-ray diffraction pattern of the CoO/MWNT nanopowders.
Reproduced with permission from [110]. Copyright Ó (2007)
Wiley-VCH Verlag GmbH.
due to the absence of oxygen transient bonding layer. As mentioned above, residual
oxygen is found at the nanotube-matrix interface by using funtionalized nanotubes
as precursor materials. Residual oxygen enhances interfacial bonding and mechanical
strength of the composites, but degrades their electrical and thermal properties.
This is because interfacial oxygen bonding layers act as a scattering center for
electron and phonon.
2.8.3
Fe-Based Nanocomposites
2.8 Transition Metal-Based Nanocompositesj77
All the fabrication techniques for making metal–CNT nanocomposites described
above can be referred to as ex situ since the CNTs have been synthesized
independently and then introduced directly into metal matrices of composites
during processing. On the other hand, in situ CNT reinforcement can be synthesized
in situ in the metal matrix using transition metal catalysts through the CO