The effect of preheating temperature on microstructure and absorption property of Fe doped β-SiC powders by combustion synthesis

Fe-doped β-SiC powders have been synthesized by overall preheating combustion synthesis under different preheating temperature, using silicon powders and carbon black as the raw materials, iron powder as dopant and PTFE as the chemical activator, respectively. The microstructure of prepared powders has been characterized by XRD, SEM and EDS. The electric permittivity of prepared powder has been determined and the microwave absorption property has been calculated in the frequency range from 8.2GHz to 12.4GHz. Results show that the lattice constants and dielectric property of the prepared β-SiC decrease with increasing preheating temperature. The SiC powder synthesized under preheating temperature of 1300°C with 2mm matching thickness presents the best microwave absorption property in the X-band.