Zirconium carbide modified SiOC composites with porous lamellar structures for broadband microwave absorption and thermal stability

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The inherent dielectric properties and thermal stability of transition metal carbides (TMCs) have generated significant interest because of their potential use in electromagnetic (EM) wave applications at various temperatures. However, the high relative complex permittivity and conductivity of TMCs can cause impedance mismatch issues when utilized as absorbers, thereby limiting their effectiveness in absorbing EM waves. To solve these problems, ZrC/ZrO2–SiOC composites with a porous lamellar structure were prepared using polymer-derived ceramics (PDC) technology, which involved dispersing zirconium carbide (ZrC) into modified polysiloxane (PSO). The resulting ZrC/ZrO2–SiOC composite (with 5 wt% ZrC content sintered at 900 °C) achieved remarkable EM wave absorption performance, with a minimum reflection loss (RLmin) of −33.52 dB at 13.0 GHz and an effective absorption bandwidth (EAB) extending up to 7.75 GHz. This exceptional absorption of EM waves is due to the synergistic interplay of various factors such as interface polarization, dipole polarization, and conduction loss. Moreover, the composites exhibit a minimal weight loss of less than 2 % when exposed to air at temperatures ranging from 25 to 1200 °C. This study not only broadens the application possibilities of TMC materials in microwave absorption but also highlights their potential for further improvement and deployment in high-temperature environments.