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

Abstract

The interphase of composites is a vital element in controlling the overall performance. Herein, the SiC nanowires (SiCnw) were grown on the interface of the SiC fiber (SiCf)/Si3N4 composites and successfully achieved the integration of enhanced mechanical and electromagnetic wave (EMW) absorption performance. The introduction of SiCnw made the bonding between the SiCf and Si3N4 matrix more appropriate, thereby enhancing the mechanical properties. The defects, stacking faults, twin boundaries and heterogeneous interfaces in SiCnw improved the dielectric loss of the composites, which was beneficial to the consumption of EMW energy. Notably, the SiCf/SiCnw/Si3N4 composite containing 1.8 vol% SiCnw demonstrated the optimal mechanical and EMW absorption properties, reaching a flexural strength of 333 ± 29 MPa, a minimum reflection coefficient (RCmin) 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.