Combustion synthesis and microwave absorption property of SiC(Fe) solid solution powder under different reaction time

SiC(Fe) solid solution powders were synthesized via combustion reaction of the Si and C system in a 0.1 MPa nitrogen atmosphere using iron as the dopant and PTFE as the chemical activator, under different reaction time. The microstructures of prepared powders have been characterized by the SEM, EDS, XRD and Raman spectra, respectively. Results indicate that the prepared powders have fine spherical particles and narrow particle size distribution. The electric permittivities of SiC samples were determined in the frequency range of 8.2-12.4 GHz. Results show that the permittivity of SiC decreases with the increasing reaction time. The Fe doped SiC powder with reaction time of 45 min with 2 mm or 2.5 mm thickness exhibit the best microwave absorption properties in the X-band range(8.2-12.4 GHz). A method to predict absorbing property in the other frequency range has been presented.