Microwave dielectric properties of SiC(B) solid solution powder prepared by combustion synthesis

B-doped SiC powders were synthesized via combustion reaction of the Si/C system in a 0.1MPa nitrogen atmosphere, using polytetrafluoroethylene as the chemical activator and boron oxide as the dopant. The prepared powders have fine spherical particles and narrow particle size distribution. The electric permittivities of β-SiC samples were determined in the frequency range of 8.2-12.4 GHz. Results show that the β-SiC doped with 5% B₂O₃ has the highest real part ε' and imaginary part ε '' of permittivity. The mechanism of dielectric loss by doping has been discussed.