Two-step Synthesis of Platelike Potassium Sodium Niobate Template Particles by Hydrothermal Method

Two-step hydrothermal synthesis of platelike potassium sodium niobate (K, Na)NbO3 (KNN) template particles was investigated. Platelike K4Na4Nb6O19 center dot 9H(2)O (KNN-hydrate) particles were synthesized in 4 mol/L aqueous alkali at 150 degrees C by the sodium dodecyl benzene sulfonate (SDBS) surfactant-assisted hydrothermal method, which were used as crystal nucleus in the second step of hydrothermal synthesis. The two-step synthesized KNN-hydrate particles with 0.6 mu m thickness and 7 mu m width were prepared at 80 degrees C after 10 h of the second step. After calcination of the KNN-hydrate particle at 600 degrees C, platelike KNN particles were obtained, which were used as templates for textured ceramics. Particles obtained by the two-step synthesis showed regular morphology and uniform distribution, with a marked improvement in grain size.