Optimization and mechanistic insights into electromagnetic shielding performance of nano-carbon composite films fabricated via magnetron sputtering

To address the engineering challenges of traditional metal-based electromagnetic shielding materials, including high density, low processing flexibility (elongation <5%), and poor corrosion resistance (failure within ≤72 h in salt spray tests), this study developed a magnetron sputtering-based fabrication system for nanocarbon composites. By optimizing sputtering parameters (power: 300-600 W, substrate temperature: 200-400°C, duration: 30-90 min), copper-aluminum bimetallic nanoparticles (50-200 nm diameter) were controllably deposited on carbon fiber (7-10 μm diameter), carbon nanotubes (20-50 nm diameter), and graphene (≤5 layers), forming a gradient impedance "conductive core-dielectric shell" bilayer structure. Key findings include: (1) Optimized carbon fibers exhibited a 37.73% enhancement in shielding effectiveness (SE) with broadband response (SE ≥30 dB) across the X-band (8-12 GHz); (2) After 150 min sputtering, composite films achieved optimized surface impedance matching (Z: 0.8-1.8), reduced reflection coefficient (R ≤0.5), and increased absorption loss contribution (61.2±3.5%); (3) Finite element simulations demonstrated that the graded interface concentrates electromagnetic energy density in surface pores (50-150 μm diameter), extending attenuation time by 0.82 ns through secondary reflection paths while achieving localized power loss density of 3.7×10? W/m². This work provides a novel fabrication strategy for lightweight, flexible, and environmentally stable electromagnetic shielding materials.

Dr. Huixue Ren is currently a Professor at Shandong Jianzhu University, having obtained his Ph.D. from Nanjing Tech University. He serves as a Senior Member of the Chinese Chemical Society, Deputy Director of the Shandong Environmental Chemistry and Engineering Committee, and was a Visiting Scholar at the Pennsylvania State University, USA. His research focuses on green and low-carbon chemistry, along with the development and application of environmentally functional materials.