Effect of KNbO₃ addition on diffuse phase transition and dielectric properties of Bi_0.5Na_0.5TiO₃ ceramics

ABSTRACT

Lead-free (1-x)Bi_0.5Na_0.5TiO₃ – xKNbO₃ (BNT-KN) ceramics where x = 0.00, 0.05, 0.10 and 0.15 were carried out by the modified two-step mixed oxide method. The effects of KNbO₃ on phase transition and dielectric properties were systematically investigated. The dielectric property investigation indicated that the degree of the diffuse phase transition behavior increased with KNbO₃ addition. Phase transition of rhombohedral to pseudocubic structure was dependent on the amount of KNbO₃ contained. The dielectric constant of the KNbO₃ added Bi_0.5Na_0.5TiO₃ ceramic was enhanced by KNbO₃ addition. The maximum dielectric constant is obtained at the composition of x = 0.05. KN addition could enhance the piezoelectric response. The d₃₃ of x = 0.05 sample reached as high as 130 pC/N.

KEYWORDS:

• Phase transition
• lead-free ceramic
• dielectric properties

Acknowledgments

The authors would like to thank the Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan and the Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi.