Preparation of Graphite/Ferrite/Resin‐Based Composite High‐Efficiency Wave‐Absorbing Materials by Selective Laser Sintering

Herein, graphite/Fe 3 O 4 /resin‐based composite absorbers are prepared by selective laser sintering (SLS) and vacuum impregnation of epoxy resin. The effects of different graphite–Fe 3 O 4 powder compositions on the absorbing and mechanical properties of the composites are investigated. The results show that with the increase of Fe 3 O 4 content, the absorption performance of the composites first increases and then decreases, and the absorption peak gradually moves from high frequency (12–18 GHz) to low frequency (2–8 GHz). The bending strength of composites decreases with the increasing of Fe 3 O 4 content. When the mass ratio of graphite–Fe 3 O 4 is 4:3, the wave absorption performance is the best, the minimum reflection loss is −54.8 dB, the effective absorption bandwidth is 2.8 GHz (8.72–11.52 GHz), and the bending strength is 11 MPa, which is 9 times higher than that of SLS plain billets. This is because the increase of the Fe 3 O 4 content in the hybrid powder increases the number of heterogeneous interfaces, but decreases the number of holes inside the composite, which affects the number of microwave reflections inside the material, resulting in different wave absorption and mechanical properties. The graphite/ferrite/resin matrix composites prepared by SLS technology achieve the synergy of lightweight, high strength, and good wave absorption properties.