Enhanced dielectric and conductivity properties of carbon-coated SiC nanocomposites in the terahertz frequency range.

C-coated SiC nanocomposites (SiC@C NCs) were one-step synthesized under a mixture atmosphere of Ar and CH4 using a DC arc-discharge plasma method. The microstructure of the composites could be controlled by varying the volume ratio of Ar and CH4. A strong response to the terahertz (THz) field was observed due to the existence of a graphite shell. The dielectric properties of SiC@C NCs can be enhanced by altering the thickness of the graphite shell. The thicker graphite shell results in a stronger absorption of THz waves and an enhanced real part of conductivity. Fitting the measured conductivity data using the Drude-Smith model reveals that the carrier transport in the SiC@C NCs and its counterpart, the SiC nanoparticles, is dominated by backscattering. The SiC@C NCs with enhanced conductivity are believed to be fundamental materials for various functionalized optoelectronic devices.

Arc-discharge synthesis of nitrogen-doped C embedded TiCN nanocubes with tunable dielectric/magnetic properties for electromagnetic absorbing applications.

The development of novel composites consisting of ceramic and C materials to alleviate increasingly serious electromagnetic radiation is of great significance in the microwave absorption (MA) field, considering their superior anti-oxidation/corrosion performances and good mechanical strength as well as adjustable dielectric loss capabilities. However, it is still a great challenge to broaden their effective absorption bandwidth (reflection loss value ≤-10 dB) and strengthen the absorption intensity simultaneously, which is mostly attributed to the unreliable impedance matching degree at the absorber/air interface. Herein, a feasible strategy is adopted to synthesize TiCN@N-doped C nanocubes, whose low graphitization degree provides desirable impedance matching conditions. In the meantime, masses of core/shell hetero interfaces ensure strong microwave absorption capability. Experimental results reveal that the optimal effective absorption bandwidth of the prepared TiCN@N-doped C nanocubes can reach up to 5.44 GHz with a thickness of 1.88 mm. Our work demonstrates that the TiCN@N-doped C nanocubes have potential for electromagnetic absorbing applications.