Epoxy (EP) was filled with nano-carbon black(CB) and micron SiC. The effects of CB and SiC fraction on the absorbing
properties of the EP composites were studied. The structure and morphology of the samples were characterized by
scanning electron microscopy (SEM). The spectroanalysis indicates that the absorbent particles are dispersed uniformly
in the coating. At 8 ~ 18GHz, for composite coating with 1.05mm thickness, the absorbing bandwidth less than -5dB is
7.7GHz and less than -8dB is 4.6GHz, and the most reflection loss can reach -19.27dB. With the increase thickness of
the coating, the absorbing peak value moves to the lower frequency. The bandwidth and the wave absorbing peak values
increase along with the increasing of the content of CB filling fraction. And the absorbing mechanism of the composite
was also discussed.