Tailoring Of Ferroelectrics In (Na2o, K2o)-Nb2o5-Sio2 Glass-Ceramics Via Control The Crystallization Kinetics

Crystallization kinetics of (Na2O, K2O)-Nb2O5-SiO2 glass-ceramics were systematically studied in this work and the growth index of all the samples were larger than 3, demonstrating a mechanism of volume crystallization for glass-ceramics. KNbSi2O7 phase was precipitated when the crystallization temperature was selected at exothermic peak2. With the addition of Bi2O3, grain size increased from 50 nm to 500 nm approximately because of the variation of crystallization kinetics. With the increasing grain size, both the I-E curves and P-E loops showed an enhancement of ferroelectricity. Proved by PFM, polarization structure appeared at 10 kV/cm. Complex impedance was measured to study the conduction mechanism of glass-ceramics. With the introduction of Bi2O3, breakdown strength increased because of low conductivity. However, a large conductivity decreased breakdown strength when x = 10. Charge-discharge test was used to calculate the energy density, which was lower than the theoretical energy calculated by P-E loops, and the difference was high when slow polarization dominates in discharge.