Dielectric properties of the SiC fiber-reinforced SiC matrix composites with the CVD SiC interphases

In this study, the SiC coating was deposited on the KD SiC fiber by CVD (chemical vapour deposition) process. The characteristics of the CVD SiC coating were evaluated by SEM, EDS and XRD analysis. Effects of the CVD SiC interphases on the porosity and dielectric properties of the SiC fiber-reinforced SiC matrix (SiCf/SiC) composites, fabricated by precursor infiltration and pyrolysis (PIP) process, were investigated. The results show that the permittivity of the SiCf/SiC composites with the CVD SiC interphases is very large at X-band, which is owing to the existence of the carbon-rich layers in the CVD SiC interphases. Finally, the microwave absorbing properties of the SiCf/SiC composites were simulated.