Embedded SiO₂ interface in SiCnws/Ba_0.75Sr_0.25Al₂Si₂O₈ ceramic with enhanced electromagnetic absorption at elevated temperature

For high-temperature electromagnetic absorption materials, higher polarization loss is needed to balance the impedance mismatch due to greater conduction loss at elevated temperatures. Here, a SiO₂ interface was introduced into a SiCnws/BSAS ceramic based on wide bandgap and low dielectric constant characteristics of SiO₂. The interface structure was tailored by changing the SiO₂ content. When the SiO₂ content reached 15 vol%, three-phase interlaced interfaces were formed, which produced many nano-heterointerfaces that increased the polarization loss by 77.5 %. The optimized SiCnws/SiO₂-BSAS ceramic achieved enhanced electromagnetic absorption from 298 K to 873 K, and its effective absorption bandwidth reached 4.1 GHz at 873 K. The electromagnetic absorption mechanism was analyzed from the perspectives of electron transport and space charges. This heterointerface design strategy provides a new method for the development of high-temperature electromagnetic absorption materials.