Preparation and dielectric property of B and N-codoped SiC powder by combustion synthesis

B and N-codoped SiC powder has been prepared by combustion synthesis in a nitrogen (N₂) or argon (Ar) atmosphere, using silicon powder and carbon black as raw materials, boron (B) powder and ammonium chloride (NH ₄Cl) dopants and polytetrafluoroethylene (PTFE) as the chemical activator, respectively. The synthesized powders have been characterized by XRD, SEM and Raman spectra. Results indicate that the prepared products are β-SiC powders with narrow size distribution. The electric permittivities of prepared SiC powders have been determined in the frequency range of 8.2-12.4 GHz. The dielectric real part and dielectric loss decrease in the N₂ atmosphere and decrease further in the Ar atmosphere with the molar ratio of B to NH₄Cl increasing.