Carbon Fiber Reinforced PA6 Composites With Aramid Nanofiber‐Encapsulated Magnetic Interfaces for Synergistic Enhancement of Mechanical and Microwave Absorption Properties

To enhance the electromagnetic stealth functionality of carbon fiber (CF)‐based thermoplastic composites, surface modification serves as a commonly employed approach. However, maintaining the structural integrity of modified layers under harsh processing conditions remains challenging, often compromising the functional reliability of the final composites. This work presents a heterogeneous architecture in which NiCo alloy nanoparticles are encapsulated within aramid nanofilm (ANF) and firmly attached to the CF surface. This configuration improves the interfacial adhesion between CF and polyamide 6 (PA6), while also counteracting the mechanical weakening caused by fiber damage during high‐temperature reduction. Furthermore, this architecture enhances the composite's impedance matching and electromagnetic wave attenuation capacity. The resultant ANF@NiCo‐CF/PA6 material demonstrated outstanding microwave absorption characteristics, attaining a minimum reflection loss of −60.73 dB and an effective absorption bandwidth of 4.9 GHz at only 1.5 mm in thickness. This modification strategy demonstrates excellent structural stability under composite processing conditions, offering a novel pathway for developing CF‐reinforced thermoplastic stealth composites with superior interfacial and functional properties.