Fabrication of thin and lightweight cobalt-coated quartz fiber/aluminosilicate composites for high-temperature microwave absorption

Abstract

High-temperature microwave-absorbing composites are drawing increasing research attention because of their potential applications in stealth technology. However, materials suited to elevated temperatures are limited. Herein, we propose a high-temperature microwave-absorbing ceramic composite that contains cobalt-coated quartz fiber and an aluminosilicate matrix. The designed composite structure possesses excellent heat resistance and chemical resistance. Furthermore, the added cobalt enhances the dielectric and magnetic loss characteristics of the material, which were measured at X-band (8.2–12.4 GHz) in the range of room temperature (RT) to 1200 °C. The specimen complex permittivity increases with measuring temperature because of the change in dielectric polarization and electrical conductivity values, in accordance with the Debye and Arrhenius theories. The proposed high-temperature microwave-absorbing ceramic composite has an overall thickness of 3.755 mm. It exhibits excellent electromagnetic absorption performance with reflection loss (RL) values are −48.94, −41.76, and −45.05 dB, and bandwidths (RL < −10 dB) are 3.63, 2.24, and 2.81 dB at RT, 600 °C, and 1200 °C, respectively. The optimal impedance matching, strong attenuation, and synergistic effect of dielectric and magnetic losses enhance microwave absorption performance. Hence, the proposed composite has promising applications in high-temperature environments. © 2022 Elsevier Ltd and Techna Group S.r.l.