In this paper, (K0.5Na0.5)NbO3 (KNN) ceramics are prepared by a simple and cost- effective reactive sintering method. Starting materials of K2CO3, Na2CO3 and Nb2O5 are mixed by ball-milling, pressed into pellets and sintered at 1080 oC, 1100 oC and 1120 oC for between 0.25-3 hours. The Archimedes density of samples sintered at 1120 oC reached 91% of the theoretical density after 30 min sintering time. All samples show a single phase perovskite structure after sintering. Samples sintered at 1080 oC have a fine-grained microstructure whereas samples sintered at 1100 oC and 1120 oC show abnormal grain growth. Samples sintered at 1120 oC for 1 hour show dielectric, ferroelectric and piezoelectric properties comparable to those of conventionally-sintered KNN. A conduction mechanism with activation energy of 0.62 eV for the high leakage in the KNN system was revealed by impedance spectroscopy.

Keywords: Lead-free piezoelectric, Potassium sodium niobate, Reactive sintering, Microstructure, Dielectric properties, Ferroelectric properties, Piezoelectric properties, Impedance spectroscopy.