A simple method to improve dielectric property of SiC powder

Aluminum-doped silicon carbide powders were synthesized via solid state reaction of Si/C system at 1600□ in Ar atmosphere, using aluminum powder as the dopant, which were investigated by X-ray diffraction (XRD) and scanning electronic microscope (SEM). The electric permittivities of the prepared powders were determined in the frequency range of 8.2-12.4 GHz. The dielectric real part ε' and imaginary part ε″ of undoped powder have minimum values (ε' = 5.5-5.3, ε″ = 0.23-0.20), and increase with increasing aluminum content. The mechanism of dielectric loss by doping has been discussed.