Carbonyl iron absorbers (CI) face significant challenges in practical applications, such as corrosion, interface bonding failure, detachment, and high maintenance costs. Herein, we have developed intelligent self-healing technology based on proactive/passive mechanisms via in situ synthesis of self-healing factors (polydopamine/benzotriazole, PDA/BTA) and physical barrier layers (SiO₂/1,1,1,3,3,3-hexamethyl disilazane, SiO₂/HMDS) to enhance corrosion resistance, while also being compatible with efficient microwave absorption characteristics. The unique multiscale structure gives full play to the utilization of the roles of each functional layer, including the intelligent self-healing features of PDA/BTA, physical shielding and spatial confinement characteristics of SiO₂/HMDS, and magnetic-dielectric synergistic mechanism resulted from the good impedance matching characteristics, the conduction loss, the interfacial polarization loss and natural resonance. The as-fabricated composites achieved an exceptional minimum reflection loss value of -55.4 dB at 10.7 GHz and the effective absorption band of 7.6 GHz. Moreover, it still exhibits obvious self-healing and corrosion resistance characteristics after 360 hours corrosion treatment, ascribed to the self-healing mechanism of PDA/BTA and the blocking intervention effect of SiO₂/HMDS. This work is considered to pave the way for the synthesis of high-performance magnetic absorbers, especially in enhancing their intelligent self-healing ability in corrosive environments.

Microwave absorption materials are prone to degradation in extremely humid and salty environments, and it is still challenging to develop a dense and firm interface to protect microwave absorbers. Herein, a robust FeSiAl@PUA@SiO₂ (PUA: acrylic polyurethane) gradient hybrid was prepared through plasma-enhanced chemical vapor deposition (PECVD) to achieve efficient microwave absorption and anti-corrosion properties. The organic/inorganic dual coat of PUA/SiO₂ not only facilitated the interface polarization but also effectively reduced the dielectric constant and optimized impedance matching. Owing to the unique hybrid structure, the (PECVD-FeSiAl@PUA)@SiO₂ exhibited highly efficient microwave absorbing performance in frequency bands covering almost the entire Ku-bands (12–18 GHz) with a minimum reflection loss (RL_min) of −47 dB with a matching thickness of 2.3 mm. The organic/inorganic dual protection effectively shields against the corrosive medium, as the corrosion potential and the polarization resistance increased from −0.167 to −0.047 V and 8,064 to 16,273 Ω·cm², respectively. While the corrosion current decreased from 3.04 × 10⁻⁶ to 2.16 × 10⁻⁶ A/cm². Hence, the plasma-enhanced densification of PUA created a strong bridge to integrate FeSiAl and organic/inorganic components acquiring dual-function of efficient microwave absorption and anti-corrosion, which opened a promising platform for potential practical absorbers.

Environmentally-friendly magnetic metallic absorbers with high-performing antioxidant property, thermal stability, and anti-corrosion capability have attracted great attention in real-world applications. A surface modification technology of magnetic metallic absorbers with dense and inert materials has been an effective strategy to solve the aforesaid problem. Herein, fluorine-free core–shell carbonyl iron-organic silicon absorbers (CI@SiO₂/1,1,1,3,3,3-hexamethyl disilazane (HMDS)) were fabricated via a facile one-pot synthesis using tetraethyl orthosilicate (TEOS) and HMDS as the precursor of protective layer (SiO₂/HMDS), and CI@SiO₂/HMDS hybrid reveals its long-term corrosion resistance and excellent microwave absorption performance with a minimum reflection loss value of −44.3 dB and an effective absorption bandwidth of 5.3 GHz at a thin thickness of 2.0 mm after immersion in 5.0 wt.% NaCl acidic solutions for 2,160 h. Meanwhile, CI@SiO₂/HMDS hybrid can still achieve the maximum radar cross-sectional (RCS) reduction values about 16.5 dB·m² at the detection θ of 0°. The exceptional microwave absorption performance and structural stability are largely due to the extraordinary wave-transparent property and shielding ability against corrosive medium of SiO₂/HMDS hydrophobic protective layer with a contact angle of 132.5°. The research paves the way for the large-scale and batch production of high-performance magnetic metallic absorbers and increases their survivability and reliability in the harsh environments.