Chemical Synthesis of K_0.5Na_0.5NbO₃ Ceramics and Their Electrical Properties

Abstract

Powders of K_0.5Na_0.5NbO₃ (KNN) were prepared by the Polymerized Complex Method (PC method), based on the Pechini-type reaction route. The crystallization process of KNN during the calcination of an amorphous precursor was observed, using TG-DSC analysis and X-ray powder diffraction. After calcination the powders were ball milled, pressed into pellets, and sintered at 1100°C, which is lower than the sintered temperature of the conventional solid-state method. Using this procedure, we achieved relatively high-density and very homogeneous KNN ceramics. The electric properties of the ceramics were investigated. The results showed that these values are superior to those of sintered KNN ceramic counterparts made by the conventional solid-state method.

Keywords:

• Chemical synthesis
• Dielectric properties
• Dielectric loss
• Electrical properties
• Lead-free piezoelectric ceramics
• Microstructure
• (K_0.5Na_0.5)NbO₃
• Permittivity
• Phase transition
• Piezoelectric coefficient
• Piezoelectric properties
• Planar coupling coefficient
• Polymerized complex method
• P–E hysteresis loops

ACKNOWLEDGMENTS

This work is supported by the National Natural Science Fundation of China (grant No. 50672056, 50432010).