Polymer-Derived Lightweight SiBCN Ceramic Nanofibers with High Microwave Absorption Performance

Lightweight SiBCN ceramic nanofibers were prepared by a combination of electrostatic spinning and high-temperature annealing techniques, showing tunable electromagnetic wave absorption. By controlling the annealing temperature, the nanoscale architectures and atomic bonding structures of as-prepared nanofibers could be well regulated. The resulting SiBCN nanofibers ∼300 nm in diameter, which were composed of an amorphous matrix, β-SiC, and free carbon nanocrystals, were defect-free after annealing at 1600 °C. SiBCN nanofibers annealed at 1600 °C exhibited good microwave absorption, obtaining a minimum reflection coefficient of -56.9 dB at 10.56 GHz, a sample thickness of 2.6 mm with a maximum effective absorption bandwidth of 3.45 GHz, and a maximum dielectric constant of 0.44. Owing to the optimized A + B + C microstructure, SiBCN ceramic nanofibers with satisfying microwave absorption properties endowed the nanofibers with the potential to be used as lightweight, ultrastrong radar wave absorbers applied in military and the commercial market.