Temperature Dependent Ac Electric Conduction Of Polymer-Derived Sialcn Ceramics

The polymer-derived SiAlCN ceramic was synthesized by thermal decomposition of an Al-containing polymeric precursor at 1000 °C. The impedance spectra of the ceramic were measured in the frequency range of 20 Hz to 20 MHz at temperatures up to 500 °C. The results show that the conductivity of the material increases gradually with increasing testing temperature and frequency, which behaves a typical NTC characteristic. The overlapping of normalized peaks/lines corresponding to electric modulus/electric conductivity indicates that the material follows an identical conductive mechanism regardless of frequency in the temperature range. The results also reveal that the conductivity followed T−1/4 dependence, corresponding to a 3D hopping process. Analysis of the relationship between σ0 vs T0 reveals that the conductive mechanism is band-tail hopping rather than variable range hopping