Study on the Granularity Effect on Electromagnetic Wave Absorbing Properties of Ni-SiC Composites

In order to solve electromagnetic compatibility and interference problems in electromagnetic defence field, the Ni-SiC. composites were prepared. The effects of Ni-SiC particles with different granularities on absorbing properties at the frequency range from 8 GHz to 18.4 GHz and their absorption mechanism were studied. The research results show that the changes of granularities of Ni-SiC particles have obvious influences on absorbing properties. When the granularities of the same kind of particles reduce to a certain scale, the test results show different absorbing properties. In the Ni-SiC composites, the absorbing properties of 5.48 mum SiC are better than those of 10.39 mum SiC and 21 mum SiC under the same composition. It is found that the minimum reflectivity of 5.48 mum SiC is -16 dB and the bandwidth for -10 dB is 3 GHz. The absorption mechanism of the Ni-SiC composites is magnetic and dielectric loss and scattering effect.