Synthesis of SiC–SiO ₂ nanocomposites using a simple mechanical milling and their microwave absorption performance

Abstract The combination of silicon carbide (SiC) and silicon dioxide (SiO 2 ) holds significant potential for advancing modern technologies, particularly the development of microwave‐absorbing materials (MAMs) due to their unique dielectric properties. In this study, a simple and cost‐effective method has been used to synthesize SiC–SiO 2 nanocomposites from silicon and graphite powders using high‐energy milling at room temperature in air atmosphere, without any heat treatment. X‐ray diffraction, Fourier‐transform infrared spectroscopy, scanning electron microscopy with energy‐dispersive X‐ray spectroscopy, and high‐magnification transmission electron microscopy characterizations confirmed the formation of pure SiC–SiO 2 nanocomposites after milling for 20 h, with particle sizes reduced to sub‐100 nm. Vector network analyzer measurement revealed the composites’ enhancement in microwave absorption performance at a thickness of only 1.50 mm from a minimum reflection loss (RL) of ‒4.00 dB at 10.88 GHz (∼60% absorption) before milling to ‒12.15 dB at 11.50 GHz (∼93% absorption) after 20 h of milling, with further improvement to ‒13.80 dB at 11.50 GHz (∼96% absorption) after 40 h. The effective absorption bandwidth is also enhanced from 0.84 to 1.54 GHz after 20 and 40 h of milling, respectively. The enhanced microwave absorption is attributed to the nano‐size effect, interfacial polarization, and multiple internal reflection. These findings may pave the way for realizing the industrial‐scale production of SiC‐based MAMs.