Construction of the SiC nanowires network structure decorated by MoS2 nanoflowers in porous Si3N4 ceramics for electromagnetic wave absorption

SiC nanowires (SiCnw) are widely combined with ceramic matrix for electromagnetic wave (EMW) absorption due to their good conductive network structure. However, the single loss mechanism limits its further application in the field of EMW absorption. Herein, a novel three-dimensional network of SiCnw decorated by MoS2 nanoflowers with a "flower-branched" structure was synthesized in the pores of porous Si3N4 ceramics (MoS2/SiCnw/ Si3N4) by precursor infiltration and pyrolysis combined with hydrothermal reaction. The morphology, pore structure, and dielectric properties of porous MoS2/SiCnw/Si3N4 ceramics were investigated. The interleaved SiCnw within the pore structure provide a large number of growth sites for the MoS2 nanoflowers, ensuring a uniform distribution of MoS2 nanoflowers without agglomeration. Compared with porous SiCnw/Si3N4 ceramics, porous MoS2/SiCnw/Si3N4 ceramics achieve improved microwave absorption performance with an effective absorption bandwidth of 3.50 GHz at a thickness of 2.38 mm and a minimum reflection loss of -70.48 dB at a thickness of 2.10 mm. The excellent EMW absorption performance is attributed to the interfacial polarization loss caused by the MoS2-SiCnw heterogeneous interface, the conduction loss from the SiCnw conductive network, and the defect-induced dipole polarization loss. This work provides new insight into the development of high performance ceramic-based wave absorbing materials.