Preparation of SiC/SiO ₂ Fibers by Microwave Heating

High energy consumption and complex processes constrain the industrial production of high-performance SiC/SiO₂ fibers. A direct synthesis route for SiC/SiO₂ fibers at low temperatures (700-1100 °C) is developed in this work using pure-material microwave heating without external heating assistance. The phase composition, microstructure, and microwave-assisted synthesis process of the fibers were systematically investigated. A two-stage growth mechanism is proposed based on real-time microwave coupling analysis, consisting of kinetically controlled SiC fiber growth followed by thermodynamically driven SiO₂ bead formation. The SiC/SiO₂ fibers synthesized at 1000 °C exhibit outstanding electromagnetic wave absorption performance, achieving a minimum reflection loss (<i>RL</i> _min) of -42.49 dB at an ultrathin thickness of 2.9 mm, demonstrating great potential for lightweight, high-efficiency microwave absorbers.