Piezoelectric Properties of Lead-Free (Bi_1/2Na_1/2)TiO₃ Doped PZT Ceramics

Abstract

Fabrication conditions, piezoelectrical and mechanical properties of lead-free (Bi_1/2Na_1/2)TiO₃ (BNT) doped PZT ceramics were investigated. For BNT as additives, decarbon dioxide of starting materials terminated to 700°C. Crystallization of BNT was induced above 600°C. The crystal phase of the sintered BNT ceramics was rhombohedral (a=3.885Å, a=90.003°). The secondary phase of Bi₂TiO₇ was formed by adding excess Na₂O. Additon of excess Na₂O promoted the sintering of BNT. For BNT doped PZT, the electromechanical coupling factor (kp) value was maintained at 60-70% of PZT with 0.5 and 1.0% BNT. The four point bending strength of BNT doped PZT specimens with 0.5 and 1.0 wt%BNT addition sintered at 1150°C was increased. The maximum value of Weibull modulus was 9.5.