Microstructure and piezoelectric properties of Bi0.5(Na0.82K0.18)0.5TiO3−NaSbO3 ceramics

Lead-free piezoelectric ceramics (1−x)Bi0.5(Na0.82K0.18)0.5TiO3−xNaSbO3 have been prepared by a conventional ceramics technique, and their microstructure and electrical properties have been investigated. The addition of NaSbO3 has no remarkable effect on the crystal structure within the studied doping content; however, an obvious change in microstructure took place. With increase in NaSbO3 content, the temperature from a ferroelectric to antiferroelectric phase transition increases, and the temperature for a transition from antiferroelectric phases to paraelectric phases changes insignificantly. Simultaneously, the temperature range between the rhombohedral phase transition point and the Curie temperature point becomes smaller. The piezoelectric properties significantly increase with increase in NaSbO3 content and the piezoelectric constant and electromechanical coupling factor attain maximum values of d33=160 pC/N and kp=0.333 at x=0.01. The results indicate that (1−x)Bi0.5(Na0.82K0.18)0.5TiO3−xNaSbO3 ceramic is a promising lead-free piezoelectric candidate material.

► The effect of NaSbO3 on microstructure and electrical properties of BNKT ceramics has been investigated.
► The piezoelectric properties significantly increase with increasing NaSbO3 content.
► The piezoelectric constant and electromechanical coupling factor attain maximum values of d33=160 pC/N and kp=0.333 at x=0.01.