Magnetic metal absorbers exhibit remarkable microwave absorption capacity. However, their practical application is severely limited due to their susceptibility to corrosion, particularly in marine environments. To address this challenge, we propose a novel approach involving the modification and control of FeCo/rGO microwave absorbers using rare earth lanthanum (La). This strategy aims to achieve both high-performance microwave absorption and enhanced resistance to marine corrosion. In this study, we employ a La 2 O 3 modifying control strategy to refine the FeCo magnetic particles and coat them with CoFe 2 O 4 on the surface, leveraging the pinning effect of in situ generated La 2 O 3 . This process enhances the interface polarization of the absorbers, thereby improving their electromagnetic performance and marine corrosion resistance . Consequently, the La 2 O 3 modified FeCo@rGO composites exhibit broadband absorption, covering a wide frequency range of 6.11 GHz at 1.55 mm. Notably, the electromagnetic properties of the La 2 O 3 modified FeCo@rGO absorbers remain stable even after prolonged exposure to a 3.5 wt% NaCl solution, simulating marine conditions, for at least 15 days. Furthermore, we perform first-principle calculations on FeCo and FeCo O to validate the corrosion resistance of the La 2 O 3 modified FeCo@rGO composites at the atomic level. This comprehensive investigation explores the control of rare earth lanthanum modification on the size of magnetic metal particles, enabling efficient electromagnetic wave absorption and marine corrosion resistance. The results of this study provide a novel and facile strategy for the control of microwave absorbers, offering promising prospects for future research and development in this field.
Meng Ma,Wenqin Shao,Qindan Chu,Wenting Tao,Si Chen,Yanqin Shi,Huiwen He,Yulu Zhu,Xu Wang
With the strong support of the government for emerging technology industries, electromagnetic waves have brought convenience to people's lives, but also become an undeniable new source of pollution. Therefore, it is vital to develop new high-performance electromagnetic shielding materials. Herein, we designed a well-structured asymmetrical gradient multilayer composite film by constructing a controllable electromagnetic gradient. Using cellulose nanofibers as the matrix, a layer-by-layer filtration method was used to rationally distribute FeCo@rGO and MXene fillers to build an ordered multilayer structure that provides alternating conductive and magnetic gradients. Owing to gradient absorption shielding and reflection mechanisms for electromagnetic waves within the film layer, the EMI shielding efficiency (EMI SE) of the asymmetrical gradient alternating six-layer composite film reached 45.2 dB (X-band), and the reflection coefficient was reduced to 0.71 when 20 wt% filler was added. In addition, this composite film has good thermal conductivity and mechanical properties, exhibiting thermal conductivity of 2.90 W (m−1 K−1) and tensile strength of 26.2 MPa. This strategy provides a feasible approach for designing electromagnetic shielding composite materials with adjustable electromagnetic properties and has significant practical significance in expanding the application of MXene-based composite materials.
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