Effect of SiC interphase on the mechanical, high-temperature dielectric and high-temperature microwave absorption properties of the SiCf/SiC/Mu composites

In this study, SiC interphase was prepared via a precursor infiltration-pyrolysis process, and effects of dipping concentrations on the mechanical, high-temperature dielectric and microwave absorption properties of the SiCf/ SiC/Mu composites had been investigated. Results indicated that different dipping concentrations influenced ultimate interfacial morphology. The SiC interphase prepared with 5 wt% PCS/xylene solution was smooth and homogeneous, and no bridging between the fiber monofilament could be observed. At the same time, SiC interphase prepared with 5 wt% PCS/xylene solution had significantly improved mechanical properties of the composite. In particular, the flexural strength of the composite prepared with 5 wt% PCS/xylene solution reached 281 MPa. Both epsilon' and epsilon '' of the SiCf/SiC/Mu composites were enhanced after preparing SiC interphase at room temperature. The SiCf/SiC/Mu composite prepared with 5 wt% PCS/xylene solution showed the maximum dielectric loss value of 0.38 at 10 GHz. Under the dual action of polarization mechanism and conductance loss, both epsilon' and epsilon '' of the SiCf/SiC/Mu composites enhanced as the temperature increased. At 700 degrees C, the corresponding bandwidth (RL < -5 dB) of SiCf/SiC/Mu composites prepared with 5 wt% PCS/xylene solution can reach 3.3 GHz at 2.6 mm. The SiCf/SiC/Mu composite with SiC interphase prepared with 5 wt% PCS/xylene solution is expected to be an excellent structural-functional material.

Automated summary

In this study, SiC interphase was prepared using a precursor infiltration-pyrolysis process. The effects of dipping concentrations on the mechanical, high-temperature dielectric, and microwave absorption properties of SiCf/SiC/Mu composites were investigated. It was found that the SiC interphase prepared with 5 wt% PCS/xylene solution had a smooth and homogeneous morphology and greatly improved the mechanical properties of the composite. The SiCf/SiC/Mu composites also showed enhanced dielectric properties and microwave absorption at high temperatures.