Improvement in Electrical Properties of (Bi<inf>0.5</inf>Na<inf>0.5</inf>)TiO<inf>3</inf> (BNT) Ceramics Using the Seed-Induced Method

Abstract

(Bi0.5Na0.5)TiO3 (BNT) lead-free ceramics were prepared by the seed-induced technique using different particle sizes of BaTiO3 (BT) powder as seeds. The BT seeds was synthesized by the molten-salt method and then calcined at different temperatures of 750 (750BTs), 800 (800BTs) and 850 °C (850BTs). The pure perovskite seeds (5 mol%) were mixed with the starting materials of the BNT system for conventional mixed oxide method. After that, the mixture was calcined and sintered at 900 °C for 2 h and 1100 °C for 2 h, respectively. From results it was found that the particle size of BT seed increased with calcine temperature increase from 750 to 850 C. The samples of non-BT seed (S0) and BT seed-added (S1, S2 and S3) showed pure perovskite phase. Average density values were in the range of 5.53-5.77 g/cm3. Dielectric constant (εr) measured at room temperature (at 1 kHz) was in the range of 732.04-788.59. The dielectric loss (tanδ), remnant polarization (Pr) and coercive field (Ec) values decreased with the addition of BT seed. The highest piezoelectric coefficient (d33) ∼156 pC/N was obtained for the sample of 850BTs (S3).