Lead-Free KNbO 3 :xZnO Composite Ceramics.

It is a tough issue to develop dense and water resistant KNbO3 ceramics due to high evaporation and hygroscopicity of K2 O. Here, KNbO3 :xZnO composite ceramics were used to successfully solve this problem, where ZnO particles were randomly distributed into a KNbO3 matrix. The addition of ZnO hardly affects the phase structure of KNbO3 , and moreover, the enhancement of electrical properties, thermal stability, and aging characteristics was observed in KNbO3 :xZnO composite ceramics. The composites possessed the maximum d33 of 120 ± 5 pC/N, which is superior to that of pure KNbO3 (d33 = 80 pC/N). More importantly, a strong water resistance and an aging-free characteristic were observed in KNbO3 :0.4ZnO. This is the first time for KNbO3 ceramics to simultaneously improve electrical properties and resolve the water-absorbing properties. We believe that these composite ceramics are promising for practical applications.