Previous research has fully demonstrated that the core–shell spherical structure can facilitate multiple reflection within the cavity and provide polarization relaxation at the heterogeneous interfaces. In this study, double-shell nitrogen-doped carbon-Fe3C-Fe (NC-Fe3C-Fe, referred to as CFF) nanospheres composed of hollow NC-Fe3C and solid NC-Fe3C/Fe nanospheres are synthesized in an interconnected three-dimensional structure. The double-shell is composed of nitrogen-doped carbon outer shells and Fe3C inner shells, derived from the carbonization of polydopamine (PDA) and controllable etching of the Fe nanotemplates in the PDA@Fe. In this strategy, the carbon shells provide dielectric loss, and the Fe3C and Fe contribute to magnetic loss, bringing about a magnetic-electric synergistic effect on effective electromagnetic wave absorption (EMA). By adjusting the thickness of the carbon shells and the etching time of the Fe, the CFF achieves a minimum reflection loss of −74.00 dB at a thickness of 1.91 mm, with an effective absorption bandwidth of 5.04 GHz. In addition, by the radar cross-section (RCS) scattering simulation, the RCS value at a scattering angle of 0° decreased by 32.06 dBm2, confirming an excellent EMA capability in practical far-field applications. This study provides an effective strategy for the application of core–shell and double-shell structures in the EMA materials.

中文翻译：

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空心和固体组合双壳氮掺杂碳-Fe3C-Fe 纳米球，具有可调壳层厚度和磁性成分，可增强电磁波吸收


以前的研究已经充分证明，核壳球形结构可以促进腔内的多重反射，并在非均质界面处提供极化弛豫。在本研究中，由空心 NC-Fe3C 和固体 NC-Fe3C/Fe 纳米球组成的双壳氮掺杂碳-Fe3C-Fe （NC-Fe3C-Fe，简称 CFF） 纳米球在互连的三维结构中合成。双壳层由氮掺杂碳外壳和 Fe3C 内壳组成，来源于聚多巴胺 （PDA） 的碳化和PDA@Fe中 Fe 纳米模板的可控刻蚀。在这种策略中，碳壳提供介电损耗，而 Fe3C 和 Fe 导致磁损耗，从而对有效电磁波吸收 （EMA） 产生磁电协同效应。通过调整碳壳的厚度和 Fe 的蚀刻时间，CFF 在 1.91 mm 的厚度上实现了 -74.00 dB 的最小反射损耗，有效吸收带宽为 5.04 GHz。此外，通过雷达散射截面 （RCS） 散射仿真，散射角为 0° 时的 RCS 值降低了 32.06 dBm2，证实了在实际远场应用中出色的 EMA 能力。本研究为核壳和双壳结构在 EMA 材料中的应用提供了一种有效的策略。