In-situ reaction strategy toward Sc₂O₃ reinforced SiOC ceramics for enhanced microwave absorption performance

Modified SiOC ceramic as advanced functional material has drawn great attention due to low density, tailored microstructure and high-temperature oxidation resistance. However, the lower dielectric property hindered microwave absorption (MA) performance. Herein, Sc₂O₃ reinforced SiOC composite ceramics with tailorable composition were successfully prepared by pyrolysis of a Sc (NO₃)₃ modified polysiloxane (PSO) precursor at 1000 °C followed by heat-treatment at 1300 °C. The in-situ growth of Sc₂Si₂O₇ and SiC nanowires from amorphous SiOC ceramic effectively improved dielectric and MA performance. Therefore, as-obtained composite ceramic with 10 wt% Sc achieved the broadest effective absorbing bandwidth (EAB) covering the whole X-band and the minimum reflection coefficient (RC) of −22.37 dB at 10 GHz at 3.1 mm. The excellent MA property is primarily attributed to the balance of conductive loss from SiC nanowires and multiple interfacial polarization loss. This work will contribute to the designing strategy of microwave absorbing ceramics materials and inspire researchers for their future work.