High Electric‐Induced Strain and Temperature‐Dependent Piezoelectric Properties of 0.75BF–0.25BZT Lead‐Free Ceramics

Abstract

0.75BiFeO 3 -0.25Ba(Zr x Ti 1 -x ) + 0.6 wt% MnO 2 (0.75BF-0.25BZT) ceramics with Mn addition were prepared by the solid-state reaction method. The high-field strain and high-temperature piezoelectric properties of 0.75BF-0.25BZT ceramics were studied. Introduction of Zr in the solid solutions decreased the Curie temperature slightly, and improved the dielectric and piezoelectric properties obviously. The piezoelectric properties of 0.75BZT-0.25BT ceramics reached the maximum at Zr content of 10 mol%. The Curie temperature T c , dielectric constant e and loss tand (1 kHz), piezoelectric constant d 33 , and planner electromechanical coupling factor k p of 0.75BF-0.25BZT ceramics with 10 mol% Zr were 456°C, 650, 5%, 138 pC/N, and 0.30, respectively. The high-field bipolar and unipolar strain under an electric field of 100 kV/cm reached up to 0.55% and 0.265%, respectively, which were comparable to those of BiScO 3 -PbTiO 3 and "soft" PZT-based ceramics. The typical "butterfly"-shaped bipolar strain and frequency-dependent peak-to-peak strain indicated that the large high-field-induced strain may be due to non-180°domain switching. Rayleigh analysis reflected that the improved piezoelectric properties resulted from the enhanced extrinsic contribution by Zr doping. The unipolar strain of 0.75BF-0.25BZT ceramics with 10 mol% Zr was almost linear from RT to 200°C. These results indicated that 0.75BF-0.25BZT ceramics were promising candidates for high-temperature and lead-free piezoelectric actuators.

The effect of cooling rate on structural and electrical properties of multiferroic BLF‐PT ceramics

“…where ε int, ε*, ε′′, and E 0 represent the intrinsic contribution to dielectric constant, complex permittivity, imaginary part permittivity and the applied electric field, respectively . The E 0 should be small enough, less than half of E c , not being able to change the domain size and the density of domain in poled ceramics.…”

“…where e int, e*, e 00 , and E 0 represent the intrinsic contribution to dielectric constant, complex permittivity, imaginary part permittivity and the applied electric field, respectively. [25][26][27] The E 0 should be small enough, less than half of E c , not being able to change the domain size and the density of domain in poled ceramics. Compared with specimens cooled in furnace, BLF-PT ceramics cooled in BW and NaCl solution exhibit the larger e 0 under the same E 0 .…”

Low‐temperature sintering of BF‐PT‐BZ ternary solid solutions with enhanced piezoelectric properties

“…The field-induced strains of ferroelectric ceramics consist of the contribution of extrinsic irreversible non-180 o domains switch, domain wall motion, as well as the intrinsic lattice distortion. 36,37 The extrinsic contribution can be represented by S neg , which was determined by the maximum negative strain of bipolar S-E loops. The proportion of the extrinsic contribution to the maximum strain S in unipolar curves could be expressed as S neg /S.…”

Excellent thermal stability and aging behaviors in BiFeO3‐BaTiO3 piezoelectric ceramics with rhombohedral phase

“…[6][7][8] Chemical modifications (Co, Zr, Al, Ga, Mg 1/2 Ti 1/2 , Ni 1/2 Ti 1/2 , and Zn 1/2 Ti 1/2 ) and quenching treatment are also performed on BF-BT solid solution, with improved piezoelectric properties up to 120-200 pC/N for the compositions with R-PC boundary. [12][13][14][15][16][17][18][19][20][21] Recently, Lee et al reported a high piezoelectric coefficient of 402 pC/N at the MPB (Coexistence of Rhombohedral and Tetragonal phases) compositions of Ga-doped BiFeO 3 -BaTiO 3 ceramics with water-quenched treatment. 2 In ferroelectric materials, the domain forms when they transform from paraelectric to ferroelectric phase at Curie temperature, which is the region with the same polarization orientation.…”