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Lead zirconate titanate-based piezoelectric ceramics (Pb 0·91 La 0·06 (Zr 0·58 Ti 0.42) 0.975 Nb 0·02 O 3 , PLZT) were prepared by water-soluble defatted powder injection molding using bismuth stearate as surfactant. The effects of bismuth stearate surfactant amount on the feed viscosity, water degreasing rate and electrical properties were studied. The results showed that the bismuth stearate coating reduces agglomeration between the PLZT powders and decreases the viscosity of the feed. During sintering, bismuth stearate is decomposed into bismuth oxide, which acts as sintering aid to increase the density of the sintered bismuth stearate-coated PLZT ceramics. Bi3+ dissolves into the perovskite crystal lattice, which increases the tetragonality factor and the content of tetragonal phase, and improves the dielectric, ferroelectric and piezoelectric properties of the bismuth stearate-coated PLZT ceramics. This study provides a novel modification method for the production of injection molded ceramics using a water-soluble binder system. [ABSTRACT FROM AUTHOR]

Acrylic resin and PLZT (Pb0.910La0.060 (Zr0.580Ti0.420)0.975Nb0.020O3.000) powder were mixed to prepare PLZT/acrylic resin thermosetting feedstock. Injection molding is used to form high-strength PLZT piezoelectric ceramic embryos then sintered to piezoelectric materials. The experimental results showed that the residual polarization is higher at 85% solid content of the feed and the d33 value increased. And the PLZT powder coated with stearic acid can improve the piezoelectric and ferroelectric properties of powder injection molded piezoelectric ceramics. Tests above are intended to provide preliminary exploration for thermal curing injection molding and thermal curing 3 D printing piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

(Ba0.85Ca0.15)(Hf0.10Ti0.90)O3 (BCHT) lead-free piezoelectric ceramics were synthesized via the powder injection molding process sintered at several temperatures, in which the BCHT ceramics were prepared by the conventional ceramic processing sintered at the optimized temperature 1450 °C for comparison. All the synthesized BCHT ceramics exhibit rather pure perovskite phase structure, where the BCHT ceramics prepared via the powder injection molding process present more apparent multiphases coexistence characteristic. The electrical properties of the BCHT ceramics prepared via the powder injection molding process are slightly better than those prepared by the solid-state sintering method, which correlate with the increase of ceramics densification and the change of grains micro-morphology. The powder injection molding technique provides a feasible way to synthesize irregular shaped piezoelectric ceramics with excellent electrical performance. [ABSTRACT FROM AUTHOR]

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]

Antiferroelectric analogous (Pb0.92Sr0.05La0.02)(Zr0.7Sn0.25Ti0.05)O3 (PSLZSnT) ceramics were prepared by the solid-state sintering method by introducing a Y2O3-coating via the self-combustion method. The synthesized Y2O3-doped PSLZSnT ceramics present pseudo-cubic structure and rather uniform microstructural morphology accompanied by relatively small grain size. Excellent energy-storage performance is obtained in the Y2O3-doped PSLZSnT ceramics, in which the value of the energy-storage density presents a linearly increasing trend within the electric field measurement range. Such excellent performance is considered as relating to the rather pure perovskite structure, high relative density accompanied by relatively small grain size, and the antiferroelectric-like polarization-electric field behavior. [ABSTRACT FROM AUTHOR]

Ferroelectric phase transition characteristic and electrical conduction mechanism of the high Curie-point (T C ) 0.15Pb(Mg 1/3 Nb 2/3 )O 3 −0.4PbHfO 3 −0.45PbTiO 3 (PMN-PHT) piezoelectric ceramics were studied by the temperature dependent Raman spectra and electrical properties. Sole first-order ferroelectric phase transition is demonstrated by the thermal hysteresis behavior of the temperature dependent dielectric constant and the dramatic drop of the derivative of inverse dielectric constant ξ= d(1/ε r )/dT around T C in the PMN-PHT ceramics. The temperature dependent Raman spectroscopy not only provides further evidence for the ferroelectric to paraelectric phase transition appearing around T C in the PMN-PHT ceramics, but also reveals the successive phase symmetry changes of the polar nanoregions (PNRs), in which apparent anomalies appear in the Raman peaks' wavenumber, wavenumber distance, intensity, intensity ratio, and line width of some selected Raman modes upon heating. Typical sole cole-cole circle is obtained for the PMN-PHT ceramics in the temperature range of 440–560 °C, based on which the activation energy (E a ) of the electrical conduction is calculated being ~1.2 eV. Such low value of E a indicates that the oxygen vacancies formed in the PHT-PMN ceramics induced by the evaporation of Pb during the sintering process dominate the high-temperature extrinsic electrical conduction. [ABSTRACT FROM AUTHOR]