Study on the Microwave Absorption Properties of Carbonyl-Iron Powder/Carbon Black Composite Coating

The composite coating composed of carbonyl-iron powder (CIP) and carbon black (CB) with epoxy resin as matrix was prepared, and the thickness of coating was 1.5mm. The electromagnetic properties of CIP and CB were measured and analyzed, respectively. The microwave absorption properties of the composite coatings were investigated, and the effects of the absorbent content on the microwave absorption properties were discussed. The results showed that CIP was a good magnetic absorbent:, and CB possessed excellent dielectric loss. Besides, the increase of carbonyl-iron powder or carbon black content made the absorption bands (reflection loss less than -4dB) move towards the lower frequency range, and the absorption band could be broadened by enhancing carbon black content. For the sample with 25 wt% CIP and 25 wt% CB, the absorption bandwidth achieved 10.1 GHz in 7.9-18 GHz frequency range, which indicated that the excellent microwave absorption properties of the composite coating were shown in the X and Ku bands.