Eggplant-derived SiC aerogels with high-performance electromagnetic wave absorption and thermal insulation properties
Eggplant-derived SiC aerogels with high-performance electromagnetic wave absorption and thermal insulation properties
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具有高性能电磁波吸收和隔热性能的茄子源碳化硅气凝胶
DOI：
10.1016/j.cej.2019.05.076
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发表时间：
2019-10-01
影响因子：
15.1
通讯作者：
Wang, Zhijiang
中科院分区：
文献类型：
--
作者：
Liang, Caiyun;Wang, Zhijiang
通过直接石墨化和随后的碳热还原，从天然茄子中获得具有三维结构和原位生长的SiC纳米线的轻质和坚固的碳化硅（SiC）气凝胶。通过用一维SiC纳米线装饰SiC框架来实现有效的协同作用，其赋予气凝胶优异的电磁（EM）波吸收、热绝缘和机械性能。高度多孔的、相互连接的SiC网络促进了渗透的电磁波的多次反射-吸收效应，并延长了样品中的热传输路线。SiC纳米线由许多层错和异质结组成，在耗散电磁能量、阻碍热传递和增强SiC骨架方面起着关键作用。考虑到其97.6%的孔隙率，SiC气凝胶在2 mm厚度下显示出-43dB的最小反射率和4GHz的有效带宽。原位生长的SiC纳米线使SiC气凝胶的压缩应力显著增加到2.12 MPa，这是来自茄子的碳气凝胶的压缩应力的近50倍。此外，SiC气凝胶显示出0.035 W/m. K的非常低的热导率。这些结果表明，所开发的SiC气凝胶是优秀的材料，具有潜在的应用在航空航天领域的高性能电磁吸收和隔热。
Lightweight and strong silicon carbide (SiC) aerogels with a three-dimensional architecture and in situ grown SiC nanowires are obtained from natural eggplants by direct graphitization and subsequent carbothermal reduction. Effective synergism is achieved by decorating the SiC frameworks with one-dimensional SiC nanowires, which impart the aerogels with excellent electromagnetic (EM) wave absorption, thermal insulation, and mechanical properties. Highly porous, interconnected SiC networks facilitate the multiple reflection-absorption effects of infiltrated EM waves and extend the routes of heat transmission in the samples. SiC nanowires, which consist of numerous stacking faults and heterojunctions, play key roles in dissipating EM energy, obstructing heat transfer, and reinforcing the SiC skeleton. Given their 97.6% porosity, the SiC aerogels show a minimum reflection of -43 dB and effective bandwidth of 4 GHz at 2mm thickness. The in situ grown SiC nanowires substantially increase the compressive stress of the SiC aerogels to 2.12 MPa, which is nearly 50-fold than that of carbon aerogels derived from eggplants. Moreover, the SiC aerogels show a very low thermal conductivity of 0.035 W/m.K. These results indicate that the developed SiC aerogels are outstanding materials with potential applications in high-performance EM absorption and thermal insulation in the aviation and aerospace fields.