Complex impedance spectra of polymer-derived SiC annealed at ultrahigh temperature

This study reports the complex impedance and alternative current conductivity of polymer-derived ceramic SiC (PDC-SiC) annealed at ultrahigh temperatures. The PDC-SiC shows an inductive response when annealed at temperatures of 1700°C-1900°C due to the percolation of turbostratic carbon. The material returns to a capacitive response at an annealing temperature of 2000°C due to the dissolution of carbon into the SiC lattice. The electrical resistance of the carbon phase decreases with the increase in annealing temperature. These results provide new insights into the effects of processing temperature on microstructure evolution and electrical and dielectric property development of the PDC-SiC ceramic system.