High Strain and Piezoelectric Characteristics of Textured Bi0.5(Na0.85K0.15)0.5TiO3 Ceramics

The anisotropy of polarization and strain behavior in textured Bi_0.5(Na_0.85K_0.15)_0.5TiO₃ ceramics are investigated for lead-free piezoelectric ceramics actuators. The textured Bi_0.5(Na_0.85K_0.15)_0.5TiO₃ ceramics are fabricated by reactive templated grain growth (RTGG) using plate-like Bi₄Ti₃O₁₂ particles. RTGG[//] (sliced parallel to the casting direction) and RTGG[square] (sliced perpendicularly to the casting direction) specimens show preferred orientation to <001>_pc and <110>_pc, respectively. RTGG[//] specimen has relatively high piezoelectric coefficient of (d₃₃) ~335 pm/V and electric field induced strain levels of 0.067% at 20 kV/cm. This values were 86% higher than those of RTGG[ square] specimen. <001>_pc textured polycrystalline BNKT ceramics, prepared by RTGG, are a strong candidate for lead-free piezoelectric materials of actuators.