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

• Precursor particles with acicular morphology were hydrothermally synthesized.
• The growth temperature effects the particle morphology, composition and structure.
• Particles can be fully transformed to NaNbO3 while retaining their morphology.
• Acicular NaNbO3 particles were used as templates in the fabrication of 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⋅13H2O particles with rod-like morphology were synthesized at 120 °C. Particles with needle-like morphology and Na2(Nb2O6)(H2O) phase started to form at temperatures of 130 °C and above. Synthesis at 150 °C yields particles with totally needle-like morphology and consisting entirely of the Na2(Nb2O6)(H2O) phase. Sodium niobate–NaNbO3 particles with cubic morphology were synthesized at temperatures of 160 °C and above. Rod-like and needle-like morphology was retained even after annealing at 400 °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.

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