Abstract: CaCu_3Ti_4O_(12) (CCTO) ceramics with the addition of SiO_2 were fabricated by the conventional solid-state reaction method. The phase structure, microstructure and the dielectric properties of the CCTO ceramics with different weight percentages of SiO_2 were investigated. There was no solid-state reaction between CCTO and SiO_2 at the sintering temperature, and the SiO_2 additives were observed to be present at the CCTO grain boundaries. It was found that the addition of SiO_2 influenced the microstructure and dielectric properties of the CCTO ceramics. The dielectric constant and loss tangent decreased with the increasing content of SiO_2. Impedance spectroscopy showed that the grain boundary resistance increased due to the addition of SiO_2 to CCTO, which should be main reason for the decrease in the loss tangent of the CCTO ceramics.

Key words: CaCu_3Ti_4O_(12) (CCTO) ceramics with the addition of SiO_2 were fabricated by the conventional solid-state reaction method. The phase structure, microstructure and the dielectric properties of the CCTO ceramics with different weight percentages of SiO_2 were investigated. There was no solid-state reaction between CCTO and SiO_2 at the sintering temperature, and the SiO_2 additives were observed to be present at the CCTO grain boundaries. It was found that the addition of SiO_2 influenced the microstructure and dielectric properties of the CCTO ceramics. The dielectric constant and loss tangent decreased with the increasing content of SiO_2. Impedance spectroscopy showed that the grain boundary resistance increased due to the addition of SiO_2 to CCTO, which should be main reason for the decrease in the loss tangent of the CCTO ceramics.