Porous SiOC ceramic was successfully prepared by pyrolysis of dimethylsilicone oil, silane coupling agent and melamine foam. The microwave absorbing properties of porous SiOC were studied for the first time. At the matching layer thickness of 3.0 mm, the paraffin-based composite with porous SiOC displays a minimum reflection coefficient (RC) of −39.13 dB (11.76 GHz) and an effective absorption bandwidth (EAB) of 4.64 GHz which are much larger than that of paraffin-based composite with ordinary SiOC. It is found that the porous structure of SiOC is crucial to achieve its high microwave absorption performance by improving both the polarization loss and conduction loss. The enhanced polarization loss is originated from the dipole polarization and interfacial polarization, while the improvement of conduction loss is attributed to the carbon skeleton of porous SiOC. These results indicate that porous SiOC ceramic is a promising candidate for high-performance ceramic-based microwave absorbing materials.

通过对二甲基硅油，硅烷偶联剂和三聚氰胺泡沫进行热解，成功制备了多孔SiOC陶瓷。首次研究了多孔SiOC的微波吸收性能。在3.0 mm的匹配层厚度下，具有多孔SiOC的石蜡基复合材料的最小反射系数（RC）为−39.13 dB（11.76 GHz），有效吸收带宽（EAB）为4.64 GHz，远大于其普通SiOC的石蜡基复合材料的制备。发现SiOC的多孔结构对于通过改善极化损耗和传导损耗两者来实现其高微波吸收性能至关重要。极化损耗的增加源自偶极极化和界面极化，传导损耗的改善归因于多孔SiOC的碳骨架。这些结果表明，多孔SiOC陶瓷是高性能陶瓷基微波吸收材料的有希望的候选者。