0D Fe ₃ O ₄ Nanoparticles Anchored on 2D Layered Double Hydroxides: A Composite Structure for Enhanced Microwave Absorption and Corrosion Protection

ABSTRACT To meet the stealth needs of submarines at sea, researchers have developed wave‐absorbing coatings. However, the marine environment tends to corrode the coatings and affect their performance. Therefore, it is necessary to develop materials with both wave‐absorbing and anti‐corrosion functions. In this study, we developed Fe ₃ O ₄ /LDHs composite with enhanced microwave absorption properties by uniformly anchoring Fe ₃ O ₄ particles onto the surface of hexagonal MgAl‐layered double hydroxides (LDHs) through one‐step hydrothermal and hot‐solvent methods. The even dispersion of Fe ₃ O ₄ mitigates nanoparticle agglomeration and promotes synergistic effects between the magnetic and dielectric components, significantly boosting magnetic loss. The composite achieved a minimum reflection loss (RL _min ) of −53.46 dB, nearly double that of pure Fe ₃ O ₄ (−27.31 dB), while maintaining the same effective absorption bandwidth (EAB). Moreover, the Fe ₃ O ₄ /LDHs demonstrate excellent dispersion ability in epoxy (EP). The resistance to corrosion of Fe ₃ O ₄ /LDHs@EP is significantly enhanced, shown by the low‐frequency impedance modulus, which stays above 10 ¹¹ Ω cm ² even after 19 days of immersion, which was four orders of magnitude higher than that of the pure Fe ₃ O ₄ @EP coatings (10 ⁷ Ω cm ² ). The Fe ₃ O ₄ /LDHs composite material exhibits dual capabilities of stealth and anti‐corrosion, providing valuable insights for the development of marine stealth technologies.