Society demands effective electromagnetic wave (EMW) absorbers that are lightweight, with a broad absorption band and strong absorption, to solve excessive electromagnetic radiation. Herein, ultralight magnetic graphite-like C₃N₄/carbon foam (MCMF) was fabricated via impregnating polymerized melamine formaldehyde (MF) foams in Fe₃O₄ nanoparticle solution, followed by in situ pyrolysis at 1000 °C. MCMF possesses porous architectures consisting of graphitic C₃N₄/carbon and CFe_15.1. The magnetic particles (α-Fe, Fe₃O₄ and Fe₃C) were formed and modified on the internal skeleton surface. The EMW absorption capacity of MCMF is better than the that of carbonized MF foam without Fe₃O₄ (CMF), possessing excellent absorption behavior, with a minimum RL value of −47.38 dB and a matching thickness as thin as 3.90 mm. The corresponding effective absorbing bandwidth is as broad as 13.32 GHz. Maxwell–Wagner–Sillars (MWS) polarization and the residual loss are proved to be beneficial for such superior absorption behavior. Besides, graphitic C₃N₄ enriches the interface polarization effect and the electromagnetic matching effect. The microporous structures are beneficial for increasing EMW propagation, resulting in internal multiple reflections and scatterings, which are also beneficial for EMW attenuation.

中文翻译：

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具有电磁波吸收特性的超轻多孔三聚氰胺-甲醛（MF）树脂衍生的电磁石墨C3N4 /碳泡沫的合成方法

社会要求有效的电磁波（EMW）吸收器要轻巧，吸收带较宽且吸收能力强，以解决过多的电磁辐射。在此，通过将聚合的三聚氰胺甲醛（MF）泡沫浸渍在Fe ₃ O ₄纳米颗粒溶液中，然后在1000°C进行原位热解，制备了超轻磁性石墨状C ₃ N ₄ /碳泡沫（MCMF）。MCMF具有由C ₃ N ₄ /碳和CFe _15.1石墨组成的多孔结构。磁性颗粒（α-Fe，Fe ₃ O ₄和Fe ₃C）在内部骨架表面上形成并改性。MCMF的EMW吸收能力优于不含Fe ₃ O ₄（CMF）的碳化MF泡沫，具有出色的吸收性能，最小RL值为-47.38 dB，匹配厚度薄至3.90 mm。相应的有效吸收带宽高达13.32 GHz。麦克斯韦-瓦格纳-西拉（MWS）极化和残留损耗被证明对这种出色的吸收性能有益。此外，石墨碳₃ N ₄丰富了界面极化效应和电磁匹配效应。微孔结构有利于增加EMW传播，导致内部多重反射和散射，这也有利于EMW衰减。