Interfacial polarization and tunable dielectric properties of coaxial SiC/CFs materials

Abstract To investigate the formation mechanism and influencing factors of interfacial polarization at the interface of materials with different conductivity. Semiconductor SiC and conductor carbon fibers are combined to prepare SiC/CFs coaxial structural materials with varying SiC nanoshell thickness by microwave heating. The results indicate that the electrical resistance of SiC/CFs material increases gradually as the SiC nanoshell thickness increased or materials filling ratio decreased. The dipoles form at the introduced interfaces and the ends of the one-dimensional materials. And the resonance frequency corresponding to the dipoles shifts as the electrical resistance value changes. So, we speculate that the resonance frequency of dipoles has a strong dependence on the electrical resistance of composites materials. Moreover, the SiC/CFs materials also exhibited a better impedance matching and electromagnetic wave absorption performance due to the introduction of SiC nanoshell. The minimum reflection loss of SiC/CFs materials was −31.6 dB at a sample thickness of 1.1 mm, which showed a stronger absorption property than that of CFs (−1.2 dB).