Textured CaBi4Ti4O15 and SrBi4Ti4O15 ceramics have been prepared by the reactive-templated grain growth process. When slurries for tape casting are prepared using a solvent, binder, and plasticizer, large agglomerates are formed in the slurries by heterocoagulation between Bi2O3 and CaCO3 or SrCO3 particles. These agglomerates melt between 800° and 850°C, and the melt penetrates into surrounding powder layers, leaving large voids. Sintering at high temperatures cannot eliminate these voids, resulting in a low density. Furthermore, the voids disturb the alignment of platelike particles surrounding the voids. The use of dispersant in the preparation of the slurries suppresses the formation of the agglomerates, and dense, highly-textured materials are obtained.
