Tuning SiC nanowires interphase to improve the mechanical and electromagnetic wave absorption properties of SiCf/SiCnw/Si3N4 composites

• The SiC nanowires (SiC nw ) were prepared and successfully tuned the interphase of the SiC f /SiC nw /Si 3 N 4 composites. • The introduction of SiC nw made the flexural strength of the SiC f /SiC nw /Si 3 N 4 composite improve to 333 ± 29 MPa. • The SiC nw interphase enhanced the dielectric loss of the composite, achieving a RC min of −51.4 dB. The interphase of composites is a vital element in controlling the overall performance. Herein, the SiC nanowires (SiC nw ) were grown on the interface of the SiC fiber (SiC f )/Si 3 N 4 composites and successfully achieved the integration of enhanced mechanical and electromagnetic wave (EMW) absorption performance. The introduction of SiC nw made the bonding between the SiC f and Si 3 N 4 matrix more appropriate, thereby enhancing the mechanical properties. The defects, stacking faults, twin boundaries and heterogeneous interfaces in SiC nw improved the dielectric loss of the composites, which was beneficial to the consumption of EMW energy. Notably, the SiC f /SiC nw /Si 3 N 4 composite containing 1.8 vol% SiC nw demonstrated the optimal mechanical and EMW absorption properties, reaching a flexural strength of 333 ± 29 MPa, a minimum reflection coefficient (RC min ) value of − 51.4 dB with a thickness of 3.2 mm and an effective absorption bandwidth (EAB) of 3.5 GHz with a thickness of 2.8 mm. Besides, the fracture mechanism and EMW absorption mechanism are also discussed. This work provides a potential new way to prepare lightweight, stable, and high-performance EMW absorbing materials for aviation and aerospace.