Conductivity of CeO_2 Modified SrTiO_3 Ceramics

摘要

The CeO_2 modified SrTiO_3 ceramics were prepared by conventional ceramic process. The SrTiO_3 matrix and CeO_2 additive were combined in following system: SrTiOs_3 + x (CeO_2 • TiO_2), where x is the weight percent, of which x ( wt % ) = 2, 5, 10, 15, 20, 25, and 30. The samples were sintered at 1400℃ for an hour in air. The Ce element in SrTiO_3 ceramics is used as an impurity donor. The scanning electron microscopic (SEM) analysis and X-ray diffractive examination of SrTiO_3 ceramics containing CeO_2 indicated that there exists a Ce_2O_3 secondary phase (viz. glass phase) and it had solid solution solubility for impurities which decrease the semiconductive property of SrTiO_3 ceramics, and weaken the oxidation of the surface of grain and thus increase the conductivity of the grains. The semiconducting ceramics prossess lightly distorted cubic structure at room temperature. This paper mainly gives a study of the conductivity of CeO_2 modified SrTiO_3 ceramics.