Abstract
Dielectric ceramics with high permittivity and low sintering temperature are of great interest for many applications. In this study, BaTiO 3 ceramics are doped with 9 mol% LiF and also with small additions of Nb 2 O 5 and Dy 2 O 3 , and then sintered in various atmospheres. The frequency dependence of the dielectric constant and the dissipation factor are measured in the frequency range 100Hz-100KHz. A reducing atmosphere or a catalytic agent can cause the LiF-doped BaTiO 3 ceramics to form GBBL capactiors. The maximum dielectric constant obtained is about 14,000 at 100Hz for 4 mol% LiF doped BaTiO 3 with 0.5 mol% Nb 2 O 5 sintered in CO CO 2 . For sintering in air or in a weakly reducing atmosphere, the dielectric constant increases as the Nb 2 O 5 content is raised to 0.4 mol% and then decreases significantly at 0.5 mol% Nb 2 O 5 . The Curie temperature is shifted downward for samples with LiF and Nb 2 O 5 dopants, especially for sintering in CO CO 2 . The Curie temperature shift as well as the resulting small grain size enhances the dielectric constant at room temperature. The sintering shrinkage measurement is also performed to investigate the densification behavior with various dopants. © 1988.