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 (NH4Cl) 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.

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► The B and N codoped SiC has been synthesized successfully by combustion synthesis.
► The B and N codoping leads to the transformation of sp2 bonded carbon to sp3 bonded carbon.
► The dielectric loss mechanism of B and N codoped SiC powder has been presented.