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

Abstract

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 β-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.