Preparation and enhancement microwave absorption properties of carbon fibers coated with CoNi alloy by solvothermal

Recently, cobalt-nickel nanoparticles with ferromagnetic properties are often used in wave absorption materials and sensors. In this paper, after surface treatment of carbon fiber, a simple solvothermal method was used to grow cobalt-nickel alloy particles on the surface of carbon fiber, which was expressed as CoNi alloy/carbon fibers composite. The surface treatment process of carbon fiber, the structures, morphology, chemical, and electromagnetic parameters of CoNi alloy/CFs composites were analyzed in detail. In the composite material, more loss mechanisms are introduced to balance impedance matching, thus achieving designable electromagnetic parameters, ultra-thin thickness, low density, wide absorption frequency band, and strong electromagnetic absorption capacity. The effects of permittivity and permeability on the absorbing properties of the composites were compared under different CoNi alloy content (15–45%). The absorption frequency of composites moves to high-frequency and shows better performance, with the minimum RL of − 55.4 dB at 17.1 GHz and the effective absorption bandwidth is 4.1 GHz (thickness 1.2 mm). Accordingly, as-prepared CoNi alloy/CFs composites could be used as electromagnetic wave absorbing materials with great application prospects.