Effect of Sintering Temperature on Electrical Properties of Na_(0.5)K_(0.5)NbO_3 Lead-Free Piezoelectric Ceramics Prepared by Normal Sintering

摘要

The effects of sintering temperature on microstructure, density and electrical properties of Na_(0.5)K_(0.5)NbO_3 prepared by normal sintering at 1020-1100 deg C were investigated. All the Na_(0.5)K_(0.5)NbO_3 ceramics showed an orthorhombic structure similar to that of KNbO_3 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 deg C reaches a maximum value (4.22 g/cm~3, 92 percent of the theoretical density). The sample sintered at 1060 deg C showed a maximum d_(33) value of about 122 pC/N and the highest T_c of about 409 deg C, and the corresponding E_c and P_r were about 13 kV/cm and 15 mu C/cm~2, respectively.