Single-source-precursor synthesized SiCN/MWCNT nanocomposites with improved microwave absorbing performance

To improve the microwave absorbing performance, SiCN/MWCNT nanocomposites with different carboxylic functionalized multi-walled carbon nanotubes (MWCNT-COOH) contents (0 wt%, 2 wt%, 4 wt% and 8 wt%) were synthesized by single-source-precursor poly(methylvinyl)silazane (HTT1800) and polymer-derived ceramics method. The microwave absorbing performance of SiCN/MWCNT nanocomposites were investigated in the frequency range of 8.2–12.4 GHz with the thickness varied from 3.0 to 5.0 mm. The results showed that the minimum reflection loss (RL_min) of the sample of 10 wt% SiCN/MWCNT-8 mixed with paraffin wax reached − 30.34 dB with the thickness of 4.5 mm in the frequency of 11.45 GHz. The reason was that the introduction of MWCNT-COOH increased the interfacial polarization loss and the conduction loss of nanocomposites, improving microwave absorbing performance. The findings demonstrated that the synthesized SiCN/MWCNT nanocomposites possessed promising prospects as microwave absorbing materials.