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[(Ba0.85Ca0.15)1-xDyx](Zr0.1Ti0.9)O3 (x mol% Dy-BCZT, x = 0.05, 0.2, 0.5, 1 and 3 mol%) multifunctional lead-free ceramics were prepared by traditional solid-state reaction method, where the influence of Dy doping amount and sintering condition was investigated. All sintered x mol% Dy-BCZT ceramics exhibit pure perovskite structure, large density, and high resistivity, which are affected greatly by Dy doping amount and sintering temperature. The phase structure changes from mainly tetragonal phase to pseudo-cubic phase with the increase of Dy doping amount, and presents irregular change on sintering temperature. Most samples have excellent dielectric, ferroelectric and stain, piezoelectric and fluorescent properties, which can be improved by changing Dy doping amount and tailoring sintering condition. Maximum piezoelectric-fluorescent coupling effect is obtained by selecting composition, optimizing Dy doping amount, and tailoring sintering condition due to morphotropic phase boundary effect and concentration quenching effect, which provides broad application prospect in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

0.55 Bi(Ni0.5Ti0.5)O3–0.05BiFeO3–0.4PbTiO3 ((0.55BNT–0.05BF–0.4PT)) ceramics were prepared by low-temperature solid-phase sintering method due to adding sintering additives. The 800 °C calcined powders present relatively pure perovskite structure. The 990 °C–1030 °C sintered ceramics exhibit pure perovskite structure, and the density is increased significantly as compared with the undoped ones due to the addition of 0.5 wt% LiBO2. The "0.55BNT–0.05BF–0.4PT" samples sintered at 1010 °C have large density, compact microstructural morphology, high Curie temperature and excellent electrical properties. The ceramics show apparent relaxor ferroelectric behavior and dielectric relaxation characteristic. Grains conduction contributes mainly to the high-temperature conduction, which can be attributed to the migration of oxygen vacancies produced due to the evaporation of ions during sintering. [ABSTRACT FROM AUTHOR]

xPb(Mg1/3Nb2/3)O3-yPbZrO3-(1-x-y)PbTiO3(PMN-PZ-PT) ferroelectric ceramics were prepared by the conventional ceramic processing via a B-site oxide mixing route. Complete solid solutions can be formed for PMN-PZ-PT in the whole composition range studied, which exhibits pure tetragonal, morphotropic phase boundary (MPB) or rhombohedral perovskite structure depending on compositions. Enhanced structure and electrical performance detected by XRD measurement, and dielectric, ferroelectric and piezoelectric properties characterization confirm the MPB effect. Such phenomena correspond well with the composition-induced successively structural change from rhombohedral, across MPB, and to tetragonal perovskite structure with the increase of the PbTiO3content. The preliminary composition phase diagram of the PMN-PZ-PT system is determined by XRD measurement combining with electrical properties characterization. The mechanisms of the structure and electrical properties enhancement are related to easy paths with flattened free energy induced by polarization rotation and polarization extension. [ABSTRACT FROM AUTHOR]

0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3(0.69PMN-0.31PT) ceramics were prepared by the solid-state reaction method via the columbite precursor route, which exhibit phase-pure perovskite structure with the morphotropic phase boundary (MPB) composition and excellent electrical properties, and are appropriate for further research. Dielectric aging behavior of the 0.69PMN-0.31PT ceramics exhibits a linear decrease dependence on the logarithm of time, proving partly its relaxor ferroelectric characteristic and correlates with microcompositional inhomogeneity. The electrical properties of the 0.69PMN-0.31PT ceramics decrease greatly above the depolarization temperature, being 120°C, whereas they exhibit excellent time stabilization. Mechanical properties of the 0.69PMN-0.31PT ceramics are improved apparently after coating Ag electrode and poling, which relate to the contributions of electrode status and domain switching. The major failure mechanism is transgranular fracture in the compression fracture samples and intergranular fracture in the bending fracture samples, respectively, determined by SEM observation. [ABSTRACT FROM PUBLISHER]

The 0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3(0.69PMN-0.31PT) ceramics were prepared by a partial oxalate route via the columbite precursor method, a modified columbite precursor method and the B-site oxide mixing route. X-ray diffraction (XRD) measurement confirmed that pure-phase perovskite 0.69PMN-0.31PT ceramics were prepared by the modified columbite precursor method. All the sintered 0.69PMN-0.31PT ceramics exhibit large relative density, and rather homogenous and densified microstructure morphology, in which the 0.69PMN-0.31PT ceramics prepared by the modified columbite precursor method exhibit large bulk density, being 7.9015 g/cm3, which reaches 96.74% of the theoretical density. The largest value of dielectric constant maximum (ϵm) appears in the 0.69PMN-0.31PT ceramics prepared by the B-site oxide mixing route, being 32232 at 1 kHz. All the synthesized 0.69PMN-0.31PT ceramics exhibit typical ferroelectric phase transition with slightly diffused character, fully developed, saturated and symmetric P-E hysteresis loops, and excellent piezoelectric property. Ceramic processings exert great effects on electrical properties of the synthesized ceramics. Comparatively, the 0.69PMN-0.31PT ceramics prepared by the B-site oxide mixing route exhibit excellent electrical properties. [ABSTRACT FROM PUBLISHER]

Phase-pure perovskite structure (KxLa0.05-x)Ba0.95TiO3 ceramics were prepared by the conventional solid-state reaction method. With the increase of the ratio of K/La, crystal structure of the (KxLa0.05-x)Ba0.95TiO3 ceramics changes gradually from pseudo-cubic perovskite structure to tetragonal one. The sintered (KxLa0.05-x)Ba0.95TiO3 ceramics exhibit rather high relative density and rather homogenous microstructure morphology composed of submicron grains. With the decrease of the ratio of K/La, the temperature of dielectric constant maximum (TC or Tm) decreases almost linearly, and the dielectric response character of the (KxLa0.05-x)Ba0.95TiO3 ceramics changes from narrow and sharp dielectric peaks to broad and diffused ones gradually accompanied by the increase of dielectric frequency dispersion. The (KxLa0.05-x)Ba0.95TiO3 ceramics exhibit rather slim P-E hysteresis loops with slight character of asymmetry. Via adjusting the ratio of K/La, the acceptor and donor doping states are tailored, therefore, excellent ferroelectric and piezoelectric properties can be obtained in the (KxLa0.05-x)Ba0.95TiO3 ceramics. [ABSTRACT FROM PUBLISHER]