The hierarchical porous SiOC ceramics (HPSCs) have been prepared by the pyrolysis of precursors (the mixture of dimethicone and KH-570) and polyacrylonitrile nanofibers (porous template). The HPSCs possess hierarchical porous structure with a BET surface area of 51.4 m2/g and have a good anti-oxidation property (only 5.1 wt.% weight loss). Owing to the porous structure, the HPSCs deliver an optimal reflection loss value of - 47.9 dB at 12.24 GHz and an effective absorption bandwidth of 4.56 GHz with a thickness of 2.3 mm. The amorphous SiOC, SiOx, and free carbon components within SiOC make contributions to enhancing dipolar polarization. Besides, the abundant interfaces between SiOC and carbon nanofibers (CNFs) are favorable for improving interfacial polarization. The conductive loss arisen from cross-linked CNFs can also boost the microwave absorption performance.

中文翻译：

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碳纳米纤维支撑分层多孔 SiOC 陶瓷实现高效微波吸收。


通过前驱体（聚二甲基硅氧烷和KH-570的混合物）和聚丙烯腈纳米纤维（多孔模板）的热解制备了分级多孔SiOC陶瓷（HPSC）。 HPSCs具有分级多孔结构，BET比表面积为51.4 m2/g，具有良好的抗氧化性能（重量损失仅为5.1 wt.%）。由于多孔结构，HPSC 在 12.24 GHz 时的最佳反射损耗值为 - 47.9 dB，有效吸收带宽为 4.56 GHz，厚度为 2.3 mm。 SiOC 中的非晶态 SiOC、SiOx 和游离碳成分有助于增强偶极极化。此外，SiOC和碳纳米纤维（CNF）之间丰富的界面有利于改善界面极化。交联 CNF 产生的传导损耗也可以提高微波吸收性能。