In situ growth of the Y3Si2C2 interphase in SiCf-reinforced mullite ceramics for enhanced electromagnetic wave absorption

To meet the rigorous demands placed on electromagnetic (EM) wave absorbing (EWA) materials by harsh service conditions and to reduce EM wave power density, the development of ceramic-based EWA materials with high reliability and stability has become a subject of significant focus. In this study, yttrium silicide carbide interphase was in situ synthesized on silicon carbide fibers to fabricate Y₃Si₂C₂–SiC_f composite fibers by the molten salt method. These fibers were then incorporated into a mullite ceramic matrix, and Y₃Si₂C₂–SiC_f/mullite composites were prepared by gel injection molding, aiming at enhancing the EWA properties. The Y₃Si₂C₂–SiC_f/mullite composite exhibited a reflection loss of −28.97 dB at 2.44 mm thickness and an effective absorption bandwidth of 3.066 GHz, outperforming pure mullite and SiC_f/mullite composites due to the addition of Y₃Si₂C₂–SiC_f. A modified Drude–Lorentz model was developed to capture the multi-peak permittivity behavior of Y₃Si₂C₂–SiC_f/mullite composites. The results showed that dipole relaxation and hopping migration of localized electrons played key roles in the overall microwave energy attenuation, which closely matched the experimental data. Furthermore, simulations of the electric field distribution and radar cross-section confirmed the superior energy loss capability and practical application potential of Y₃Si₂C₂–SiC_f/mullite composites. This study offers valuable theoretical insights into the design and application of SiC_f-reinforced ceramic-based EWA materials.