Crystallographic evolution, dielectric, and piezoelectric properties of Bi4Ti3O12:W/Cr ceramics

Abstract

W/Cr codoped Bi4Ti3O12 ceramics, Bi 4Ti3-xWxO12+x+0.2 wt%Cr 2O3 (BITWC, x=0-0.15), were prepared using a solid-state reaction method. The crystallographic evolution and phase analysis were distinctly determined focusing on the X-ray diffraction peak changes in (020)/(200) and (220)/(1115) diffraction planes, by which the lattice parameters, a, b, and c can be refined. The thermal variations of permittivity, dielectric loss (tan δ), impedance, and electrical conductivity properties were characterized. A decrease in the values of Curie temperature from 675° to 640°C and an increase in the values of the dielectric constant due to an increase of W6+/Cr3+ content were observed. The highest piezoelectric constant, d33 of 22 pC/N, was achieved with the composition of Bi4Ti2.975W0.025O 12.025+0.2 wt% Cr2O3. Also, this composition had a lower electrical conductivity than the other investigated compositions. © 2010 The American Ceramic Society.