Solid-state reaction synthesis of sodium niobate (NaNbO3) powder at low temperature

A modified solid-state reaction was applied to produce lead-free piezoelectric sodium niobate (NaNbO3) powders. The mixture of Na2C2O4 and Nb2O5 was identified by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). The powders were characterized using a scanning electron microscope (SEM) and the X-ray diffraction technique (XRD). The SEM image suggested that the particle size of the powders obtained ranged from 180 to 360 nm. The XRD pattern showed that the pure perovskite phase of NaNbO3 could be synthesized at the low temperature of 475 °C for 1 h, with an average crystallite size of 31.45 ± 5.28 nm. This temperature was about 300 °C lower than that when using the conventional solid-state method with Na2CO3 as reactant, which resulted in a cost-, energy-, and time-saving method.