Wave-absorbing property of SiC (N) nano powder

Some improvements are needed to increase the SiC's wave-absorbing ability. A method is used to dope SiC with other atoms. Nano SiC (N) powders are synthesized with the chemical vapor deposition (CVD) method. The formed SiC (N) nano powder is considered as SiC nano crystalline doped with nitrogen atoms. The SiC (N) nano powder is spherical and loosely agglomerates into particles within a range of 20-30 nm. The nitrogen content of the nano SiC (N) powder can be adjusted by varying the flow rate of NH₃ in the preparation process. The microwave permittivity of the mixture of SiC (N) nano powder with paraffin wax was measured. The results show that the permittivity of the mixture change with the composition of SiC (N) nano powder. Both the permittivity and the dielectric loss of the mixture decreased with the increase of N mole content. Based on the measured data, double-layer wave-absorbing materials with 3 kinds of SiC (N) nano powder were designed. The thickness of the materials is 3 mm. The change of reflectivity with the frequency for these materials is also illustrated. It shows that the reflectivity decreases with the increase of N content in the SiC (N) nano powder.