Achieving C/CuO microfiber composites with efficient microwave absorbing performance at low thickness

Abstract

The carbon fibers with low density still face significant microwave absorbing application issues due to their high dielectric constant. Herein, C/Cu core–shell microfiber composites are prepared by electroless plating. The Cu coating of C/Cu core–shell microfiber composites is oxidized to CuO at 300 °C and 400 °C temperature. The morphology, microstructure, and electromagnetic characteristics of C/CuO microfiber composites were analyzed. The diameter of all the fiber composites was about 7–8 μm. The CuO coating thickness formed at 300 °C and 400 °C temperature is 30–90 nm and 300–900 nm, respectively. The annealing process tunes the electromagnetic characteristics and optimizes impedance matching. The minimum reflection loss (RL) value of C/CuO core–shell microfiber composites annealed at 300 °C temperature remarkably reaches − 46.0 dB at 1.06 mm thickness and 3.6 GHz effective absorption bandwidth (RL ≤ − 10 dB). The C/CuO microfiber composites can be the ideal absorbing materials at a lower thickness.