Effects of La-doping on microstructure, dielectric and piezoelectric properties of Ba0.85Ca0.15Ti0.90Zr0.10O3 lead-free ceramics

Pb-free ceramics Ba 0.85 Ca 0.15 Ti 0.90 Zr 0.10 O 3 inspired by the excellent piezoelectricity of morphotropic phase boundary deriving from a tricritical point have been prepared by a solid state reaction route and the effects of grain size and room-temperature phases of the ceramics have been studied in detail. When sintering temperature rises from 1320 to 1560°C with controlling the dwell time for 2 h, the ceramic sintered at 1480°C possesses the optimum piezoelectricity. We choose 1360 and 1480°C as two distinctive sintering temperatures to further study the effect of dwell time on the electrical properties of the ceramics. The results show that the improved piezoelectric behavior (d 33 * 416 pC/N and k p * 55.8 %) is demonstrated for the Ba 0.85 Ca 0.15 Ti 0.90 Zr 0.10 O 3 ceramic at an optimal sintering temperature of 1480°C and dwell time of 2 h, which is attributed to the largest grain size together with more noticeable rhombohedral-tetragonal phase transition near room-temperature.

Section: Introductionmentioning

confidence: 99%

Correlation of grain size, phase transition and piezoelectric properties in Ba0.85Ca0.15Ti0.90Zr0.10O3 ceramics

Sun

Zheng

Wan

et al. 2015

“…Lead-free materials have received considerable attention in recent decades due to interest in the reduction of environmental impact by using appropriate materials to replace harmful ones [1]. For this purpose, bismuth-based materials have been considered.…”

Section: Introductionmentioning

confidence: 99%

Correlation between lattice distortion and magnetic and electrical properties of Fe-doped Bi4Ti3O12 ceramics

Liu

2015

Aurivillius phase Bi 4 Ti 3 O 12 -xFe 2 O 3 (BIT-xFe, x = 0-0.08) ceramics were prepared by conventional solid-state method. The crystallographic evolution was determined via the X-ray diffraction patterns, by which the lattice parameters, a, b and c were also calculated. It was found that the increasing content of Fe 2 O 3 reduced the lattice distortion of BIT-based ceramics, which led to a phase transition from orthorhombic to tetragonal. Ferroelectricity and magnetization data showed that BIT-xFe ceramics possess expected ferroelectric and ferromagnetic behaviors. Besides, the grain size decreased as structure changed from rod-like to sphere with increasing x, which can be observed in the SEM. The dielectric constant can be analyzed by a ''brick-wall'' model, the dielectric loss and dc conductivity had a tendency to decrease with increasing x.

“…Similar phenomenon has been observed in the La 3? -doped BaTiO 3 -based ceramics [18]. The observed k p decreases from 40.9 to 23.9 % with x increasing from 0 to 0.03.…”

Section: Resultsmentioning

confidence: 88%

“…. This inhibition of grain [16][17][18]. For the KNLNST-Dy-x ceramics, A-site vacancies of metal ions caused by Dy 3?…”

Section: Introductionmentioning

confidence: 99%

Phase transition, electrical and luminescent properties of Dy-doped K0.5Na0.5NbO3-based lead-free ceramics

Wen

Zhou

Zou

et al. 2015

Self Cite

Dy-modified K 0.5 Na 0.5 NbO 3 -based lead-free piezoelectric ceramics of (K 0.48 Na 0.48 Li 0.04 ) 1-x Dy x/3 (Nb 0.90 Ta 0.04 Sb 0.06 )O 3 lead-free piezoelectric ceramics were prepared by a conventional ceramics technique and the effects of Dy 3? doping on the crystal structure, microstructure, dielectric, piezoelectric and luminescent properties of the ceramics were investigated. The ceramics with low Dy levels (x B 0.015) show a pure perovskite structure, while a small amount of secondary phase DyNbO 4 can be detected in the ceramics with x C 0.02. The increase in the level of Dy 3? doping leads to the shift of crystal structure of the ceramics from the coexistence of orthorhombic-tetragonal phases to pseudo-cubic phase. The addition of Dy 3? inhibits the grain growth of the ceramics and induces the diffusive phase transition in the ceramics with high levels of Dy 3? ions. The piezoelectric constant d 33 of the ceramics decreases from 198 to 52 pC/ N with x increasing from 0 to 0.03 because of the shift of the crystal structure of the ceramics from the coexistence of orthorhombic-tetragonal phase to pseudo-cubic phase. The Dy-doped ceramics excited at 453 nm have excellent luminescent properties. Two strong emission spectral bands centered at 476 and 573 nm are observed, corresponding to the transition of the 4 F 9/2 ? 6 H 15/2 and 4 F 9/2 ? 6 H 13/2 levels of Dy 3? , respectively. Our study shows that the ceramic with x = 0.015 possesses simultaneously strong ferroelectricity, good piezoelectricity and excellent luminescence, suggesting that the Dy-doped ceramics may have potential application in multifunctional devices.