Preparation and characterization of textured Bi_0.5(Na_0.8 K_0.2)_0.5TiO₃ ceramics by reactive templated grain growth

Bi_0.5(Na_0.8 K_0.2)_0.5TiO₃ (abbreviated as BNKT) piezoelectric ceramics with extensive <001> texture were prepared by the reactive templated grain growth (RTGG), using plate-like Bi₄Ti₃O₁₂ (BiT) particles as the templates. Through the analysis of X-ray diffraction pattern of the obtained materials, extensive crystallographic texture was evaluated with a relatively high Lotgering factor (f ≥ 0.9), and the incorporated (Bi_0.5 K_0.5)TiO₃ diffused into the (Bi_0.5Na_0.5)TiO₃ lattice to form a single solid solution. The scanning electron microscopy showed that the in-situ reaction started at the vicinity of BiT surface and proceeded with heat treatment time toward the inner part of the BiT. The high textured BNKT piezoelectric ceramics demonstrated good piezoelectric performance without decreasing the depolarization temperature when they were sintered at 1200 °C for 10 h.