Examination of selectivity of templates for the textured potassium sodium niobate ceramics

To achieve the surface-orientation-controlled microstructure of K_0.5Na_0.5NbO₃, not only the template must exhibit the high anisotropy like a plate-shape but the reactive stability as well as the crystallographic coherency between the template and the K_0.5Na_0.5NbO₃ must be carefully considered. In this work, we focused on what kinds of ceramics are suitable for the fabrication of the surface-orientation-controlled K_0.5Na_0.5NbO₃. First of all, BaTiO₃, SrTiO₃, Ba(Zr_0.1Ti_0.9)O₃, KNbO₃, NaNbO₃, KTaO₃ and NaTaO₃ were chosen as the candidates in the regard of the crystallographic coherency. To verify the chemical stability between candidate ceramics and K_0.5Na_0.5NbO₃, the prepared candidate ceramic bulks were embedded by the K_0.5Na_0.5NbO₃ powder, they were annealed at 1100 °C, and then the interface regions between candidate ceramics and K_0.5Na_0.5NbO₃ were investigated using Secondary Electron Microscopy (SEM) equipped with Energy Dispersive Spectrometer (EDS). From these experimental results, BaTiO₃, SrTiO₃, Ba(Zr_0.1Ti_0.9)O₃, KNbO₃ and NaTaO₃ were found to be not appropriate for the templates for the tailoring of K_0.5Na_0.5NbO₃, while the NaNbO₃ and KTaO₃ showed a good crystallographic coherency and a chemical stability with K_0.5Na_0.5NbO₃.