Influence of SiO2-adding on microstructure and dielectric properties of (In0.5Nb0.5)0.05Ti0.95O2 ceramics

Abstract

(In0.5Nb0.5)xTi1-xO12 (INTO) ceramics exhibit the unusual dielectric properties of giant dielectric constant and good stabilities, but their low-frequency dielectric loss is relatively large, and the sintering temperature is too high, which are very disadvantageous for practical applications. According to internal barrier layer capacitance effect, which seems to be the most plausible mechanism of the unusual dielectric properties, constructing insulating phase boundaries in INTO ceramics is an effective way to reduce their low-frequency dielectric loss. In this paper, SiO2 was added to INTO ceramics, because, on the one hand, the insulating phase boundaries could be constructed by SiO2, on the other hand, SiO2 could play the role of sintering agent to reduce the sintering temperature. Therefore, the SiO2/INTO ceramics were prepared by solid-state reaction, and their crystalline structures, microstructures, and electrical properties were analyzed. Compared to previous reports, the low-frequency dielectric loss of SiO2/INTO ceramics after annealing, which were sintered at a lower temperature of 1300 °C for a shorter time of 5 h, decreases substantially. The reason was discussed.