Composite Materials Research Progress

146
SEM Analysis
Yuanxin Zhou, Hassan Mahfuz, Vijaya Rangari et al.
SEM analysis was carried out on JSV 5800 JOEL Scanning Electron Microscope. Specimen
from failed samples of flexure tests were selected, prepared and attached to the sample holder
with a silver paint and coated with gold to avoid charge build-up by the electron. Figures 18
and 19 show the SEM micrographs obtained. It is observed from Figures 18a-18b that most of
the damage was located in the loading zone, including large intra and inter-layer delamination
cracks as well as fiber/bundle failures. The damage and the fracture processes were mainly
due to local shear components. They also show interfiber micro-cracks and delamination
cracks. These micrographs also reveal that the carbon fibers were highly oriented with
uniform resin distribution. Figure 19b shows the SEM micrograph in which SiC nanoparticles
(white dots) are distributed uniformly without agglomeration. Also revealing the size of the
filament to be 8-10 microns in diameter and SiC nanoparticle to be of about 30-40 nm range.
(a) (b)
Figure 18. SEM of failed flexure samples in thickness direction.
(a) (b)
Figure 19. SEM of failed flexure samples.