In situ growth of one-dimensional carbon-rich SiC nanowires in porous Sc2Si2O7 ceramics with excellent microwave absorption properties

Abstract

For enhancing the absorption ability of dielectric and electromagnetic wave (EMW), C-rich SiC NWs /Sc2Si2O7 ceramics are successfully fabricated through in-situ growth of SiC nanowires (NWs) into porous Sc2Si2O7 ceramics by precursor infiltration and pyrolysis (PIP) at 1400 °C in Ar. SiC NWs are in-situ formed in the pore channels via a vapor-liquid-solid (VLS) mechanism, the relative complex permittivity increases notably with the content of absorber (C-rich SiC NWs), which tune the microstructure and dielectric property of C-rich SiC NWs/Sc2Si2O7 ceramics. Meanwhile, the minimum reflection coefficient (RC) of C-rich SiC NWs/Sc2Si2O7 ceramic decreases from −9.5 dB to − 35.5 dB at 11 GHz with a thickness of 2.75 mm, and the effective absorption bandwidth (EAB) covers the whole X band (8.2–12.4 GHz) when the content of absorber is 24.5 wt%. The results indicate that Sc2Si2O7 ceramics decorated with SiC NWs and nanosized carbon have a superior microwave-absorbing ability, which can be contributed to the Debye relaxation, interfacial polarization and conductivity loss enhanced by in-situ formed SiC NWs and nanosized carbon phases. The C-rich SiC NWs /Sc2Si2O7 ceramics can be a promising microwave absorbing materials within a broad bandwidth.