Effects of different ratios of K/Na on the structure and properties of (KxNa1−x)NbO3 ceramics

K_0.5Na_0.5NbO₃ (KNN) ceramics is considered as one of the most promising candidates for lead free piezoelectric ceramics, because of its high Curie temperature and good electrical properties. However, it is well known that dense and well-sintered KNN ceramics are very difficult to obtain because of the high volatility of alkali elements at high temperatures. According to some references, the molar ratio of K/Na has large influence on electrical properties of KNN-based ceramics. In this article, the effects of different ratios of potassium to sodium and sintering temperatures on phase structure, microstructure and electrical properties of KNN-based ceramics were investigated. Result showed that the KNN ceramic with x=0.5 sintered at 1080 °C existed the primary phase perovskite structure and showed optimized properties.