Enhanced high‐temperature dielectric and microwave absorption properties of SiC fiber‐reinforced oxide matrix composites

Because of outstanding performances of the SiC fiber‐reinforced ceramic matrix composites in aircraft/aerospace systems, two silicon carbide fiber‐reinforced oxide matrices (SiC f /oxides) composites have been prepared by a precursor infiltration and sintering method. Results indicate that the flexural strength of the SiC f /Al 2 O 3 –SiO 2 composite reaches 159 MPa, whereas that of the SiC f /Al 2 O 3 composite is only 50 MPa. The high‐temperature microwave absorption properties of the composite are significantly enhanced due to choosing Al 2 O 3 and SiO 2 as the hybrid matrices. Particularly, the minimum reflection loss (RL) value of the SiC f /Al 2 O 3 –SiO 2 composite reaches −37 dB in the temperature of 200 °C at 8.6 GHz, and the effective absorption bandwidth (RL ≤ −5 dB) is 4.2 GHz (8.2–12.4 GHz) below 400 °C. The superior microwave absorption properties at high temperatures indicate that the SiC f /Al 2 O 3 –SiO 2 composite has promising applications in civil and military areas. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47097.