7.
The solid solutions of Ba-doped SrBi
2Ta
2O
9 layered perovskite ceramic powders have been successfully prepared via a two-step process using BiTaO
4 as a precursor. The lattice constants of the solid solutions monotonically increase with increasing barium-ion content. The sinterability of (Sr
1–xBa
x)Bi
2Ta
2O
9 powders is significantly improved by increasing the barium-ion content. When the specimens with high barium-ion contents are sintered at 1100°C, they thermally decompose to form rod-like grains and the matrix expands, leading to a lower density. The addition of barium ions to SrBi
2Ta
2O
9 also results in significant variation in the morphology of the sintered specimens and the occurrence of
c-axis preferred orientation which is ascribed to the anisotropic growth of plate-like grains. The precise control of the barium-ion content as well as the sintering conditions is critical for obtaining densified barium-ion doped SrBi
2Ta
2O
9 ceramics with a pure, layered perovskite structure.
相似文献