Cai Zhixin, Su Lei, Wang Hongjie, Niu Min, Tao Liting, Lu De, Xu Liang, Li Mingzhu, Gao Hongfei
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
ACS Appl Mater Interfaces. 2021 Apr 14;13(14):16704-16712. doi: 10.1021/acsami.1c02906. Epub 2021 Apr 2.
Lightweight electromagnetic (EM) wave absorbers made of ceramics have sparked tremendous interest for applications in EM wave interference protection at high temperatures. However, EM wave absorption by pure ceramics still faces huge challenges due to the lack of efficient EM wave attenuation modes. Inspired by the energy dissipation mechanism during fracture of lobster shells with a soft and stiff multilayered structure, we fabricate a high-performance EM wave absorption ceramic aerogel composed of an alternating multilayered wave transparent SiN (N) layer and wave absorption SiC (C) layer by a simple restack method. The obtained N/C aerogel shows ultralow density (∼8 mg/cm), broad effective absorption bandwidth (8.4 GHz), strong reflection loss (-45 dB) at room temperature, and excellent EM wave absorption performance at high temperatures up to 1000 °C. The attenuation of EM wave mainly results from a "reflection-absorption-zigzag reflection" process caused by the alternating multilayered structure. The superior absorption performance, especially at high temperatures, makes the N/C aerogel promising for next-generation wave absorption devices served in high-temperature environments.
由陶瓷制成的轻质电磁波吸收体在高温下的电磁波干扰防护应用中引发了极大的关注。然而，由于缺乏有效的电磁波衰减模式，纯陶瓷的电磁波吸收仍面临巨大挑战。受具有软硬多层结构的龙虾壳断裂过程中的能量耗散机制启发，我们通过一种简单的重新堆叠方法制备了一种高性能的电磁波吸收陶瓷气凝胶，它由交替的多层波透明SiN（N）层和波吸收SiC（C）层组成。所制备的N/C气凝胶表现出超低密度（约8毫克/立方厘米）、宽有效吸收带宽（8.4吉赫兹）、室温下强反射损耗（-45分贝）以及在高达1000℃的高温下优异的电磁波吸收性能。电磁波的衰减主要源于交替多层结构引起的“反射-吸收-曲折反射”过程。这种优异的吸收性能，尤其是在高温下的性能，使得N/C气凝胶在下一代高温环境下的波吸收器件中具有广阔前景。
