Multiscale Structure Boosting Bi-Functional Intelligent Anti-Corrosionand Microwave Absorption Based on Ferromagnetic Absorber

Abstract

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.

Keywords: Microwave absorption, Intelligent self-healing technology, Carbonyl iron, Multiscale structure, Magnetic-dielectric synergistic mechanism