Testing media influences on the dielectric properties of lead sodium niobate glass-ceramics

The influences of testing media on the breakdown strength (BDS) and dielectric properties of glass-ceramics in the Na2O–PbO–Nb2O5–SiO2 system were investigated. This work was brought out by consideration of the electric conductance, dielectric constant and breakdown strength of different testing media, which are the main reasons for the different dielectric properties and BDS values of the identical dielectric sample. Leakage current (LC), P–E hysteresis loops, C–V curves and breakdown tests show that the BDS and the dielectric properties of the glass-ceramics could be optimized through using appropriate testing medium. It turns out that three favorable characteristics of the dielectric composites could be optimized in silicon/castor oil mixture: the lowest LC (LC = 6.72 × 10−6 A, at E = 25 kV/mm), thin P–E hysteresis loops and low hysteresis. Furthermore, the highest BDS of the glass-ceramic was obtained in glycerin (BDS = 105.6 kV/mm with sample thickness of 0.108 mm) compared to other media.