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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