Multiphase ceramic SiBCN-ZrO₂/ZrC/ZrB₂/SiC with ultra-wide bandwidth electromagnetic absorption

Broadband electromagnetic (EM) absorption is challenging for non-magnetic monolithic materials without any macro-structural design, primarily due to the impedance mismatch and insufficient EM dissipation. This study reports a multiphase ceramic made of SiBCN-ZrO₂/ZrC/ZrB₂/SiC, with an ultra-wide bandwidth EM absorption capability. The composites were prepared using a polymer-derived ceramic (PDC) method. The multiphase EM absorbers (ZrO₂/ZrC/ZrB₂/SiC) synergistically tune the dielectric properties and impedance matching of the composite ceramics, allowing the cross-band EM absorption at a low thickness. The SiBCN-ZrO₂/ZrC/ZrB₂/SiC composite ceramics pyrolyzed at 1400 °C for 2 h has an effective absorption bandwidth (EAB) of 11.06 GHz at a thickness of only 2.4 mm, covering parts of the C-band, the entire X-band and Ku-band (6.94–18.00 GHz). This research proposes a strategy for producing a monolithic composite ceramic with broadband EM absorption, which can also be used in high-temperature harsh environments.