Microstructure and Ferroelectric Properties of (Na,K)(Nb,Sb)O₃ Ceramics Substituted with LiTaO₃

Abstract

In this study, in order to develop lead-free composition ceramics for piezoelectric actuator, (Na,K)(Nb,Sb)O₃ ceramics modified with LiTaO₃ were prepared by a conventional mixed oxide method. The influences of LiTaO₃ on the microstructure, dielectric, ferroelectric, and piezoelectric properties were investigated. All the specimens showed a pure perovskite phase and no secondary phase could be confirmed from the XRD patterns. The SEM images indicate that the grain size increased with increasing the content of LiTaO₃-substitution. Excellent physical properties of piezoelectric constant (d₃₃) = 280 pC/N, electromechanical coupling factor (k_p) = 0.534, dielectric constant (ϵ_r) = 980, and density (ρ) = 4.50 g/cm³ were obtained from the composition ceramic with x (LiTaO₃) = 0.0375. These results indicate that the composition ceramic is a promising lead-free piezoelectric material for actuator applications.

Keywords:

• Lead-free ceramic
• LiTaO₃
• NKN
• Piezoelectric constant (d₃₃)

Acknowledgements

This work was supported by the Power Generation & Electricity Delivery of the Korean Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean government Ministry of Knowledge Economy (No. 2010T100100282).