To address the bottleneck issue of electromagnetic stealth materials failing in harsh environments such as the marine environment, there is an urgent need to develop high-performance wave-absorbing materials with corrosion resistance. In this study, thin-walled, hollow, porous dodecahedral CoFe-C@SiO₂ particles with Fcc-Co, Hcp-graphitic C, and ultra-thin SiO₂ nanoparticle coatings were constructed via chemical synthesis, ZIF-67 templating, tannic acid etching, and high-temperature sintering. Then the composite coating composed of CoFe-C@SiO₂ particles, PDMS, EP, and PANI was prepared by room-temperature spraying. The effects of different PANI contents (0–15%) on the microstructure, wave absorption, and corrosion resistance of the composite coatings were investigated. The results show that with increasing PANI content, the particles on the coating surface change from small, dispersed particles to large, aggregated particles, accompanied by more surface pores. Compared with the particles alone, weak Fcc-Co phases appear in the coating, together with functional groups from EP, PDMS, PANI, and HDTMS. Coatings with different PANI contents all exhibit good adhesion to the substrate and hydrophobicity. As PANI content increases, the water contact angle of the coating decreases. With the increase of PANI content (0-10%), the corrosion durability of the coatings improves. However, more surface pores and reduced hydrophobicity mean that a high PANI content (15%) is not beneficial for enhancing corrosion durability. Excellent impedance matching and attenuation constant enable the 10% PANI coating to achieve the best overall microwave absorption performance, with a minimum reflection loss of −79.02 dB, an effective absorption bandwidth of 6.8 GHz, and a matching thickness of 2.2 mm. Compared with a perfect electric conductor, the 0-10% PANI coatings exhibit a reduction in RCS. Notably, the 10% PANI coating with corrosion durability can effectively attenuate real radar waves. These findings offer a promising strategy for developing electromagnetic wave-absorbing materials that combine excellent microwave absorption with corrosion resistance.

CoFe-C@SiO2 hollow porous polyhedral particles, polymer composite coatings, microwave absorption performance, corrosion resistance, microstructural tuning