Temperature-dependent electrical and dielectric behavior of polymer-derived SiAlCN ceramics

Polymer-derived SiAlCN ceramics as sensing materials are promising materials for wireless temperature sensors to achieve application in high-temperature harsh environments. However, limited understanding for the electric and dielectric properties of SiAlCN ceramics restricts the development of wireless sensors. Herein, the electrical and dielectric properties of polymer-derived SiAlCN ceramics pyrolyzed at different temperatures are investigated systemically. The results reveal that the electric resistance of the free-carbon phase and amorphous SiAlCN ceramic phase are comparable, however, the dielectric constant of the ceramic phase is much higher than that of the free-carbon phase. The maximum dielectric constant can reach up to 2.4E+5. Furthermore, the detailed mechanism analysis reveals that the SiAlCN ceramics with different pyrolysis temperatures all obey the same relaxation process, which is interfacial polarization and non-Debye relaxation. The deep understanding of the dielectric property of polymer-derived SiAlCN ceramics is very practical to design wireless sensors for potential applications in high-temperature and harsh environments.