Carbon Nanotube Reinforced Composites: Metal and Ceramic ...

Figure 8.5 Tissue responses of (1) HA/MWNT and (b) ZrO2/HA
composite specimens after implantation into muscle of rats for
three days.Reproduced with permission from [33]. Copyright Ó
(2007) Elsevier.
HA/MWNTnanocomposite exhibits better biocompatibility than ZrO2/HA composite.
The outcome of in vivo experiment for HA/MWNT nanocomposite is similar
to that of SiC/MWNT nanocomposites [9]. More studies are needed in near future
to improve the fabrication process, mechanical property and biocompatibility of
HA/MWNT nanocomposites for biomedical applications.
8.3
Potential Applications of CNT–Metal Nanocomposites
8.3 Potential Applications of CNT–Metal Nanocompositesj223
Conventional metal-matrix composites reinforced with ceramic materials and carbon
fibers found extensive structural applications in aerospace, automotive and transportation
industries. The incorporation of ceramic reinforcements and carbon fibers
into metal matrices increases the tensile strength and stiffness but degrades the
ductility markedly. Toughness is a key factor that influences the performance of
metal-matrix composites for various engineering applications. Carbon fibers produced
from PAN precursor have reached their performance limit. Carbon nanotubes
with superior flexibility can overcome the inherent problems of ceramic fillers and
carbon fibers. Thus, multifunctional composites with improved mechanical, electrical
and thermal properties can be prepared by adding low level content of nanotubes.
Such nanocomposites are considered to be an important new class of structural
materials for the mechanical components of microelectromechanical systems such
as high-frequency micromechanical resonator devices [42]. The main obstacles for
commercialization of CNT-reinforced metals are the high cost of CNTs and agglomeration
of fillers in metal matrices. There will certainly be more effective applications
of light-weight CNT-reinforced metals as structural and functional materials in the
foreseeable future through novel improvement in processing techniques and cost
reduction.