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 asprepared nanofibers could be well regulated. The resulting SiBCN nanofibers similar to 300 nm in diameter, which were composed of an amorphous matrix, beta-SiC, and free carbon nanocrystals, were defect-free after annealing at 1600 degrees C. SiBCN nanofibers annealed at 1600 degrees 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.