Microstructures, dielectric, and piezoelectric properties of W/Cr co-doped Bi4Ti3O12 ceramics

W/Cr co-doped Bi4Ti3O12 (BTWC) ceramics {Bi4Ti3-xWxO12+x + 0.2 wt. % Cr2O3 (x = 0-0.1)} with a high piezoelectricity were prepared by a conventional ceramic process, and effects of W/Cr dopant on the microstructures, dielectric, and piezoelectric properties of ceramics were explored. It is found that W6+ modified the grain morphology and size of ceramics, promoting the forming of the regular schistose grains with a size of similar to 10 mu m in the ceramic at x = 0.05. BTWC ceramics showed a continuous decrease in T-c and a gradual increase in epsilon(r) with the increasing W doping content. While the hard-doping of Cr2O3 decreased, the TK epsilon and tan delta of ceramics available. All the ceramics keep the nature of first-order transition and displacive ferroelectrics. The d(33) and k(p) of BTWC ceramics were remarkably improved by the soft-doping of W6+. Excellent electrical properties (e.g., T-c = 638 degrees C, epsilon(r) = 146, tan delta = 0.56%, TK epsilon (500 degrees C) = 1.30 x 10(-3)/degrees C, tau (500 degrees C) = 4.08 x 10(-5) s, d(33) = 28 pC/N, and k(p) = 6.17%) have been achieved in Bi4Ti2.95W0.05O12.05 + 0.2 wt.% Cr2O3 ceramic. Such a material can be a promising candidate for high-temperature piezoelectric applications. (C) 2014 AIP Publishing LLC.