exist on the surface of polymer composite even though it cannot be
confirmed by Fig. 2. Sample 2 shows similar cross section with
Sample 1. The carbon black particles were not shown in cross
section of coated aluminum, however, added carbon black particles
may exist in between the composite and aluminum substrate. Fig. 3
shows cross sectional SEM images of Sample 3. The carbon fibers in
the carbon paper penetrated into the PAI composite and polypropylene
composite to form a mixed structure. The PAI composite
could support the upper layer and some of the carbon fibers in the
PAI composite came in contact with the aluminum substrate. The
diameters of both the carbon fibers embedded in the PP composite
and carbon paper were 7e9 mm. The thicknesses of the composite
mixed with carbon paper and PAI mixed with carbon paper layers
were 100 mm and 35 mm, respectively