RTGG法による結晶配向性CaBi_4Ti_4O_<15>およびSrBi_4Ti_4O_<15>の作製におけるヘテロ凝集の影響 Effect of Heterocoagulation on the Preparation of Textured CaBi_4Ti_4O_<15> and SrBi_4Ti_4O_<15> Made by Reactive-Templated Grain Growth Process
Textured CaBi<SUB>4</SUB>Ti<SUB>4</SUB>O<SUB>15</SUB> and SrBi<SUB>4</SUB>Ti<SUB>4</SUB>O<SUB>15</SUB> 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 Bi<SUB>2</SUB>O<SUB>3</SUB> and CaCO<SUB>3</SUB> or SrCO<SUB>3</SUB> 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.
粉体および粉末冶金 55(4), 270-275, 2008-04-15
Japan Society of Powder and Powder Metallurgy