Blended and layered configurations: tuning high and low frequency broadband absorption in Magnetic-Electro coupling composite foams consisting with carbonyl iron flaky and carbon nanotube

Magnetic-electro coupling composites are highly effective for electromagnetic wave absorption. However, the specific impact of different configurations on their absorption characteristics and mechanisms, particularly in the X-band, remains unclear. In this study, composite foams combining Carbonyl iron flakes (CIF) and Carbon nanotubes (CNT) within a Polystyrene (PS) matrix were constructed by one-step physical constraint foaming technology. Two distinct configurations were designed: blended (CIF/CNT) and layered (CIF-CNT). The content of CIF and CNT was remained at 50 wt.% and 6 wt.%, respectively, with a constant thickness of 2.0 mm. The blended CIF/CNT foam demonstrates a superior effective absorption bandwidth of 3.22 GHz in the relatively high-frequency region, surpassing the 2.72 GHz achieved by the layered CIF-CNT foam. Conversely, the layered CIF-CNT foam exhibits a stronger absorption intensity in the relatively low-frequency region, achieving a with a minimum reflection loss of -33.08 dB compared to -20.14 dB for the blended foam. Mechanism analysis reveals that the blended configuration optimizes impedance matching, whereas the layered configuration enhances interfacial polarization. Consequently, this work provides a significant reference to design magnetic-electro coupling composites to meet requirements of frequency selection absorption characteristics.