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

Abstract

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 ∼10 μm in the ceramic at x = 0.05. BTWC ceramics showed a continuous decrease in Tc and a gradual increase in εr with the increasing W doping content. While the hard-doping of Cr2O3 decreased, the TKε and tan δ of ceramics available. All the ceramics keep the nature of first-order transition and displacive ferroelectrics. The d33 and kp of BTWC ceramics were remarkably improved by the soft-doping of W6+. Excellent electrical properties (e.g., Tc = 638 °C, εr = 146, tan δ = 0.56%, TKε (500 °C) = 1.30 × 10−3/ °C, τ (500 °C) = 4.08 × 10−5 s, d33 = 28 pC/N, and kp = 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.