The roles of Sn4+ in affecting performance of Potassium Sodium Niobate ceramics

Abstract

In the KNN ceramics system, the contradictory relationship between piezoelectricity and phase transition temperature has received extensive attention from researchers. Herein, by studying the doping mechanism of Sn4+ in 0.957(K0.48Na0.52)NbO3-0.003BiCoO3-0.04(Bi0.5K0.5)Zr1-xSnxO3 (KNN-BC-BKZ1-xSx), the coexistent of excellent piezoelectricity and ideal Curie temperature is realized in KNN ceramics. The addition of Sn4+ keeps R-O-T coexistence system in KNN-BC-BKZ1-xSx ceramics, thereby maintaining the low energy barrier of domain rotation. Further investigation has shown that the substitution of Sn4+ can promote grain growth and increase the density of ceramics. In addition, the optimal comprehensive properties (d33 = 391 pC/N, kp = 0.518, TC = 332 °C, d33* = 512 pm/V) are simultaneously obtained at x = 0.15. Particularly, due to growth of grain size, excellent temperature stability is obtained within a broad temperature range. The discovery of Sn4+ doping is useful to the development of KNN-based materials with both piezoelectric electrical properties and Curie temperature as it provides a new idea for enhancing performances of ceramics.