Effect of sintering temperature on electrical properties of Na0.5K0.5NbO3 lead-free piezoelectric ceramics prepared by normal sintering

The effects of sintering temperature on microstructure, density and electrical properties of Na0.5K0.5NbO3 prepared by normal sintering at 1020-1100 degrees C were investigated. All the Na0.5K0.5NbO3 ceramics showed an orthorhombic structure similar to that of KNbO3 ceramics, while raising sintering temperature resulted in the shifting of diffraction peaks to a lower value and the formation of a second phase due to the excess volatilization of Na. Both density and d(33) of the sintered samples increase with increasing sintering temperature. The density of the sample sintered at 1080 degrees C reaches a maximum value (4.22 g/cm(3), 92% of the theoretical density). The sample sintered at 1060 degrees C showed a maximum d(33) value of about 122 pC/N and the highest T-c of about 409 degrees C, and the corresponding E-c and P-r were about 13 kV/cm and 15 mu C/cm(2), respectively.