A cost-effective approach to improve dielectric property of SiC powder

The SiC/N solid solution powders were synthesized via combustion reaction of Si/C system in Ar atmosphere, using NH₄Cl as the dopant and polytetrafluoroethylene as the chemical activator. XRD, SEM, EDS and Raman spectra were utilized in analyzing phases, morphology, and chemical composition. Results indicate that no Si₃N₄ phase is generated and lattice constant of the prepared powders decreases with increasing NH₄Cl content due to the N doping arising from decomposition of NH₄Cl. The electric permittivities of prepared powders were determined in the frequency range of 8.2-12.4 GHz. The electric permittivities of prepared powders increase with increasing NH₄Cl content. The mechanism of dielectric loss by doping has been discussed.