One-step synthesis of SiC/C nanocomposites by atmospheric thermal plasmas for efficient microwave absorption

The simple preparation of SiC/C nanocomposites for efficient microwave absorption is a significant and challenging issue. In this work, an atmospheric thermal plasma was used to achieve the one-step, continuous, and controllable synthesis of SiC/C nanocomposites via hexamethyldisilane decomposition. The microstructure, phase composition, elemental composition, and microwave absorption performance of the SiC/C nanocomposites were investigated. The results indicated that the as-prepared SiC/C nanocomposites were a mixture of C-coated beta-SiC nanoparticles with an average size of 11-16 nm and free carbon layers with the layer number of 1-6. The ratio of SiC to carbon layers could be tuned by adjusting the arc current, hydrogen/carbon contents. It was also found that the SiC/C nanocomposites with high carbon content exhibited good microwave absorption, and the optimal reflection loss approached-60.6 dB at 7.39 GHz. The microwave absorption mechanism indicated that the presence of carbon layers in the SiC/C nanocomposites improved the polarization and conduction loss, which was closely associated with the enhanced microwave absorption. These results afford a novel strategy for designing and synthesizing SiC/C nanocomposites with strong microwave absorption.

Automated summary

The one-step, continuous, and controllable synthesis of SiC/C nanocomposites was achieved using atmospheric thermal plasma. The microwave absorption performance of the nanocomposites was improved by adjusting the carbon content. These results provide a new strategy for designing and synthesizing SiC/C nanocomposites with strong microwave absorption.