Fabrication of lead-free piezoelectric NaNbO₃ ceramics at low temperature using NaNbO₃ nanoparticles synthesized by solvothermal method

Abstract

NaNbO₃ (NN) nanoparticles were successfully synthesized by solvothermal method at 315°C. Some particles have column-like morphology and the others have sphere morphology. The average particle sizes of column-like and sphere particle are 13 and 47 nm, respectively. The NN particles synthesized by the solvothermal method were much smaller than those (average particle size was 590 nm) fabricated by the conventional solid-state method. High-dense (relative density: 95.4%) NN ceramics could be fabricated at low temperature (1150°C) in air using NN nanoparticles obtained by solvothermal synthesis. This sintering temperature is much lower than that (>1350°C) using NN particles obtained by the conventional solid-state reaction method. The fabricated NN ceramics from NN nanoparticles showed a piezoelectric property (d₃₃ = 17 pC/N).