Tuning the microstructure of porous SiCnw/SiC fabricated by vat photopolymerization 3D printing for electromagnetic wave absorption

SiC is recognized as a viable material for electromagnetic wave (EMW) absorption due to its unique physicochemical properties. However, there are still some challenges at present, such as poor EMW absorption performance and difficulty in the fabrication of complicated structures for optimized EMW properties. Here, we presented a novel strategy through vat photopolymerization (VPP) 3D printing technology and carbothermal reduction to prepare porous SiCnw/SiC ceramics with controlled topologies and excellent EMW absorption properties. The gradient hole structure produced by carbothermal reduction facilitates material impedance matching regulation and improves incident wave multiple scattering as well as the in-situ grown SiCnw acts as the dipole center and improves incident wave dielectric loss. Porous SiCnw/SiC ceramics achieve improved EMW absorption performance with a minimum reflection loss (RL) of -57.67 dB at a thickness of 2.20 mm and with an effective absorption bandwidth (EAB) of 3.93 GHz at a thickness of 2.60 mm, covering almost the whole X-band, demonstrating outstanding EMW absorption properties. Furthermore, it exhibits the potential in the application of EMW absorbing devices with complex structure.