Biomedical Engineering Reference
In-Depth Information
4.11
Clustering of carbon nanotubes (CNTs) in a silicon nitride matrix
(Si
3
N
4
-3vol% CNT) (Hvizdo ˇ
et al
., 2011).
4.12 Clusters and porosity connected to SiC nanoparticles in Al
2
O
3
-SiC
nanocomposite.
reduce the strength but their toughening potential is not fully realised, thus
the materials containing them do not exhibit a significant improvement in
fracture toughness (Bala´ zsi et al., 2006; Hvizdosˇ et al., 2011).
In nanocomposites with nanoparticles, the microstructures typically
consist of fine grains because the secondary-phase particles are introduced
in order to hinder the grain growth. Macropores are seldom present in such
materials. However, residual pores at grain boundaries and triple-point
junctions (Fig. 4.12), and/or secondary particle clusters such as those
reported by Csehova´ et al. (2011) are typical defects.
