Power loss density fluctuation of lightweight flexible electromagnetic wave absorption composites constructed by Co-based aerogels with magnetic variation

Higher electromagnetic wave absorption (EMWA) performance, more flexible and lower density are the incompatibility for the flexible EMWA materials, the insufficient analysis of attenuation conditions for every part in the bulk EMWA materials based on electrical/magnetic properties and reflection loss (RL) resulted in the inability to obtain the actual electromagnetic wave (EMW) consumption capacity in EMWA materials during practical applications. In this study, the lightweight flexible EMWA composites fabricated by Co-based aerogels have broadest effective absorption band (EAB, frequency for reflection loss≤−10 dB) of 5.77 GHz, best minimum reflection loss (RL_min) of −49.94 dB and maximum radar cross section (RCS) reduction of 29.55 dB·m². After the salt spray test for the flexible EMWA composites, the largest EAB, optimum RL_min and greatest RCS reduction are 5.42 GHz, −24.41 dB and 19.34 dB·m². The power loss density (PLD) distribution of EMW in all regions of the bulk EMWA materials is calculated based on electromagnetic parameters, and the influence of RL and the magnetic variation on PLD distribution is investigated. The flexible EMWA composite with 18% (in mass) Co-800 aerogel is a very promising lightweight EMWA material for preventing electromagnetic interference/pollution and enhancing radar stealth in the salt-spray environment.