Abstract: Two special rare earth elements cerium and europium were chosen to conduct chemical modification of the BaTiO₃ structure. The cold-pressing ceramic processing technique was used to prepare barium titanate ceramics doped with Ce at Ti sites and with Eu at Ba sites on the base of formulas Ba(Ti_1-xCe_x)O₃(x=0.05, 0.10)(CBT) and(Ba_1-yEu_y)Ti_1-y/8O₃(y=0.05, 0.10)(EBT). Associated with structures and microstructures, the effects of cerium and europium doping on dielectric properties of BaTiO₃ ceramics were discussed. The CBT ceramics exhibit a pseudo-cubic perovskite structure, while the EBT ceramics exhibit a tetragonal perovskite structure with the exception of the existence of a small percentage of the Eu₂Ti₂O₇ phase. The Curie peak of BaTiO₃ shifts towards room temperature at rates of 3 ℃/mol Ce atoms and 10 ℃/mol Eu atoms(Eu≤5%), respectively. Compared with the CBT ceramics, the EBT ceramics show significant advantages, such as a narrow fine grain size distribution(1 μm), a lower porosity and a higher density(5.85 g/cm³), more stable dielectric-temperature dependence(ε'=1600-1800 at t＜50 ℃) and a lower dissipation factor(＜0.05). The stability of dielectric constant with frequency in BaTiO₃ can extend to 10⁷ Hz due to Ce and Eu doping.

Key words: Cerium, Europium, Barium titanate, Cold-pressing technique, Dielectric constant