Polymorphic structure evolution and large piezoelectric response of lead-free (Ba,Ca)(Zr,Ti)O3 ceramics

Abstract

The polymorphic structure evolution of (Ba,Ca)(Zr,Ti)O3 piezoelectric ceramics was investigated by analysis of the in situ X-ray diffraction and dielectric spectra. The results indicated that a confined orthorhombic (O) phase region induced by the approach of the rhombohedral (R) and tetragonal (T) phases existed in an extremely narrow temperature range of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 composition. The electric properties near the O–T phase boundaries of (Ba0.95Ca0.05)(Zr0.05Ti0.95)O3 and (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 were compared. The results suggested that the confined O phase region is an important factor that contributes to the extremely large piezoelectric response.

Electrical properties and low temperature sintering of BiAlO3 doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoelectric ceramics

“…The tetragonal-cubic (at T c ), orthorhombic-tetragonal (at T O-T ) phase transition peaks and the dielectric loss peak (T d ) can be seen in Fig. 4a [7]. There is a little shift of T O-T peak towards lower temperature with increasing BAO content.…”

“…Recently, a significant improvement in Ba(Ti 0.8 Zr 0.2 )O 3 -(Ba 0.7 Ca 0.3 )TiO 3 ceramics sintered at 1450-1500°C has been achieved by Ren et al [6]. The emergence of this large piezoelectric constant (d 33 = 620 pC/N) is highly promising for the practical applications [6,7]. Nevertheless, the sintering temperature for full densification of Ba(Ti 0.8 Zr 0.2 )O 3 -(Ba 0.7 Ca 0.3 )TiO 3 ceramics is above 1450°C, which is considerably high for the practical applications.…”

Phase transition and improved electrical performance of Ba0.85Ca0.15Zr0.1Ti0.9O3–Ca0.28Ba0.72Nb2O6 ceramics with high Curie temperature

“…Ba(Zr 0.2 Ti 0.8 )-x(Ba 0.7 Ca 0.3 )TiO 3 (BZT-xBCT)-based ceramics have attracted much attention recently because of their superior piezoelectric performance (~620 pC/N) compared with lead-based materials [1][2][3]. These ceramics are regarded as promising candidates for novel next generation piezoelectric devices.…”

Phase transitions and phase diagram of Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 Pb-free system by anelastic measurement

“…9,11,32,33 The dynamic response to an AC electric field gives the real part ( 0 ) and the imaginary part ( 00 ) of the permittivity and their ratio is the dielectric loss, tan d ¼ 0 00 . However, because there is strong coupling between lattice distortions (strain) and the ferroelectric order parameter (polarization), it is inevitable that there will be changes in elastic and anelastic properties associated with the discrete phase transitions in the BZT-xBCT lead-free system.…”