The resin-ceramic-based Fe3O4/graphite composites rapidly fabricated by selective laser sintering for integration of structural-bearing and broadband electromagnetic wave absorption

In this paper, the mixed powders of Natural Flake Graphite (NFG), Thermosetting Phenolic resins (PF), Fe3O4, and Mullite ceramic (MC) were prepared by mechanical ball milling. The resin-ceramic-based Fe3O4/NFG (Fe3O4/NFG@MC/PF/EP) composites were fabricated by selective laser sintering (SLS) and vacuum impregnation. The effects of laser power on the mechanical and microwave absorption properties of the composites were investigated. Mechanical tests showed that the change of bending strength after impregnating epoxy resin (EP, E-44) solution was consistent with the change of open porosity. When the laser power was 12 W, the open porosity was 65.23 %, and the ultimate bending strength was 8.03 MPa, nearly 27 times higher than that of the green body. Electromagnetic tests showed that varying the laser power and matching thickness can effectively modulate the microwave absorption properties of the composites. When the laser power was 20 W, and the thickness was 2 mm, the minimum reflection loss of the composites was −41.81 dB, and the effective absorption bandwidth was 6.56 GHz (11.04–17.60 GHz). Therefore, the resin-ceramic-based Fe3O4/NFG composites fabricated by SLS can integrate wave absorption and load bearing. The coordination of absorption and mechanical properties can be achieved by adjusting the laser power, which has a broad application prospect in industrial electromagnetic and microwave absorption fields.