电介质的衍生对导数介电分析方法及其应用

Varied high-temperature and low-frequency dielectric characteristics are commonly detected in deteriorated engineering dielectrics, including increased dielectric permittivity, loss factor, etc. Consequently, a clear insight into those dielectric responses is of great significance to further degradation investigation and condition assessment. However, the relaxations are usually coupled with DC conductance so that they are easily covered by conductance component in low-frequency range, thus further studies on them are hardly to be carried out. What is worse, DC conductance is sometimes mistaken for a relaxation process in some dielectric spectra due to similar temperature and frequency dependence. Therefore, we proposed an extended derivative spectroscopy which only remains relaxations but excludes DC conductance. Taking three typical engineering dielectrics, such as poxy, oil-impregnated paper, and ZnO ceramics, as examples, we successfully characterized new low-frequency relaxations from the covered DC conductance via the improved spectra. Moreover, we discussed the physical mechanism of the relaxations in the three different dielectrics respectively. The results provide a potential approach for further manipulating and assessing properties of engineering dielectrics.