Additive manufacturing of nanocellulose/polyborosilazane derived CNFs-SiBCN ceramic metamaterials for ultra-broadband electromagnetic absorption

Electromagnetic absorption materials that possess efficient absorption performance and broad absorption bandwidth are needed to combat the electromagnetic interference (EMI). SiBCN ceramic-based metamaterials modified with defect-rich carbon nanofibers (CNFs) were developed by combining the additive manufacturing technique and polymer derived ceramic route. Meta-structures were patterned by additive manufacturing of preceramic polymer and followed by thermolysis of the green bodies. Defect-rich CNFs were in-situ generated by thermolysis of nanocellulose introduced into the preceramic green bodies. When the content of cellulose is 6.0 wt % and the annealing temperature is 1200 degrees C, the real and imaginary part of permittivity can reach as high as 17.0 and 7.0, respectively. Cole-Cole circle plots indicates that the CNFs-SiBCN ceramics possess strong polarization capability due to the defect-rich structure of CNFs. At the thickness of 1.8 mm, the minimal reflection loss (RLmin) can reach -20.0 dB while the effective absorption bandwidth reached 2.85 GHz. Through multi-scale (nano and macro) designing, a simulated ultra-broad effective absorption bandwidth of 32.4 GHz from 7.6 GHz to 40 GHz was achieved, where the RLmin reached -46.0 dB at the frequency of 26.8 GHz. This work finds innovative route for the development of ceramic-based broadband electromagnetic absorption materials and new application for the polymer derived ceramics.

Automated summary

This study develops modified SiBCN ceramic-based metamaterials with defect-rich carbon nanofibers (CNFs) using additive manufacturing and polymer derived ceramic route. The materials exhibit high permittivity and strong polarization capability with suitable cellulose content and annealing temperature. Additionally, the materials show excellent absorption performance at different thicknesses.