Layered composites made of polymer derived SiOC/ZrB₂ reinforced by ZrO₂/SiO₂ fibers with simultaneous microwave absorption and thermal insulation

To simultaneously improve the microwave absorption and thermal insulation properties of the ceramic materials for stealth high-speed vehicles, layered composites made of polymer-derived SiOC/ZrB₂ reinforced by ZrO₂/SiO₂ fibers were reported in this work. The composites possess a continuous multilayer structure, which was fabricated via the precursor impregnation assisted by hot press curing and pyrolysis using the transparent ZrO₂/SiO₂ fibers and polymer-derived SiOC and nano ZrB₂. The layered composites show an effective absorption band (EAB) of 4.2 GHz at a thickness of 2.9 mm and a minimum reflection loss of –59.34 dB. The exceptional electromagnetic (EM) wave attenuation capability is ascribed to the impedance matching as well as massive EM wave loss caused by the multilayers in which the nano ZrB₂ provides interfacial polarization and electrical conduction loss. With a design of the multi-curvature arch structure, a remarkable reduction of radar cross section can be achieved. Besides, the layered composites exhibit good oxidation resistance and thermal insulation when exposed to the dynamic heating environment, demonstrating the potential application in harsh environments used for multifunctional electromagnetic absorbing materials.