Influence of silicon carbide fiber (SiCf) type on the electromagnetic microwave absorbing properties of SiCf/epoxy composites

A comparative investigation of microstructure, mechanical properties, complex permittivity and microwave absorbing properties of two types of SiCf/epoxy composites were investigated. The microstructure of SiCf was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectra techniques. The different microstructure led to different complex permittivity of the composites. The complex permittivity of KD-ISiCf/epoxy composite was larger than their counterparts of SLF-SiCf/epoxy composite while the flexural strength was almost same. The strong interfacial polarization and high electrical conductivity are attributed to the higher complex permittivity of KD-ISiCf/epoxy composite. Though the complex permittivity of KD-ISiCf and SLF-SiCf composites have big difference, the absorbing properties in the X band (8.2-12.4 GHz) were not good due to the impedance degree and attenuation characteristics cannot meet the requirement at the same time.