Enhanced microwave absorption properties of polymer-derived SiC/SiCN composite ceramics modified by TiC

Porous SiCN(Ti) composite ceramics with good microwave absorbing performance were fabricated by pyrolysis of solid polysilazane modified by tetrabutyl titanate. The introduction of Ti not only acted as active filler to react with free carbon in the matrix to form TiC, but also played the role as catalyst to promote the formation of SiC nanowires. Finally, SiCN(Ti) composite ceramics formed a microstructure containing multi-nanophases and multi-nano heterogeneous interfaces when annealing temperature reached 1500 degrees C. The complex microstructure annealed at 1500 degrees C made composite ceramics have good matching impedance, as well as greatly increase the interfacial polarization loss and dipole polarization loss. As a result, the TiC/SiC/SiCN composite ceramics showed the excellent performance of electromagnetic wave absorption in X band. The minimum reflection loss (RL) of samples was - 17.1 dB at the thickness of 1.9 mm, and the maximum effective absorption bandwidth (EAB) of composite ceramics was 3.2 GHz when the thickness of sample was 2.1 mm, which exhibited a promising prospect as a structural and microwave absorbing integration material.