Construction of periodic hollow SiC microtube ceramic for synergistic broadband absorption performance at elevated temperatures

Silicon carbide (SiC) has been utilized as a semiconductor material and has been shaped into various structural forms to obtain outstanding electromagnetic wave (EMW) absorption properties, characterized by low weight and excellent absorption capabilities even at high temperatures. A chemical vapor infiltration (CVI) approach was used to synthesis a periodic structured SiC microtube ceramic on a carbon fiber plain preform, taking inspiration from the porous structure found in SiC materials. Afterwards, the carbon fibers were removed by oxidation at a temperature of 900 °C. The periodic structural SiC microtube ceramic exhibited a porosity above 68 %, rendering it a lightweight material possessing a density of 0.8 g/cm³. The SiC microtube ceramic displays a periodic structure and exhibits anisotropy at 0° and 45°, respectively, as a result of the braided structure of the fiber fabric. When evaluated at a 0° angle of incidence, the SiC microtube ceramic, with a thickness ranging from 2.4 to 2.6 mm, showed excellent absorption of EMW energy in the Ku-band frequency range, attenuating more than 90 % of the energy, with a minimum reflection loss of −56.36 dB at 15.65 GHz. SiC microtube ceramics have demonstrated an effective absorption bandwidth exceeding 8.2 GHz throughout a temperature range of ambient temperature to 600 °C, with a thickness of 2.8 mm. Furthermore, the SiC microtube ceramic exhibited stable EMW absorption properties and thermal conductivity even at temperatures as high as 600 °C.