High Dielectric Constant X7r Capacitor Dielectric Ceramic Material

The dielectric properties of the Barium Titanate ceramic with X7R behavior have been studied in this thesis. The basic composition of this kind of dielectric can be expressed as BaTiOs-NbiOs-CosO-t. The solubility or segregation of the acceptors or donors and their effects on the properties of the ceramic dielectric are discussed, especially, the relationships of the composition, process, micro-structure and the electrical properties of the ceramic are systematically investigated. The experiment results show that, by doping with suitable amount of additives such as ?03, Dy2C"3, CeO2, MnOi and careful control of key factors of preparation process, the properties of ceramic dielectric can be obtained, such as the reduction of dielectric loss, the broad of Curie peak and the enhancement of dielectric constant.The dielectric behavior of the ceramic capacitor reached the level as follows: E25r>5000, p>10'*Qcm, tg5<1.5%,Eb (V/mm) > (8KV/mm) [DC], Eb (V/mm) >(3.6KV/mm)[AC], AC/C2?c(-55℃? 125℃ )