Lattice composites with embedded short carbon fiber/Fe3O4/epoxy hollow spheres for structural performance and microwave absorption

Lightweight absorption materials with superior mechanical properties have received significant attention owing to their potential for use in military stealth and electromagnetic protection applications. Herein, a novel electromagnetic (EM) wave absorbing lattice structured composite material containing a hollow short carbon fiber (SCF)/Fe3O4/epoxy sphere filler, and an epoxy resin matrix, is described. The morphology, density, and isostatic compression strength of the hollow SCF/Fe3O4/epoxy spheres were measured, and the mechanical and electromagnetic wave absorption properties of the epoxy resin composite embedded with the hollow SCF/Fe3O4/epoxy spheres were studied. The results indicate that the composite possessed a high compression strength of ~57.3 MPa with a density of only ~0.92 g/cm3. Furthermore, the effective absorption bandwidth within the range of 2–18 GHz of the composite was 1.8 GHz, with an ultra-thin equivalent thickness of only ~0.48 mm. The macro-sized hollow structure spheres were effective EM wave absorption enhancements, and the lattice composite embedded with these hollow spheres presented a unique structure and excellent absorption performance.