Preparation of crystal-axis-oriented barium calcium titanate plate-like particles and its application to oriented ceramic

A novel two-step process has been developed for the preparation of Ba _0.9Ca_0.1TiO₃ plate-like grains with [110]-crystal-axis-orientation. In the first step, plate-like particles of a layered titanate H_1.07Ti_1.73O₄ are solvothermally treated in a Ba(OH)₂-Ca(OH)₂ mixed solution, and then in the second step, heat-treat the solvothermally treated sample to complete the formation reaction of Ba_0.9Ca _0.1TiO₃. The formation reaction and nanostructure of the Ba_0.9Ca_0.1TiO₃ plate-like grains were characterized using X-ray diffraction, FE-SEM, TEM, and SEAD. The Ba _0.9Ca_0.1TiO₃ plate-like grains are constructed from spherical nanoparticles with particle size of about 10-20 nm. The spherical nanocrystals in each plate-like grain arrange in the same crystal-axis- orientation direction, which presented a diffraction pattern similar to the single crystal. The Ba_0.9Ca_0.1TiO₃ plate-like grains were utilized to fabricate an oriented Ba_0.9Ca _0.1TiO₃ ceramic to demonstrate the potential application of the plate-like grains, and the [110]-oriented Ba_0.9Ca _0.1TiO₃ ceramic with a high degree orientation of F ₁₁₀ = 76% and small grain size of about 1-2 μm was obtained.