Synthesis and electromagnetic properties of MWCNT/BMI composites

Multi-walled carbon nanotubes doped with the mixture of iron, cobalt, nickel (m-MWCNTs, m=Fe-Co-Ni) were prepared by a CVD method under nitrogen atmosphere at 1000℃. m-MWCNT/bismaleimide (BMI) composites were prepared with m-MWCNTs as absorber and BMI resin as matrix materials. The microstructure and electromagnetic properties of the m-MWCNT/BMI composites were characterized and analyzed by X-ray diffraction (XRD) apparatus, scanning electron microscopy (SEM) and the vector network analyzer. The results show that m-MWCNTs as absorber have both dielectric loss and strong magnetic loss. When the content of m-MWCNTs is up to 8 wt% and the thickness of the composite is 2 mm, the reflection loss of this composite reaches to -12.63 dB at 12.96 GHz, and also show an increasing trend, indicating the well-matched electromagnetic parameters.