3D printed composites achieve broadband electromagnetic wave absorption by introducing carbon black/carbonyl iron powder porous hollow microspheres

In this paper, carbon black (CB) and carbonyl iron powder (CIP) were successfully combined by solvent evaporation method to prepare CB-CIP porous hollow microspheres and used as reinforcement to prepare electromagnetic wave absorbing composites by 3D printing method. The effects of CB addition on the structure of the composite microspheres and the wave absorption performance were investigated. It is shown that the surfaces of hollow microspheres have many heterogeneous interfaces and pore defects, which can significantly enhance the polarization loss capability. The CB and CIP particles on the surfaces of hollow microspheres are intertwined, which makes the magnetic loss and dielectric loss form a synergistic absorption effect and enhance the microwave absorption capacity of the composite. The maximum reflection loss of sample CB/PLA-3 reaches –47.34 dB at a thickness of 2.5 mm, and the EAB is 4.56 GHz. The EAB reaches a maximum of 5.20 GHz at a thickness of 2 mm. The RCS simulation results of CB/PLA-3 at 11 GHz show that most of the RCS values of the samples are below −20 dBm2 in the range of –90° < Theta < 90°, indicating that the CB/PLA-3 samples has the capability of wide-angle microwave absorption. This paper provides an effective method for the design and preparation of broadband efficient absorbing materials.