Hierarchically structured composite with 3D interlocking architecture for multi-band defense

The development of high-performance electromagnetic wave absorbing (EMWA) materials for radar stealth applications poses a persistent challenge, particularly when addressing the demanding requirements of diverse frequency bands in increasingly complex and dynamic environments. Precisely tailoring the microstructure of these materials presents a powerful strategy for achieving multifunctional integration and unlocking new possibilities for practical applications. In this work, we present a novel hierarchically structured composite foam with 3D interlocking architecture, fabricated through a straightforward foaming and calcination process. It features a unique dual three-dimensional continuous phase structure that facilitates the formation of an efficient conductive network, promoting free electron mobility and enhancing polarization loss. The composite demonstrates exceptional EMWA performance, exhibiting a wide effective absorption bandwidth (EAB) of 6.1 GHz and a remarkable absorption intensity of −63.2 dB along with RCS reduction value up to 28.7 dB m 2 . Furthermore, the composite illustrated strong infrared stealth properties and efficient photothermal conversion abilities. When heated to 56 °C, its surface temperature only increased by 4 °C in 10 min. Under direct sunlight, its surface temperature rose from 21 °C to 71 °C in just 6 min. Lightweight, flexible, and adaptable to diverse environmental conditions, the HCC composite holds significant promise as a multi-spectrum defense material. Its versatility makes it an ideal candidate for integration into a wide range of equipment, clothing, and wearable technologies , offering advanced capabilities for radar, infrared, and visible light signature reduction. This study presents a novel hierarchically structured composite foam for electromagnetic wave absorption in radar stealth applications, featuring a 3D interlocking architecture that enhances conductivity and polarization loss. It demonstrates an effective reflection loss of −63.2 dB with an absorption bandwidth (EAB) of 6.1 GHz, and achieves a maximum EAB of 8.3 GHz with a peak absorption intensity of −40.6 dB. Additionally, the composite exhibits strong infrared stealth and photothermal properties. Its lightweight and flexible design suggests excellent potential for integration into various equipment and wearable technologies, making it a promising multi-spectrum defense material.