Youzhi Wang,Xue Guo,Yurun Feng,Xiao Lin,Hongyu Gong
Ferreous polymer-derived SiCN ceramics (PDCs-SiCN(Fe)) were successfully synthesized by precursor conversion method. The phase composition and microstructure of the obtained products were investigated by XRD , SEM and TEM . The result indicated a mainly amorphous structure with a few α-Fe,and graphite phases in the gaps. The conductivity, electromagnetic parameters and wave absorbing properties of the prepared ceramics were studied at the frequency band from 2 to 18 GHz. The reflectance of PDCs-SiCN(Fe) was about −10 dB (> 90% absorption) in the range of 4–16 GHz with 25 wt% nano-Fe 2 O 3 addition at the thickness 8 mm. The maximum value of dielectric and magnetic loss angle tangent was about 1.5, indicating PDCs-SiCN(Fe) ceramics possessed good absorption performance .
Strontium ferrites/graphene (SrFe12O19/G) composites were synthesized by a facile one-step surfactant assisted hydrothermal method. The structure, magnetic properties and electromagnetic parameters of the as-prepared composites were evaluated. Uniform SrFe12O19 nanoparticles with a diameter of 60–70 nm were well distributed on the graphene. The formation of SrFe12O19 nanoparticles and the reduction of graphene oxide were accomplished simultaneously. The re-stacking of graphene sheets and the aggregation of SrFe12O19 nanoparticles were inhibited. The as-obtained composites exhibited better absorbing properties than the pristine SrFe12O19 particles due to the synergistic effect of SrFe12O19 and graphene. The minimum reflection loss (RL) of SrFe12O19/G composites with the thickness of 3 mm reached −34.8 dB at 13.6 GHz, and the effective absorption bandwidth (RL < −10 dB) was 5.7 GHz. However, the minimum RL of the SrFe12O19 particles only reached −13.5 dB, and the effective absorption bandwidth was 4.6 GHz. A possible mechanism for the enhanced absorbing performance was proposed.
危险品化学品经营许可证（带存储）