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

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)/Si₃N₄ 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 Si₃N₄ 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/Si₃N₄ 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.