Enhanced piezoelectric properties of 〈110〉 grain-oriented 0.50(Bi_0.5Na_0.5)TiO₃–0.50BaTiO₃ ceramics by domain engineering above Curie temperature

Abstract

Lead-free 〈110〉 grain-oriented tetragonal 0.50BNT–0.50BT ceramics were fabricated by the reactive-templated grain growth (RTGG) method with plate-like H_1.08Ti_1.73O₄·nH₂O (HTO) templates. A high relative density of 97 % was obtained by sintering at 1200 °C for 2 h. An orientation degree (F₁₁₀) of 63 % was obtained by the Lotgering method. Domain engineering treatment above their Cuire temperature (T_c) was conducted under optimized alternating current (AC) poling and direct current (DC) poling conditions. With optimized conditions, the piezoelectric coefficient d₃₃ values measured by a d₃₃ meter were 82 pC/N for AC poling and 58 pC/N for DC poling, respectively. The nearly 40 % increase in d₃₃ could be attributed to the fine domain structures induced by the optimized AC conditions.