Structure control and growth mechanism of beaded SiC nanowires with microwave absorption properties

Large-scale SiC nanowires (SiC_nws) were successfully synthesized on graphite substrates by a catalyst-free carbon thermal reduction process using low-cost silicone oil, silica powder, and activated carbon. The control of different nanowire structures was achieved by parameter regulation. An in-depth discussion of their growth mechanisms is provided. Beaded SiC_nws consisting of amorphous SiO₂ beads and SiC strings were synthesized at 1400 °C. The formation of beads is mainly due to the supersaturation of SiO vapor, which leads to the reaction of excess SiO to form SiO₂ at the defects of the SiC_nws. The dielectric parameters of beaded SiC_nws were analyzed, and it was found that the beaded SiC_nws have a maximum effective absorption width of 1.84 GHz and a maximum reflection loss of −16.03 dB. The exploration of the growth mechanism of beaded SiC_nws in this study provides a useful reference for the preparation of one-dimensional nanomaterials.