Low-Temperature Preparation of K_xNa_(1-x)NbO_3 LeadFree Piezoelectric Powders by Microwave-Hydrothermal Synthesis

摘要

Sodium-potassium-niobate (K_xNa_(1-x)NbO_3) lead-free piezoelectric powders were synthesized using the microwave-hydrothermal method. The effect of different parameters such as temperature, reaction time, and alkalinity of the precursor on the crystalline size and morphology of K_xNa_(1-x)NbO_3 was investigated. It has been shown that the K_xNa_(1_x)NbO_3 phase forms at 150°C, and K_(o.5)Na_(0.5)NbO_3 (KNN) powders with perfect crystallinity and a uniform size have been prepared at 160°C for 7h. Transmission electron microscopy images indicate that the KNN powders are single crystalline. Because of microwave enhancement, the K_xNa_(1-x)NbO_3 synthesis has been speeded up, resulting in the crystallization of the K_xNa_(i-x)NbO_3 phase at a temperature as low as 150°C.