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Titanate
Kinds of Titanate Terms modified by Titanate Selected AbstractsGiant Electric Field Tuning of Magnetism in Novel Multiferroic FeGaB/Lead Zinc Niobate,Lead Titanate (PZN-PT) HeterostructuresADVANCED MATERIALS, Issue 46 2009Jing Lou A novel multiferroic heterostructure consisting of a FeGaB thin film and a PZN-PT single crystal slab shows giant tunability of the ferromagnetic resonance (FMR) frequency of the heterostructure by electric field (see figure). The overall electric-field-induced FMR frequency change of 5.82 GHz is the largest reported so far. FeGaB/PZN-PT multiferroic heterostructures are promising candidates for wide-band electrostatically tunable microwave devices. [source] Texture Development in Barium Titanate and PMN,PT Using Hexabarium 17-Titanate HeterotemplatesINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2005Toshio Kimura Bulk BaTiO3 ceramics with ,111,-texture have been prepared by the modified templated grain growth method, using platelike Ba6Ti17O40 particles as templates, and the mechanism of texture development is examined. The Ba6Ti17O40 particles induce the abnormal growth of BaTiO3 grains, and a structure similarity between {001} of Ba6Ti17O40 and {111} of BaTiO3 gives ,111,-texture to abnormally grown BaTiO3 grains. Thus, the ,111,-texture develops in the BaTiO3 matrix. The use of platelike Ba6Ti17O40 particles has been extended to a 0.65Pb(Mg1/3Nb2/3)O3,0.35PbTiO3 matrix, but the matrix phase is decomposed by extensive chemical reactions between the matrix and template phases. [source] Microwave-Induced-Plasma-Assisted Synthesis of Ternary Titanate and Niobate Phases,ADVANCED MATERIALS, Issue 20 2005J. Brooks Microwave-induced plasmas of argon (see Figure) and dioxygen have been used to rapidly prepare ternary niobate and titanate phases directly in the solid state from precursors that do not exhibit microwave heating at room temperature. However, for some reactions heating of the microwave-induced plasma can promote dielectric loss, which allows access to local temperatures greater than the equilibrium plasma temperature. [source] Infrared Spectra of U.S. Automobile Original Finishes.JOURNAL OF FORENSIC SCIENCES, Issue 3 2006ABSTRACT: The identification, analysis, and occurrence in U.S. automobile original finishes (1974,1989) of Nickel Titanate (yellow) and Chrome Titanate (yellow,orange) are described in this report. The titanate pigments are based on the rutile (titanium dioxide) structure and there are only minor differences between the infrared absorptions of rutile and the titanates. Titanate pigment absorptions in paint spectra can thus be easily mistaken for those of rutile. Each of the titanates, however, contains two elements in addition to titanium that can serve to distinguish them using elemental analyses. Fourier transform infrared (4000,220 cm,1) and X-ray fluorescence instruments were used in combination for the in situ analysis of the titanates. In addition to titanium, nickel, and antimony, the three main detectable elements comprising Nickel Titanate, all of the commercial products of this pigment that were examined also contained impurities of zirconium, niobium, and usually lead. These elements were also detected in most of the monocoats in which Nickel Titanate was identified, as well as in the Chrome Titanate pigments, and the zirconium to niobium ratio was found to exhibit a wide variation. Nickel Titanate is a relatively common pigment that was identified in nearly three dozen U.S. automobile yellow nonmetallic monocoats (1974,1989), while Chrome Titanate appears to have been used in only a few yellow and orange nonmetallic monocoats. The use of the titanate pigments likely increased after this time period as they were replacements for lead chromate pigments (last used in a U.S. automobile original finish in the early 1990s), and are more amenable for use in basecoat/clearcoat finishes than in monocoats. Minor distortions of the infrared absorptions of rutile, anatase, and the titanates obtained using accessories with diamond windows were noted, and their origins are discussed. [source] Electric and Dielectric Behaviors of Y-Doped Calcium Copper TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2010Fengchao Luo Yttrium-doped CaCu3Ti4,xYxO12,x/2 (x=0,0.1) samples were fabricated by using solid-state sintering, and their electric and dielectric properties were investigated. Yttrium addition has shown to reduce the dielectric loss remarkably while maintaining colossal permittivity. At x=0.5, the loss (tan ,) is below 0.1 over the frequency range from 1 to 300 KHz, while that of the pure ceramic is above 0.1 over most measuring frequency range. The current density,electric field curves proved that yttrium doping can effectively enhance the varistor voltage, indicating a rise of the potential barrier height at the grain boudaries. Local measurement of impedance at the grain boundaries was performed by using microcontact probes. The results indicated that yttrium dramatically increases the resistance of the grain boundaries. The differences are attributed to the enhanced Cu segregation at grain boundaries, which is induced by yttrium doping. [source] Strength Properties of Poled Lead Zirconate Titanate Subjected to Biaxial Flexural Loading in High Electric FieldJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Hong Wang The mechanical strength of poled lead zirconate titanate (PZT) has been studied using ball-on-ring (BoR) biaxial flexure tests with a high electric field applied concurrently. Both the as-received and the aged PZT specimens were tested. The Weibull plot and a 95% confidence ratio ring were used to characterize the responses of mechanical strength under various electric loading conditions. A fractographical study has been conducted at the same time, and the fracture origins or strength-limiting flaws of tested PZT specimens have been identified and characterized accordingly. The fracture toughness was further estimated to correlate with the obtained fracture stresses and flaws. It has been observed that electric field affects the mechanical strength of poled PZT, and the degree of the effect depends on the sign and magnitude of the applied electric field. Within the examined electric field range of ,3 to +3 times the coercive field, an increasing electric field resulted in a rapid strength decrease and a sharp increase with the turning point around the negative coercive field. Surface-located volume-distributed flaws were identified to be strength limiting for this PZT material. Variations of the mechanical strength with the electric field were believed to be related to the domain switching and amount of switchable domains. An aging effect on the mechanical strength of poled PZT could be significant, especially in the OC condition. These results and observations have the potential to serve probabilistic reliability analysis and design optimization of multilayer PZT piezo actuators. [source] Sodium Bismuth Titanate-Based Lead-Free Piezoceramics Prepared by Aqueous GelcastingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2008Dongxiang Zhou Aqueous gelcasting for 0.94Bi0.5Na0.5TiO3,0.06BaTiO3 (BNBT6) lead-free piezoceramics was investigated in this paper. A stable BNBT6 suspension with 50 vol% of solid loading and <1Pa·s of viscosity was successfully prepared when 0.5 wt% of PMAA-NH4 was added with the pH value controlled in the range 8,10. Dehydration and desiccation of the gelled parts could be controlled easily through dipping pretreatment with a 5 wt% ammonium persulfate solution for 24 h or with a 10 wt% ammonium persulfate solution for 12 h. Scanning electron microscopy micrographs show that the BNBT6 ceramic prepared by the gelcasting route exhibits a homogeneous microstructure and a high density. Optimal piezoelectric and dielectric properties were obtained: d33=132pC/N, , tg ,=0.019, and kp=0.25. [source] Modified Phase Diagram for the Barium Oxide,Titanium Dioxide System for the Ferroelectric Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2007Soonil Lee The ferroelectric phase transition behavior in BaTiO3 was investigated for various annealing times, temperatures, and Ba/Ti ratios by means of a differential scanning calorimeter. Coupling these observations with powder X-ray diffraction and transmission electron microscopy allowed new insights into the barium oxide (BaO),titanium dioxide (TiO2) phase diagram. The transition temperature was varied systematically with the Ba/Ti ratio at annealing temperatures from 1200° to 1400°C in air. The transition temperature decreased with increasing concentrations of BaO and TiO2 partial Schottky defects, and showed a discontinuous change at the phase boundaries. Beyond the solubility region, two peritectoid reactions were confirmed and revised; first around 1150°C for Ba1.054Ti0.946O2.946,Ba2TiO4+BaTiO3 and second 1250°C for BaTi2O5,Ba6Ti17O40+BaTiO3, respectively. All other regimes of the BaO,TiO2 were found to be consistent with the reported diagrams in the literature. [source] Domain Switching Under Cyclic Mechanical Loading in Lead Zirconate TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2006Soodkhet Pojprapai (Imlao) The domain-switching behavior of lead zirconate titanate (PZT) during mechanical cyclic loading between 10 and 150 MPa was investigated by in situ time-of-flight neutron diffraction. The domain-switching behavior was represented by a change of the pole density distribution during cycling. With increasing number of cycles, domain switching becomes saturated, correlating with a decrease in the rate of remnant strain accumulation in the stress,strain curve. Moreover, a relationship was demonstrated between the macroscopic strain and that developed from ferroelastic domain switching. The contribution of ferroelastic strain to the macroscopic strain was calculated from an orientation average of the domain switching distributions and the c/a ratio. The results show that nearly 80% of macroscopic strain arises from ferroelastic domain switching during mechanical cyclic loading. [source] Crystallographic Texture Development in Bismuth Sodium Titanate Prepared by Reactive-Templated Grain Growth MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2004Toshio Kimura Bi0.5Na0.5TiO3 (BNT) and 0.94Bi0.5Na0.5TiO3·0.06BaTiO3 (BNT,BT) bulk ceramics with extensive ,100, texture were prepared by the reactive-templated grain growth method, using platelike Bi4Ti3O12 (BIT) particles as templates for BNT. Calcined compacts were composed of matrix grains with random orientation and ,100,-oriented grains transformed from aligned BIT particles, and the texture developed by the growth of oriented grains during sintering. Ceramics with extensive texture were obtained by using the starting mixture containing the maximum concentration of platelike BIT to form the maximum volume fraction of oriented grains. [source] Subcritical Crack Growth in Lead Zirconate TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2004William S. Oates Subcritical crack growth in terms of velocity,stress intensity factor (v,K) curves in lead zirconate titanate (PZT) were experimentally characterized on poled and unpoled compact tension specimens. The poled specimens were tested under open- and short-circuit electrical boundary conditions, which resulted in an increase in fracture toughness by 0.2 MPa·m1/2 for the accessible velocity range (v= 10,9 to 10,4 m/s) in the open-circuit case. Subcritical crack growth of unpoled specimens was obtained under ambient (relative humidity = 35%) and dry (relative humidity , 0.02%) conditions over a regime in stress intensity factor of 0.5 MPa·m1/2. [source] Sintering of Lead Titanate Using a Spark-Plasma-Sintering TechniqueJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2004Kazuyuki Kakegawa Lead titanate (PbTiO3) is difficult to sinter without additives, even when a spark-plasma-sintering technique is applied. The high tetragonality, c/a, of PbTiO3 causes destructive strain after sintering. We found that a sintered body of PbTiO3 could be obtained, when the PbO/TiO2 value was <0.9. However, decreasing the ratio did not increase the bulk density; rather, it caused a decrease in the grain size. The mechanical strain that resulted from the phase change from cubic, at the sintering temperature, to tetragonal, at room temperature after the sintering, was released by the decrease in the grain size. [source] Crack,Tip Toughness of a Soft Lead Zirconate TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2003Alain B. Kounga Njiwa Crack,opening displacement (COD) measurements were performed on a commercial lead zirconate titanate (PZT). The intrinsic fracture toughness (or crack,tip toughness) of this material was determined using a new evaluation procedure, which takes into account the near,tip CODs and complete crack profile CODs. The crack,tip toughness KI0 was determined from an extrapolation of COD data obtained at various loading stages, thus avoiding the complications caused by subcritical crack growth in PZT. Results for plane strain and plane stress condition are presented. [source] Effect of the Liquid-Phase Characteristic on the Microstructures and Dielectric Properties of Donor- (Niobium) and Acceptor- (Magnesium) Doped Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2003Seok-Hyun Yoon Changes in the microstructure and dielectric properties with the variation of the donor/acceptor ratio in BaTiO3 ceramics were investigated. In donor-rich specimens, a liquid that appeared during sintering did not penetrate into grain boundaries. However, in the acceptor-rich specimens, the grains were separated by a liquid film during sintering. The much higher mobility of the liquid film than that of the grain boundaries was suggested to cause extensive grain growth in acceptor-rich BaTiO3. The macroscopic homogenization of dopants because of grain growth in acceptor-rich specimens resulted in changes in the dielectric properties. [source] {111} Twin Formation and Abnormal Grain Growth in Barium Strontium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2003Byoung-Ki Lee Two series of experiments were performed to study the experimental conditions for the formation of {111} twins and related microstructures in barium strontium titanate ((Ba, Sr)TiO3). In the first series, the phase equilibria in the BaTiO3,SrTiO3,TiO2 system were determined. XRD and WDS analysis, done in the BaTiO3 -rich region, of 45(Ba,Sr)TiO3,10TiO2 samples annealed at 1250°C for 200 h in air showed that (Ba,Sr)TiO3 was in equilibrium with Ba6Ti17O40 (B6T17) and Ba4Ti13O30 phases with strontium solubility (Sr/(Ba + Sr)) of ,0.02 and 0.20, respectively. In the second series the microstructures of samples consisting of a mixture of (Ba,Sr)TiO3 and 2.0 mol% TiO2, were observed after sintering at 1250°C for 100 h in air. {111} twins formed only in the samples with faceted B6T17 second phase particles, similar to the case of BaTiO3. In these samples, abnormal grain growth occurred in the presence of the {111} twins. In contrast, no {111} twins formed and no abnormal grain growth occurred in the samples containing second phase particles other than B6T17. With an increased substitution of strontium for barium, the aspect ratio of abnormal grains containing {111} twin lamellae was reduced. This result was attributed to a reduction in the relative stability of the {111} planes with the strontium substitution. [source] Factors Determining Grain Orientation in Bismuth Sodium Potassium Titanate,Lead Zirconate Titanate Solid Solutions Made by the Reactive Templated Grain Growth MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2002Yuichi Abe Grain-oriented Bi0.5(Na0.85K0.15)0.5TiO3 -Pb(Zr1,xTix)O3 (BNKT-PZT) ceramics were prepared via the reactive templated grain growth method, using platelike Bi4Ti3O12 particles. Factors that determine the degree of orientation were examined. Prereacted PZT gave a larger degree of orientation than PZT raw materials (PbO, ZrO2, and TiO2) in the 75BNKT-25PZT (x= 0.5) system. Increases in the titanium concentration in the PZT of the 75BNKT-25PZT system and in the BNKT concentration in the yBNKT-(100 ,y)PZT (x= 0.5) system increased the degree of orientation. The direction of material transport between BNKT and PZT was important to obtain ceramics with a large degree of orientation. [source] Hydrothermal Synthesis of Tetragonal Barium Titanate from Barium Chloride and Titanium Tetrachloride under Moderate ConditionsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2002Huarui Xu Tetragonal BaTiO3powders were prepared hydrothermally at 240°C, in only 12 h, using BaCl2·2H2O and TiCl4, which are rather easy to manipulate. Characterization via X-ray diffractometry, scanning electron microscopy, Brunauer,Emmett,Teller analysis, and differential scanning calorimetry confirmed that increasing the NaOH excess concentration (from 0.5M to 2.0M) and decreasing the initial TiCl4concentration (from 0.625M to 0.15M) promotes the formation of tetragonal BaTiO3powders. After reaction, the powders were proved to be phase-pure BaTiO3, with no impurities, such as Cl, and CO32,. [source] Fabrication of Optically Transparent Lead Lanthanum Zirconate Titanate ((Pb,La)(Zr,Ti)O3) Ceramics by a Three-Stage-Atmosphere-Sintering TechniqueJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2002Yoshiyuki Abe An easy technique has been developed to fabricate optically transparent lanthanum-modified lead zirconate titanate (PLZT) ceramics. This technique consists of three stages: (1) sintering in an oxygen atmosphere, (2) elimination of pores in a carbon dioxide atmosphere, and (3) elimination of oxygen vacancies in an oxygen atmosphere. The carbon dioxide atmosphere enhances the diffusion of oxygen from the pores to outside the sintered body. The experimental results reveal that use of a carbon dioxide atmosphere effectively decreases residual pores and improves optical transmittance. From commercially available raw powders, an optical transmittance of 51% (wavelength of 550 nm) can be achieved for 0.7 mm thick polished PLZT9/65/35 ceramics using a carbon dioxide atmosphere, whereas the value is only 34% without a carbon dioxide atmosphere. The advantage of this technique is that PLZT ceramics having high optical quality can be obtained using conventional sintering tools. [source] Revisit to the Origin of Grain Growth Anomaly in Yttria-Doped Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2001Jung-Kun Lee In this study, the effect of atmosphere during calcining and sintering of Y2O3 -doped BaTiO3 was investigated to reveal the origin of the anomaly of grain growth and conductivity as a function of Y2O3 content. Samples with various atmospheric histories were prepared. Microstructural and electrical variations were observed using SEM, dielectric (,r vs T) and thermopower measuring techniques, and impedance spectroscopy. An abrupt decrease in grain growth and a transition from semiconducting to insulating behavior were observed when the Y2O3 concentration exceeded 0.3 mol% and the samples were heat-treated in an O2 atmosphere. In contrast, the samples treated under N2+ 5% H2 atmosphere revealed neither grain growth anomaly nor conductivity anomaly even though the Y2O3 concentration was much greater than 3 mol%. The undoped BaTiO3 samples also demonstrated increased average grain size with increased oxygen partial pressure. Therefore, it was suggested that the grain growth anomaly did not result from the formation of cation vacancies V,Ba or V,,Ti. To investigate the origin of the grain growth anomaly, the Curie temperature, concentration of free electrons, and impedance spectra were measured. The grain growth anomaly and conductivity anomaly were associated with abrupt changes in all the measurements. These abrupt changes could be explained by the partial incorporation of donor dopants. Consequently, the origin of the anomaly in the microstructure and electrical properties are discussed in terms of grain-boundary segregation of the donor dopant. [source] Positive Temperature Coefficient of Resistivity Effect in Highly Donor,Doped Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2001Darko Makovec BaTiO3 ceramics doped with different La concentrations (0,12 mol%) were prepared by sintering under the reducing conditions of a nitrogen atmosphere containing 1% hydrogen. The critical donor concentration that causes blocking of the exaggerated grain growth was observed to be ,10 mol% La. The samples, which were semiconducting after sintering under reducing conditions, were subsequently reoxidized by annealing in air to induce the positive temperature coefficient of resistivity (PTCR) effect. After reoxidation at 1150°C a noticeable PTCR effect was observed in the samples doped with La concentrations as high as 2.5 mol%. The room-temperature resistivity after reoxidation was found to increase with increasing donor concentration due to an increase in the thickness of the insulating layers at the grain boundaries. TEM analysis showed that reoxidation of the samples caused precipitation of the Ti-rich compound Ba6Ti17O40 inside the doped BaTiO3 -matrix grains. [source] Effect of Silver on the Sintering and Grain-Growth Behavior of Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2000Chin-Yi Chen Silver and its alloys frequently are used as electrode material for BaTiO3 -based dielectrics. In the present study, a small amount of fine silver particles have been intimately mixed with BaTiO3 powder. The sintering and grain-growth behavior of the silver-doped BaTiO3 in air are investigated. The solubility of silver in BaTiO3, as revealed by lattice-parameter measurement, electrical measurement, and electron probe microanalysis, is <300 ppm. The densification of BaTiO3 is slowed slightly by the addition of silver inclusions. However, the presence of a small amount (<0.3 wt%) of silver increases the amount and size of abnormal grains. When the silver content is >0.3 wt%, the grain growth of BaTiO3 then is prohibited by the silver inclusions. [source] Role of Length Scale on Pressure Increase and Yield of Poly(vinyl butyral),Barium Titanate,Platinum Multilayer Ceramic Capacitors during Binder BurnoutJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Leo C.-K. The binder-burnout kinetics of poly(vinyl) butyral from BaTiO3 multilayer ceramic capacitors with platinum metal electrodes were analyzed by combining thermogravimetric analysis with infrared spectroscopy. The rate of weight loss was accelerated when both BaTiO3 and platinum metal were present, and the presence of both metal and ceramic enhanced the production of CO2. The activation energy and pre-exponential factor were determined by analysis of the weight-loss data with a first-order kinetics model. Then, the decomposition kinetics were incorporated into a coupled heat- and mass-transport model to predict pressure increases as a function of the heating cycle. The heating cycles determined in this manner then were used to evaluate the yield of capacitors 1.3,3.8 cm long and 0.3,1.3 cm high. The optimum yield was realized at an aspect ratio (height:length) of 1:3. [source] Necessary Conditions for the Formation of {111} Twins in Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Byoung-Ki Lee The experimental conditions for {111} twin formation in BaTiO3 were investigated. When BaTiO3 compacts without excess TiO2 were sintered either in an oxidizing atmosphere (air) or in a reducing atmosphere (95N2,5H2), no {111} twins formed within the BaTiO3 grains and no abnormal grain growth occurred. In contrast, many {111} twins were present within the abnormally grown grains in the excess-TiO2 -containing BaTiO3 samples sintered in air, while no twins were observed in the excess-TiO2 -containing samples sintered in 95N2,5H2. X-ray diffraction analysis showed that excess TiO2 forms a Ba6Ti17O40 phase during sintering with the space group A2/a in air and a Ba6Ti17O40,x phase with the space group C in 95N2,5H2. It appears therefore that excess TiO2 and an oxidizing atmosphere are necessary for {111} twin formation in BaTiO3. These results may also indicate that the interface structure between BaTiO3 and Ba6Ti17O40 influences the twin formation. [source] Calcium- and Lanthanum-Modified Lead Titanate (PCLT) Ceramic and PCLT/Vinylidene Fluoride-Trifluoroethylene 0-3 NanocompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2000Q. Q. Zhang Calcium- and lanthanum-modified lead titanate (PCLT) powders with size in the nanometer range were prepared by a sol,gel process. The PCLT gel was annealed at 850°C to produce powder with an average particle diameter of 80 nm. A dense and fine-grained PCLT ceramic, with grain size of ,0.7 ,m, was prepared by sintering the sol,gel-derived powder at 1150°C. The piezoelectric and pyroelectric properties of the PCLT ceramic varied linearly with the degree of poling in the ceramic. PCLT/vinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) 0-3 nanocomposites with PCLT volume fractions of 0.1,0.5 were fabricated, using PCLT powders imbedded in a P(VDF-TrFE) matrix. The ceramic data were used to model the piezoelectric and pyroelectric properties of the PCLT/P(VDF-TrFE) composites, and good agreements were obtained. [source] Use of Titanates to Achieve a Temperature-Stable Low-Temperature Cofired Ceramic Dielectric for Wireless ApplicationsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2002Steve Xunhu Dai A low-loss and near-zero temperature coefficient of resonant frequency (Tf) low-temperature cofired ceramic (LTCC) host dielectric was developed for portable consumer wireless device applications. The low Tf was realized by compensating the Al2O3 -filled-glass dielectric with admixtures of TiO2 (negative temperature coefficient of dielectric constant (T,)) in the starting formulation. XRD data indicated a portion of the TiO2 in the starting formulation dissolved into the glass, and extensive formation of crystalline titanium compounds was observed via a nucleation and growth mechanism. The dissolution of TiO2 in the glass and subsequent formation of titanium compounds was believed to result in the relatively small amount of TiO2 required to achieve a near-zero Tf in the final sintered structure. [source] ChemInform Abstract: Enantioselective Conjugate Addition Employing 2-Heteroaryl Titanates and Zinc Reagents.CHEMINFORM, Issue 6 2010Anna J. Smith Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Structure Property Relationships in the ATi2O4 (A: Na, Ca) Family of Reduced Titanates.CHEMINFORM, Issue 1 2007Margret J. Geselbracht Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Flux growth of La-doped lead zirconate stannate titanate antiferroelectric crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2008Lin Wang Abstract Relaxor antiferroelectric single crystals lead lanthanum zirconate stannate titanate (PLZST) with the composition around the morphotropic phase boundary (MPB) have been grown by flux method using 50 wt% PbO-PbF2 -B2O3 as a flux. The obtained crystals are light yellow in color. The XRD patterns revealed that the habitual faces of the obtained crystal are (001). The crystal morphology was studied and related to a layer growth mechanism controlled by two-dimensional growth. The chemical composition of as-grown crystal was analyzed by inductively coupled plasma atomic emission spectrometry (ICP), indicating a slight decrease of the amount of Ti compared to the starting materials. The result was verified by the XRD patterns with the phase transformation from the co-existence of tetragonal and rhombohedra phases to the single tetragonal phase. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low-Temperature Synthesis of Phase-Pure 0D,1D BaTiO3 Nanostructures Using H2Ti3O7 TemplatesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2010Duk Kyu Lee Abstract One-dimensional (1D) barium titanate (BaTiO3) nanowires, which were uniformly covered with 0D BaTiO3 nanocrystals, were synthesized by using a simple solvothermal reaction of protonated trititanate (H2Ti3O7) nanowires with barium hydroxide octahydrate [Ba(OH)2·8H2O] at 80 °C in ethanol/water mixed solvent systems. The compositions of the mixed solvents , the volume ratio of ethanol to deionized water , was a key controlling parameter in order to determine the phase formation and primary particle size of the 0D BaTiO3 nanocrystals. Single-phase cubic perovskite BaTiO3 started to form at 80 °C in a mixed solvent containing more than approximately 60,% by volume of ethanol. Field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) analysis revealed that the as-prepared BaTiO3 retained its wire-shaped morphology with nanocrystals on the surface. Furthermore, the synthetic mechanism of the 0D-1D BaTiO3 nanostructures was demonstrated in view of the dielectric tuning of the mixed solvent and the similarities between the crystal structures of BaTiO3 and H2Ti3O7. [source] Potential Bioelectroactive Bone Regeneration Polymer Nanocomposites with High Dielectric Permittivity,ADVANCED ENGINEERING MATERIALS, Issue 10 2009Zhi-Min Dang The frequency dependence of the dielectric permittivity of (barium titanate,hydroxyapatite)/poly(vinylidene fluoride) three-phase nanocomposites is investigated at room temperature and different fractions of barium titanate. The permittivity increases with increasing concentration of barium titanate. A weak decrease in permittivity is also observed for frequencies below 106 Hz. The SEM image inset in a dielectric permittivity vs. frequency curve shows that rod-like hydroxyapatite and sphere-like barium titanate nanoparticles exist in the three-phase nanocomposites. [source] | ||||||||||||||||||||||||||||||||||