Lead-Free KNbO₃:xZnO Composite Ceramics

It is a tough issue to develop dense and water resistant KNbO₃ ceramics due to high evaporation and hygroscopicity of K₂O. 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.