Abstract

The dielectric properties and chemical inhomogenity of BaTiO3 ceramics sintered with additions of CeO2:1.5TiO2 were investigated using TEM XRD and EDS. Grains had three regions: grain shell severely doped with cerium, grain core BaTiO3 of greater purity, and a concentration gradient region where Curie temperatures were distributed. With decreasing temperatures, the volume fraction of ferroelectric domains in the concentration gradient region increased. Addition of CeO2:1.5TiO2 to BaTiO3 decreased the tetragonality (c/a ratio) and the grain size, and lowered the Curie temperature by approximately 30 ‡C per mol%. Even a small addition of 0.005 mol CeO2:1.5TiO2 to BaTiO3 reduced the average grain size from 25 Μm to less than 1.25 Μm and grains of an average grain size were completely doped with cerium, which explained why the 130 ‡C ferroelectric transition peak did not exist. The inhomogenity of the cerium concentration had a large influence on the dielectric temperature characteristic.

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