Enhanced electrical properties of (Li,Ce) co-doped Sr(Na0.5Bi0.5)Bi4Ti5O18 high temperature piezoceramics
Abstract
Lead-free piezoelectric ceramics with the formula of Sr1−x(Li,Ce)x/2(Na0.5Bi0.5)Bi4Ti5O18 (LCSNBT-x, x = 0.0, 0.1, 0.2, 0.3, 0.4), were prepared by a conventional solid-state reaction method. X-ray diffraction analysis suggested that the substitution led to the formation of a layered perovskite structure. Plate-like morphologies were clearly observed for all the samples. The activation energy values of the ionic conductivity suggested defects were related to oxygen vacancies. The excellent electrical properties (e.g., d33 ∼ 24 pC N−1, 2Pr ∼ 15 μC cm−2 and Tc ∼ 571 °C) are simultaneously obtained in the ceramics with x = 0.2. Additionally, thermal annealing studies indicated that the piezoelectric constant (d33) of the LCSNBT-0.2 ceramic remains almost unchanged (22 pC N−1, only decreased by 8%) at temperatures below 400 °C, demonstrating that the ceramic is a promising candidate for high-temperature applications.