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1.
Guochu Deng Qingrui Yin Aili Ding Xinsen Zheng Wenxiu Cheng Pingsun Qiu 《Journal of the American Ceramic Society》2005,88(8):2310-2314
La-doped 0.3Pb(Zn1/3 Nb2/3 )O3 –0.7Pb(Zr x Ti1− x )O3 ( x =0.5–0.53) piezoelectric ceramics with pure perovskite phase were synthesized by a two-step hot-pressing route. The piezoelectric properties of various compositions near the morphotropic phase boundary (MPB) were systematically investigated. Not only was the exact MPB of this system determined via X-ray diffractometry analysis, but also the peak of piezoelectric properties was found near the MPB. The optimum piezoelectric properties of this series were observed in the specimen with Zr/Ti=51/49. The piezoelectric coefficient ( d 33 ) and electromechanical coupling factor ( k p ) were 845 pC/N and 0.70, respectively, which have not been reported in this system so far. Large permittivity (ɛr =4088) and permittivity maximum (ɛm =29 500) were also obtained for the poled specimens. The temperatures ( T max ) of the permittivity maxima ranged from 206° to 213°C with various Zr/Ti ratios. 相似文献
2.
The elastic and piezoelectric properties of PLZT ceramics with a 65/35 Zr/Ti ratio undergo pronounced changes as La is added to the structure. At the rhombohedral-tetragonal phase boundary, material constants plotted as functions of La concentration show strong discontinuities in slope; these discontinuities provide a precise means of locating the boundary. The radial-mode coupling factor, kp , compliance coefficient, S11 E , and piezoelectric coefficient, d31 , attain peak values at the boundary, whereas Poisson's ratio, σE , and the resonance-frequency constant exhibit pronounced minima. This behavior is evidence of the increasing ferroelastic sensitivity of the material as the distortion angle of the rhombohedral phase approaches a minimum. 相似文献
3.
Else Breval Maria Klimkiewicz Chiping Wang Joseph P. Dougherty Ann Crespi 《Journal of the American Ceramic Society》2007,90(7):2043-2049
The sinterability and decomposition of PLZT, (Pb,La)(Zr,Ti)O3 , depend on the temperature and soaking time of both the calcination and sintering temperature. They were determined from the density, linear shrinkage, weight loss, and appearance of extra phases. At moderate calcination temperatures and times, there is no escape of PbO from the PLZT. At calcination temperatures higher than 1050°C and soaking times above 3 h, PbO escapes, and ZrO2 and La2 Zr2 O7 can be detected. Even when sintered in a PbO-rich atmosphere, some PbO evaporates during sintering either from free PbO or from the PbO bound in the PLZT in regions in the outer surfaces of the sintered body. An aggressive depletion of PbO during sintering can result in a complete disappearance of the grain boundary phase, giving an intragranular fracture. 相似文献
4.
Jin-Rong Cheng Richard Eitel L. Eric Cross 《Journal of the American Ceramic Society》2003,86(12):2111-2115
(1 – x )(Bi0.8 La0.2 )(Ga0.05 Fe0.95 )O3 · x PbTiO3 (BLGF-PT) crystalline solutions have been fabricated by solid-state reactions. BLGF-PT has single perovskite phase structure with a rhombohedral–tetragonal (FEr -FEt ) morphotropic phase boundary (MPB) at a PT content of x = 0.43. Lanthanum substitution has been found to increase the insulation resistance and decrease the coercive field down to 20 kV/cm, which results in significant improvements in dielectric and piezoelectric properties of BLGF-PT. The dielectric constant, loss tangent, Curie temperature, remnant polarization, piezoelectric d 33 constant, and planar coupling factor of 1760, 0.05, 264°C, 33 μC/cm2 , 295 pC/N, and 0.36, respectively, have been achieved for BLFG-PT in the vicinity of the MPB. Compared with conventional Pb(Zr,Ti)O3 (PZT) piezoelectric ceramics, the BLGF-PT is a competitive alternative piezoelectric material with decreased lead content. 相似文献
5.
Shoji Kaneko Dunzhuo Dong Kenji Murakami 《Journal of the American Ceramic Society》1998,81(4):1013-1018
Sintering of 0.5-wt%-MnO2 -added Pb(Zr0.53 Ti0.47 )O3 ceramics progresses at 935°C for 50 min by the addition of complex oxides of perovskite-type crystal structure, BiFeO3 and Ba(Cu0.5 W0.5 )O3 . In order to elucidate the low-temperature sintering mechanism of Pb(Zr,Ti)O3 ceramics, the shrinkage and the evolution of the microstructure of a compacted body during heating were studied. It has been shown that the densification process was separated into the following three stages: the rearrangement of grains, the grain boundary diffusion of atoms, and then grain growth. Also, microstructural and elemental analyses of the ceramics revealed the existence of an amorphous phase at the grain boundaries predominantly composed of lead and copper oxides. Consequently, this process can be facilitated by the occurrence of a transient liquid phase corresponding to the above amorphous phase. 相似文献
6.
Kazuyuki Kakegawa Jun-Ichi Mohri Shin-Ichi Shirasaki Koichiro Takahashi 《Journal of the American Ceramic Society》1984,67(1):2-C-3
An organic chelation reagent, cupferron, was used to coprecipitate Ti4+ andZr4+ . After the materials were fired, they were mixed with PbO powder and fired again at high temperatures to obtain Pb(Zr,Ti)03 (PZT). It was confirmed that this method is useful for the preparation of homogeneous PZT having no compositional fluctuations. No coexistence range of the tetragonal and rhombohedral phases was observed in the PZT compositions near the morphotropic phase boundary. 相似文献
7.
Else Breval Chiping Wang Joseph P. Dougherty Kamau wa Gachigi 《Journal of the American Ceramic Society》2005,88(2):437-442
The room temperature phase diagram of PLZT, (Pb,La)(Zr,Ti)O3 , or L / Z / T for L <12 and T <10 was constructed using X-ray diffraction patterns of sintered and crushed PLZT material. The orthorhombic antiferroelectric phase, a tetragonal phase, the rhombohedral (hexagonal) ferroelectric phases, and the mixed La-rich zone were identified. Increasing substitution of La for Pb in the structure of orthorhombic PLZT leads to a change toward the cubic structure with less anisotropy in a direction corresponding to the cubic 200 direction. At La above ∼8 to 11 mol%, La2 Zr2 O7 appears in the mixed zone. With increasing substitution of Ti for Zr, there is no change toward a cubic structure as the anisotropy is nearly unchanged. However, at a Ti substitution above ∼6 mol%, a rhombohedral and a tetragonal structure appear. 相似文献
8.
HIROMU OUCHI 《Journal of the American Ceramic Society》1968,51(3):169-176
When a small amount of Ba or Sr is substituted for Pb in Pb(Mg1/3 Nb2/3 )O3 -PbTiO3 -Pb2rO 3 , the morphotropic boundary and the compositions which show the highest planar coupling coefficient and dielectric constant shift slightly toward the decreasing PbTiO3 content. The tetragonality of Pb(Mg1/3 Nb2/3 )O3 -PbTiO3 and Pb(Mg1/2 Nb2/3 )-O3 -PbTiO3 -PbZrO3 ceramics decreased with increasing Ba or Sr content. The lattice parameter (α axis) in the rhombohedral or pseudocubic phase increased with the increase of Ba but decreased with the increase of Sr substitution. Although the Curie temperature was lowered with the increase of Ba or Sr, the dielectric constants of the ceramics were increased. The dielectric and piezoelectric properties of the ternary compositions near the morphotropic boundary were improved through selection of sub-stituent and base composition. A planar coupling coefficient of 0.66 and a low Young's modulus were obtained with substitution of 5 mole % Ba. A dielectric constant greater than 3500 and a planar coupling of 0.63 can be obtained by substituting 5 mole % Sr. 相似文献
9.
K. KAKEGAWA J. MOHRI S. SHIRASAKI K. TAKAHASHI 《Journal of the American Ceramic Society》1982,65(10):515-519
Tetragonal and rhombohedral phases always coexist in Pb(Zrx Til1−x )03 near the morphotropic phase boundary compositions (0.52≤x≤0.55) when prepared by solid-solid reaction among the constituent oxides. A special technique was developed to obtain perovskite ceramics exhibiting no co-existence in the boundary compositions, in which no compositional fluctuation occurred in the B site of the perovskite structure. Even these monophasic perovskite ceramics of the morphotropic phase boundary compositions were two-phase with the lapse of time after poling. This phenomenon is interpreted in terms of thermodynamics. It is suggested that this phenomenon may closely relate to the origin of aging in piezoelectrics. 相似文献
10.
BiScO3 –PbTiO3 (BSPT) thin films near the morphotropic phase boundary were successfully fabricated on Pt(111)/Ti/SiO2 /Si substrates via an aqueous sol–gel method. The thin films exhibited good crystalline quality and dense, uniform microstructures with an average grain size of 50 nm. The dielectric, ferroelectric, and piezoelectric properties of the sol–gel-derived BSPT thin films were investigated. A remanent polarization of 74 μC/cm2 and a coercive field of 177 kV/cm were obtained. The local effective piezoelectric coefficient d * 33 was 23 pC/N at 2 V, measured by a scanning probe microscopy system. The dielectric peak appeared at 435°C, which was 80°C higher than that of Pb(Ti, Zr)O3 thin films. 相似文献
11.
Gilles Robert Marlyse Demartin Dragan Damjanovic 《Journal of the American Ceramic Society》1998,81(3):749-753
A phase diagram based on dielectric-permittivity-versus-temperature measurements and high-temperature X-ray diffractometry was proposed for 0.4Pb(Ni1/3 ,Nb1/3 )O3 - x PbZrO3 -(0.6- x )PbTiO3 (0.2 lessthan equal to x lessthan equal to 0.32) relaxor-ferroelectric solid solution, and a morphotropic phase boundary that sharply bends toward zirconium-rich compositions was found. A spontaneous normal-to-relaxor ferroelectric transition was also observed when heating was performed for all the compositions tested near the morphotropic phase boundary. Additional considerations about previously published phase diagrams for Pb(Zn1/3 ,Nb2/3 )O3 -PbTiO3 and Pb(Mg1/3 ,Nb1/3 )O3 -PbTiO3 might lead to an extension of the presented diagram to these compositions. 相似文献
12.
Defect Structure of PLZT Doped with Mn, Fe, and Al 总被引:2,自引:0,他引:2
K. H. Härdtl 《Journal of the American Ceramic Society》1981,64(5):283-288
Practically pore-free Mn-, Fe-, and Al-doped PLZT ceramics were prepared using isostatic hot-pressing. The incorporation of the dopants in the perovskite lattice of PLZT (Pb0.9 La0.1 |Zr0.5 Tio.5 O3+ δ) ceramics was analyzed from measurements of the density, lattice constants, and weight loss during sintering. It was deduced that Mn, Fe, and Al are incorporated as trivalent ions at (Zr, Ti)4+ sites and that charge compensation is effected by elimination of cation vacancies present in the undoped PLZT. 相似文献
13.
Kazuyuki Kakegawa Osamu Matsunaga Tamani Kato Yoshinori Sasaki 《Journal of the American Ceramic Society》1995,78(4):1071-1075
Compositional changes which take place during sintering of Pb(Zr,Ti)O3 (PZT) containing excess PbO were studied. The excess PbO forms a liquid phase during the sintering process. The solubility of the TiO2 component of PZT in liquid PbO is higher than that of ZrO2 component. Thus, if an excess PbO exists, the composition of PZT phase shifts towards the Ti-lean side. A change in the lattice constants due to this compositional change was actually observed. Coexistence of tetragonal and rhombohedral phases, due to a compositional fluctuation caused by excess PbO, was observed near the morphotropic phase boundary. When PZT containing excess PbO was sintered at 1100°C, a compositional fluctuation occurred early in the process and then decreased with sintering time. These phenomena have agreed with a result of computer simulation of dissolution of TiO2 component in PZT phase into liquid PbO phase. 相似文献
14.
S. S. N. Bharadwaja T. Dechakupt S. Trolier-McKinstry H. Beratan 《Journal of the American Ceramic Society》2008,91(5):1580-1585
A KrF pulsed excimer laser (248 nm) was utilized to crystallize sputtered La-modified Pb(Zr,Ti)O3 (3:30:70) (PLZT) films on LaNiO3 -coated silicon substrates. The film surface was irradiated with defocused laser pulses in an oxygen ambient at various substrate temperatures. Polycrystalline, phase pure perovskite PLZT thin films were produced for substrate temperatures of 250°C and higher. The dielectric constant and loss tangent values of laser-assisted crystallized (10 min exposure at 10 Hz using a substrate temperature of 400°C) PLZT thin films at 10 kHz were 406 and 0.027; in comparison, rapid thermal annealed films (annealed at 700°C for 1 min) showed values of 400 and 0.021, respectively. Laser crystallized films exhibited a remanent polarization value of 14 μC/cm2 with a coercive field |( E +c + E −c )|/2 of 95 kV/cm. 相似文献
15.
Reaction Mechanisms in the Formation of Lead Zirconate Titanate Solid Solutions under Hydrothermal Conditions 总被引:1,自引:0,他引:1
Humin Cheng Jiming Ma Bin Zhu Yuhong Cui 《Journal of the American Ceramic Society》1993,76(3):625-629
Reaction mechanisms in the formation of PZT solid solution were studied under hydrothermal conditions (Pb/(Zr+Ti) = 1.0 to 1.9, Zr/Ti = 0/10 to 10/0, 1 M to 5 M KOH, 100° to 220°C, 2 h). A yellow tabular crystallite with tetragonal symmetry and Pb/Ti ∼ 2 was formed at 100° to 130°C. A PZT crystallite was formed just above 150°C. The crystallite was a mixture of Ti-rich PZT and Zr-rich PZT phases. When the temperature and KOH concentration were increased, the composition of the PZT product tended to be homogeneous. The PZT in the morphotropic phase boundary zone was formed at Zr/Ti = 5/5, 5M KOH, 220°C, 2 h. Neither PbTiO3 nor PbZrO3 was detected as a separate phase under the above hydrothermal conditions. 相似文献
16.
Bo Li Ji Zhou Qi Li Longtu Li Zhilun Gui 《Journal of the American Ceramic Society》2003,86(5):867-869
(Pb,La)(Zr,Ti)O3 (PLZT) inverse opal photonic crystals were synthesized by a sol-gel process with synthetic opal templates of monodisperse submicrometer polystyrene spheres. This process involves infiltration of precursors into the interstices of the opal template, followed by hydrolytic condensation of the precursors and removal of the polystyrene opal combined with crystallization of PLZT perovskite by calcination at a final temperature of 750°C. By this method, PLZT inverse opal photonic crystals with a periodical structure of 280 nm center-to-center distance between the air spheres are prepared from opal templates of polystyrene microspheres with a mean diameter of 400 nm. The PLZT inverse opals reflect yellow-green light strongly. 相似文献
17.
Yong Jun Wu Juan Li Xiang Ming Chen Ryo Kimura Kazuyuki Kakegawa 《Journal of the American Ceramic Society》2008,91(1):13-16
The effects of La2 O3 addition and PbO excess on the microstructures and optical properties of PbZrO3 –PbTiO3 –Pb(Zn1/3 Nb2/3 )O3 (PZ–PT–PZN) ceramics prepared by spark plasma sintering were investigated. When 1 mol% La2 O3 was added, the highest transmittance of 35% at 700 nm for PZ–PT–PZN ceramics was obtained. The improved transmittance was attributed to the increased relative density and the decreased optical anisotropy. The samples containing more than 1 mol% La2 O3 showed decreased transmittance, due to the appearance of secondary phases. The transmittance of PZ–PT–PZN ceramics increased slightly to 29% at 700 nm with increasing amount of excess PbO up to 10 mol% and thereafter decreased rapidly. 相似文献
18.
Weizhong Zhu rei L. Kholkin Pedro Q. Mantas Joao L. Baptista 《Journal of the American Ceramic Society》2001,84(8):1740-1744
The morphotropic phase boundary (MPB) in the relaxor ferroelectric system Pb(Zn1/3 Nb2/3 O3 )-BaTiO3 -PbTiO3 (PZN-BT-PT) with 15 mol% BT was investigated through dielectric permittivity and high-temperature X-ray diffraction measurements. It was revealed that MPB is a broad composition region extending from 12 to 18 mol% PT, within which the temperatures of the permittivity maximum are close to the ending temperatures for the phase transformation from coexisting rhombohedral and tetragonal phases to cubic phase on heating. When the specimen is cooled, the starting temperatures for the rhombohedral-to-tetragonal phase transition increase with increasing PT content. The large thermal hysteresis observed by X-ray diffraction is caused by the phase transformation between rhombohedral and tetragonal phases. On cooling, the MPB curves toward the PT-rich side, so that ceramics within this composition range undergoe successive phase transitions from cubic to rhombohedral and from rhombohedral to tetragonal phase. The diffuseness of the paraelectric-to-ferroelectric phase transition is remarkably decreased by the addition of PT. The enhanced dielectric permittivity peak values for the MPB compositions are correlated with the reduced lattice distortion and phase coexistence. 相似文献
19.
Miguel Algueró Carlos Alemany Lorena Pardo Mai Pham-Thi 《Journal of the American Ceramic Society》2005,88(10):2780-2787
A method based on the use of four piezoelectric resonances for three sample geometries that allows obtaining the full set of linear electric, mechanical, and electromechanical coefficients, and all related losses of a piezoelectric ceramic has been applied to Mn-doped 0.655Pb(Mg1/3 Nb2/3 )O3 –0.345PbTiO3 at the morphotropic phase boundary (MPB PMN–PT). Length-poled MPB PMN–PT ceramic plates presented piezoelectric shear double resonances associated with a thickness gradient of tetragonal and rhombohedral (or monoclinic) phases that originated during poling. The versatility of the method still allowed addressing these double resonances and obtaining all the linear coefficients and losses of the well-poled material. These are given for MPB PMN–PT and compared with those of a Navy type II Pb(Zr,Ti)O3 (PZT) ceramic. MPB PMN–PT presents piezoelectric coefficients as high as soft PZT but significantly lower losses, and so less overheating and hysteresis under high driving fields. Its thermal stability has been studied up to 100°C, and the temperature dependence of a number of linear coefficients and of the thickness and planar coupling factors and frequency constants of disks has been obtained. The latter thickness parameters hardly changed with temperature, while planar ones showed a relative variation of 10%. 相似文献
20.
Abhijit Pramanick John E. Daniels Jacob L. Jones 《Journal of the American Ceramic Society》2009,92(10):2300-2310
Structural changes such as non-180° domain wall motion and lattice strains in Pb(Zr,Ti)O3 ceramics are measured during the application of subcoercive cyclic electric fields using time-resolved high-energy X-ray diffraction with a stroboscopic data collection technique. The contributions to the electric-field-induced strains from non-180° domain wall motion and lattice distortions are determined as a function of material composition and type of dopant. For the different compositions studied, the largest strains due to non-180° domain wall motion are measured for La-doped tetragonal ceramics with a composition close to the morphotropic phase boundary. It is further observed that strain contributions from both non-180° domain wall motion and lattice distortions can be nonlinear with respect to the applied electric field. The correlation between the electric-field-induced structural changes and the macroscopic piezoelectric properties is discussed. 相似文献