Effect of composition on electrical properties of lead-free Bi<inf>0.5</inf>(Na<inf>0.80</inf>K<inf>0.20</inf>)<inf>0.5</inf>TiO<inf>3</inf>-(Ba<inf>0.98</inf>Nd<inf>0.02</inf>)TiO<inf>3</inf>piezoelectric ceramics

Abstract

Lead-free piezoelectric ceramics with the composition of (1-x)Bi0.5(Na0.80K0.20)0.5TiO3-x(Ba0.98Nd0.02)TiO3or (1-x) BNKT-xBNdT (with x = 0-0.20 mol fraction) have been synthesized by a conventional mixed-oxide method. The compositional dependence of phase structure and electrical properties of the ceramics were systemically studied. The optimum sintering temperature of all BNKT-BNdT ceramics was found to be 1125°C. X-ray diffraction pattern suggested that BNdT effectively diffused into BNKT lattice during sintering to form a solid solution with a perovskite structure. Scanning electron micrographs showed a slight reduction of grain size when BNdT was added. It was found that BNKT-0.10BNdT ceramic exhibited optimum electrical properties (εr= 1716, tanδ = 0.0701, Tc= 327°C, and d33= 211 pC/N), suggesting that this composition has a potential to be one of a promising lead-free piezoelectric candidate for dielectric and piezoelectric applications. © 2013 AIP Publishing LLC.