Sodium niobate particles with controlled morphology synthesized by hydrothermal method and their use as templates in KNN fibers

Sodium niobate - NN (NaNbO3) powders were synthesized by hydrothermal process to be used as template particles in the fabrication of textured lead free piezoelectric ceramics. Sodium hexaniobate-Na8Nb6O19 center dot 13H(2)O particles with rod-like morphology were synthesized at 120 degrees C. Particles with needle-like morphology and Na-2(Nb2O6)(H2O) phase started to form at temperatures of 130 degrees C and above. Synthesis at 150 degrees C yields particles with totally needle-like morphology and consisting entirely of the Na-2(Nb2O6)(H2O) phase. Sodium niobate-NaNbO3 particles with cubic morphology were synthesized at temperatures of 160 degrees C and above. Rod-like and needle-like morphology was retained even after annealing at 400 degrees C for 1 h. A preliminary study was also done to integrate these anisometric template particles in the preparation of textured potassium sodium niobate (KNN) fibers. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.