Dielectric and microwave absorption properties of plasma sprayed short carbon fibers/glass composite coatings

Short carbon fibers (SCFs)/glass composite coatings were fabricated by low power plasma spraying system. The morphology and microstructure of the coatings were observed. The dielectric and microwave absorption properties of the coatings with homogeneously dispersed SCFs were investigated in the frequency range of 8.2-12.4 GHz. The results show that both epsilon' and epsilon aEuro(3) monotonically increased with the increase of SCFs content, which could be ascribed to the enhanced electronic relaxation polarization, interfacial polarization and conductivity. And the Cole-Cole plots indicate that the interfacial polarization plays a dominant role on polarization mechanism with the increase of SCFs content. The effects of SCFs content and thickness on the microwave absorption properties were investigated. The composite coating containing 6.04 wt% SCFs shows that reflection loss below -10 dB (over 90 % microwave absorption) is in the frequency range of 8.9-11.4 GHz and the minimum value was -27.9 dB at 10.1 GHz with the thickness of 2.2 mm. The results indicate that SCFs/glass composite coating could be a potential microwave absorbing material used in 8.2-12.4 GHz.