a 26% and 78% lower ICR than Sample 1 because the interfacial
layers provided a conducting path between the composite and
aluminum substrate. Sample 3 had a significantly lower ICR value,
close to that of bare aluminum, due to the effect of carbon fibers in
the carbon paper. The penetrated carbon fibers connecting the
upper carbon particles in the composite to the aluminum substrate
would provide a much better electrical conduction beyond the
polymer-rich phase on the surface of composite as shown in Fig. 5.
Also, ICR of Sample 2 which have relatively higher ICR than Sample
3 tell us that even if conductive materials are added in polymer-rich
region, the effective connection with upper composite layer is
necessary in order to obtain much lower ICR. The agglomeration of
particle and low adhesion with substrate may be reasons of higher
ICR than Sample 3.