Search

Sb-modified lithium bismuth titanate Li0.5Bi0.3Sb0.2TiO3 is prepared following the mixed oxide method. The development of a new compound with a single-phase orthorhombic crystal structure is approved from the XRD analysis at environmental temperature. The electrical behavior like dielectric and electrical conductivity are analyzed in a wide temperature as well as frequency range by the impedance analyzer, which exhibits that these properties effectively depend on frequency and temperature. The ac conductivity versus temperatures plots obeys the Arrhenius relation and confirm the presence of the mixed type of conductivity process like space charge conductivity created from oxygen ion vacancies, ionic-polaronic conductivity, and so on, in the sample. Ac conductivity versus frequency spectra is as per Jonscher's Universal Power law. [ABSTRACT FROM AUTHOR]

Sb-modified alkali bismuth titanate Li0.5Bi0.5−xSbxTiO3 (x = 0 and 0.1) compounds are prepared using the method of solid-state-reaction route. The XRD exploration in environmental conditions confirms the development of new compounds having single-phase orthorhombic crystal structures. Non-uniformly distributed grains are noticed in SEM micrographs for both compounds. The electric & dielectric behavior is analyzed by use of an impedance analyzer. The exploration of the dielectric behaviors of both compounds in a wide frequency range (100 Hz–1 MHz) & temperature range (30–500 °C) suggests that these characteristics are strongly dependent on frequency & temperature. Activation energy assessed from temperature variation of ac-conductivity in various zones recommends that the electric transport phenomenon obeys the Arrhenius equation and shows a mixed type of conductivity. [ABSTRACT FROM AUTHOR]

In this paper, detailed studies of effect of small amount of manganese substitution (at the zirconium site) on the structural, micro-structural, and electrical characteristics of lead zirconate titanate of Pb(Zr0.35–xMnxTi0.65)O3;x = 0, 0.02, 0.06, 0.10 (PZMT)) have been reported. The materials were prepared by using standard ceramic technology. The formation of the compounds and their basic crystal data have been studied through X-ray diffraction (XRD) method. The crystallite size and lattice strain of the compounds, evaluated from Scherrer's and Hall Williamson (H-W) equations, is found to be in the range of 40–50 nm and 11 × 10−4 to 50 × 10−4, respectively. Microstructures of different magnifications, revealing the surface nature of the compounds, have been recorded by field emission scanning electron microscope (FESEM). Effect of Mn+4 ions on electrical behavior (electrical impedance (Z*), electrical modulus (M*), conduction and relaxation phenomenon) of PZMT systems, over wide range of temperature and frequency, has been studied. [ABSTRACT FROM AUTHOR]

The current communication addresses structural, impedance, conductivity, dielectric permittivity, tangent loss, and ferroelectric hysteresis of selenium doped bismuth titanate (Bi4Ti2.9Se0.1O12) synthesized by a solid-state reaction technique. XRD profile reveals the formation of orthorhombic unit cell structure (B2ab space group) in Bi4Ti2.9Se0.1O12. Partial doping of Se (10%) makes significant modifications in the electrical and dielectric characteristics, which are investigated over discrete frequencies (1 kHz–1 MHz) and temperatures (27–300 °C). The compound exhibits comparatively low value of the tangent loss at 1 MHz frequency. The ferroelectric hysteresis loop of the compound confirms the non-centrosymmetric arrangement of elements at room temperature, and the value of remanent polarization makes the compound suitable for memory applications. [ABSTRACT FROM AUTHOR]

The structural, dielectric and transport properties of modified Bismuth Sodium Titanate (BNT) are reported. Mn and Sr-modified BNT (Bi0.35Na0.35Sr0.3Ti0.9Mn0.1O3) was synthesized by a solid-state reaction route. Structural analysis based on Rietveld refinement of X-ray diffraction data confirms the single-phase characteristic without change of hexagonal crystal structure with R3C space group of BNT. The dielectric characteristics of the modified BNT are recorded in the frequency range of 20 Hz to 1 MHz at temperatures of 50 °C and 200 °C. Using the frequency-dependent, real and imaginary parts of the dielectric constant, ϵ′(ω)-ϵ″(ω) dipolar and hopping conduction-based carrier polarization properties are discussed. The dipole parameters such as relaxation time, static and high-frequency dielectric constant etc. are estimated by using Cole-Cole relaxation model. [ABSTRACT FROM AUTHOR]

This communication reports the effect of Iron (Fe) and Lithium (Li) co-doping on the structural, dielectric and electrical properties of Ba0.8Sr0.2TiO3; i.e. (Fe0.5Li0.5)0.1Ba0.7Sr0.2TiO3 (FLBST). The FLBST composite was synthesized by the solid-state mixed oxide method at 1400 °C for 12h. The crystalline phase formation has been confirmed by the X-ray diffraction technique and analyzed through the Rietveld Analysis using X'Pert Highscore plus software. From the XRD analysis, lattice parameters and the average crystallite size was calculated. The electrical properties of sintered (at 1450 °C for 2h) pellets were carried out in the temperature range of 30 °C–350 °C using impedance spectroscopy. Based on the real and imaginary part of the dielectric constant, i) the dipolar contribution which is dominant in 30 °C–150 °C is characterized by Curie-Weiss law and ii) contribution from defects and oxygen vacancies seen beyond 150 °C is described by Arrhenius equation. [ABSTRACT FROM AUTHOR]

The current communication addresses structural, impedance, conductivity, dielectric permittivity, tangent loss, and ferroelectric hysteresis of selenium doped bismuth titanate (Bi4Ti2.9Se0.1O12) synthesized by a solid-state reaction technique. XRD profile reveals the formation of orthorhombic unit cell structure (B2ab space group) in Bi4Ti2.9Se0.1O12. Partial doping of Se (10%) makes significant modifications in the electrical and dielectric characteristics, which are investigated over discrete frequencies (1 kHz–1 MHz) and temperatures (27–300 °C). The compound exhibits comparatively low value of the tangent loss at 1 MHz frequency. The ferroelectric hysteresis loop of the compound confirms the non-centrosymmetric arrangement of elements at room temperature, and the value of remanent polarization makes the compound suitable for memory applications. [ABSTRACT FROM AUTHOR]

Crystal structure and Dielectric properties investigation of lead-free Bi0.35Na0.25Li0.1Sr0.3TiO3 (BNLST) composite is reported. The required solid solution was synthesized using oxides and carbonates via the solid-state reaction method. The stoichiometrically weighed and mixed powder was calcined at 800 °C for 12 h, and the pellets were sintered at 1250 °C for 2 h. XRD measurements confirm the formation of single-phase rhombohedral perovskite structure and the crystal structure was refined using the X'Pert High-score plus software. The full-width half maxima of the XRD peak was used to compute the average crystallite size employing the Debye-Scherrer, Williamson-Hall, and Halder-Wagner techniques. The BNLST's dielectric measurements were performed as a function of temperature at five distinct frequencies in the range of 100 Hz–1 MHz. The phase transition temperatures are shifted toward room temperature with the doping of Li and Sr. The diffuseness parameters of the phase transition, the a.c. electrical conductivity and the activation energy are estimated for the BNLST composite. [ABSTRACT FROM AUTHOR]

In the present work, pure and bismuth-doped barium titanates have been prepared using the sol-gel method. The chemical formula used for the synthesis of bi-doped barium titanate is Ba1-xBixTiO3, where the values of x have been chosen to be 0.00, 0.05, 0.075, 0.10, and 0.15. Barium acetate [Ba(CH3COO)2] and titanium (IV) isopropoxide [Ti{OCH(CH3)2}4] have been used as barium and titanium precursors, respectively. For bismuth doping, bismuth (III) nitrate pentahydrate [Bi(NO3)3)5H2O] has been used. The paper discusses the preparation mechanism, tolerance factor, and the thermal characterization (TGA/DSC) results of pure and bi-doped barium titanate ceramics. [ABSTRACT FROM AUTHOR]

The structural and dielectric properties of magnesium titanate solid solutions substituted with zinc or cobalt (MxMg1-x) TiO3 (M=Zn/Co and x=0.00, 0.05) were investigated. MgTiO3 formed as a single phase, according to X-ray diffraction analysis. Low porosity, tightly packed grains were detected using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses. The dielectric properties reveal that (MxMg1-x) TiO3 with Zn = 0.05 shows a good combination of relative permittivity (ɛr) of 15.10, loss tangent (tan) of 1.11×10-3, and temperature coefficient of resonant frequency (τf) of -42.70ppm/°C at 1MHz was reported. [ABSTRACT FROM AUTHOR]

In order to realize the preparation of environmentally friendly piezoelectric ceramic coatings on the surface of metallic materials, sodium bismuth titanate (Bi0.5Na0.5TiO3, BNT) ceramic coatings were prepared by supersonic plasma spraying. The surface morphology, cross-sectional morphology, phase structure, and elemental valence variations of the BNT coating were examined, as well as the dielectric and ferroelectric properties of the BNT coating. The results show that the coating has a good quality and a single perovskite structure. The dielectric constant was stable at about 425 and the dielectric loss was stable at about 0.06 when the test frequency reached 200 kHz. The coating exhibits good hysteresis lines under different applied electric fields. When the applied electric field was 40 kV/cm, the remnant polarization value of the prepared coating was 11.47 mC/cm². It can be seen that the BNT piezoelectric coating prepared by supersonic plasma spraying has good ferroelectric and dielectric properties, which lays a solid foundation for in-situ monitoring of environmentally friendly lead-free BNT piezoelectric coating. [ABSTRACT FROM AUTHOR]

Lead-free ceramics based on bismuth sodium lanthanum titanate (Bi0.4871Na0.4871La0.0172TiO3: BNLT) and barium titanate (BaTiO3: BT) were prepared by a modified two-step mixed-oxide method. Effects of BT content on the phase transition, thermal expansion behavior, mechanical and electrical properties of lead-free BNLT-BT ceramics were studied. The Burn's temperature and local polarizations were estimated from the thermal expansion data. Various aspects of understanding the polarization behavior and other effects in this system have also been investigated and discussed. The 0.96BNLT-0.04BT ceramics have shown the d33 value of 135 pC/N. The coercive field (Ec) and remanent polarization (Pr) were found to be 24 kV/cm and 9.0 µC/cm2, respectively. This may be useful in the future development of multifunctional lead-free materials in electronic applications. [ABSTRACT FROM AUTHOR]

This study focused on the rare-earth hetero-valent substituted perovskite BaMO3 (M = Ce, Pr and Tb) which expected to show magnetoelectric response. In general, diamagnetic feature is presented in the 4f0 BaCeO3 system down to 2 K which is chosen as a reference in the study while BaPrO3 (4f1) and BaTbO3 (4f7) display antiferromagnetic phase transition at TN = 11.7 and 33.2 K, respectively, measured by MPMS magnetometer. At high oxygen partial pressure and donor ion-substitution (Nb5+), the BaMO3 systems demonstrate a similar defect chemistry to titanate perovskite which compensated by Ba-vacancy. Dielectric relaxation is detected for the doublet (BaPrO3 and BaTbO3) at the antiferromagnetic phase transition region. In order to examine the magnetoelectric response, the 8 Tesla of magnetic field is applied to the samples during the dielectric measurement. BaTbO3 shows a modest magnetoelectric response around 0.2% at the antiferromagnetic phase transition while that of BaPrO3 is silent. The activation energies derived from Arrhenius equation are reported to be in the range of 0.2 − 0.6 eV. [ABSTRACT FROM AUTHOR]

A composite of bacterial cellulose and titanate nanotubes (BC/TNT) was prepared for use as a stretchable motion sensor in smart and wearable electronics. The composite was characterized using various techniques such as UV-VIS-NIR spectroscopy, SEM, XRD, IR spectroscopy, and thermogravimetric analysis. It was found that the dielectric constant of BC/TNT was up to 2.6 times that of BC with similar loss tangent, indicating improved charge storage. The composite was also constructed into a Kirigami pattern for improved stretchability. With a tensile strain of 0.4%, the change in resistance relative to the original resistance (ΔR/R0) was found to be 5.7% and 6.9% for BC and BC/TNT, respectively, demonstrating improved sensing performance. [ABSTRACT FROM AUTHOR]

This work presents the impact generated energy harvesting characteristics of cement/lead zirconate titanate (Pb(Zr0.52Ti0.48)O3; PZT) composites. A soft grade PZT (SP 5 A) with ∼1 µm sized particles in an unpoled state was utilised to prepare cement/PZT composites. The experiments were performed on 28 days' water cured unpoled samples. The total cumulative volume and average pore radius are observed to decrease with PZT concentration in the composite. The values of piezoelectric coefficient and capacitance were, respectively, found to increase by 300 and 275% for cement/PZT composites consisting of 40% PZT compared to that of 5% added PZT. The impact generated voltage and energy increases significantly with increasing PZT-content. The voltage generation from cement/PZT could be because of the oscillations of dipoles and the mobility of ions in the pores of the hydrated cement. The results obtained foreshadow the prospect of utilising cement/PZT composites for energy harvesting from civil structures, structural health monitoring, and as sensors. [ABSTRACT FROM AUTHOR]

Calcium Copper Titanium Oxide (CCTO) Ceramics of composition CaCu3Ti4O12 has emerged as a lead-free ceramic supercapacitor with a large dielectric constant of 104–105 at room temperature. The CCTO microstructure is electrically heterogeneous composed of semiconducting grains and insulating grain boundaries. The origin of the large dielectric constant has therefore been widely attributed to barrier layer capacitance originated at grain boundaries. Our research is focused on understanding the stability and reproducibility of the measured electrical and dielectric properties when they are used as capacitor dielectrics because of the inconsistent results obtained when tested in ambient conditions. The origin of this inconsistency is investigated through the roles of testing atmosphere, sample thickness and doping with alumina on the stability and reproducibility of dielectric properties of CCTO. The solid state reaction method is used to fabricate phase pure and dense samples. AC impedance spectroscopy is used to study the roles of testing atmospheres, temperatures, microstructures, grain boundaries, sample thickness, alumina doping and frequency on the dielectric properties. It is shown that this approach of characterizing fundamental electrical properties of CCTO can be used to eliminate hysteresis to produce stable and reproducible dielectric properties. These perspectives are presented and discussed. [ABSTRACT FROM AUTHOR]

lithium titanate (LTO), which has spinel structure, has become one of the most popular anode materials for lithium-ion batteries because of its high safety and stability. In this paper, industrial metatitanic acid and lithium hydroxide were used as the main raw materials to prepare nanotube LTO materials by two-step hydrothermal method. The effects of different titanium sources, stirring speed, hydrothermal reaction temperature and time, li-ti molar ratio and other process parameters on the phase, morphology and electrochemical properties of the samples were studied. The experimental results show that the nanotube LTO electrode material can be prepared by stirring at 300 rpm, reacting at a hydrothermal temperature of 170 °C for 20h, controlling the lithium titanium molar ratio of 0.85, and finally calcining; The specific capacity of nanotube LTO reaches 150mah/g at 10 C high magnification, and the capacity retention rate of 500 cycles is more than 92%. Compared with ordinary LTO materials, nanotube LTO has obvious performance advantages and excellent comprehensive electrochemical performance. [ABSTRACT FROM AUTHOR]

Manganese is naturally present in water, but its increased concentration in potable water is undesirable for multiple reasons. This study investigates an alternative method of demanganization by a newly synthesized TiO2-based adsorbent prepared through the transformation of titanyl sulphate monohydrate to amorphous sodium titanate. Its adsorption capacity for Mn2+ was determined, while a range of influential factors, such as the effect of contact time, adsorbent dosage, pH value, and added ions was evaluated. The adsorbent appeared highly effective for Mn2+ removal owing to its unique characteristics. Besides adsorption via electrostatic interactions, ion-exchange was also involved in the Mn2+ removal. Although the Mn2+ removal occurred within the whole investigated pH range of 4–8, the maximum was achieved at pH 7, with qe = 73.83 mg g-1. Equilibrium data revealed a good correlation with Langmuir isotherm in the absence of any ions or in the presence of monovalent co-existing ions, while the results in the presence of divalent co-existing ions showed a better fit to Freundlich isotherm. Additionally, the presence of monovalent cations (Na+, K+) only slightly decreased the Mn2+ removal efficiency as compared to divalent cations (Ca2+, Mg2+) that caused a greater decrease; however, the effect of anions (Cl-, SO42-) was insignificant. To provide insight into the adsorbent safety, the toxicity assessment was performed and showed no harmful effect on cell activity. Furthermore, the residual concentration of titanium after adsorption was always below the detection limit. The results imply that the synthesized TiO2-based adsorbent is a safe promising alternative method for demanganization. Highlights The synthesis of amorphous TiO2-based adsorbent was presented. The TiO2-based adsorbent was found to be efficient for Mn2+ removal. The Mn2+ removal mechanisms were adsorption and ion-exchange. Increasing pH enhanced the efficiency of Mn2+ removal. Divalent cations decreased the Mn2+ removal efficiency more than monovalent cations. [ABSTRACT FROM AUTHOR]

A lepidocrocite-like potassium titanate, (Kx(LixTi1-x)O2; Lss) with a layered structure can provide a reactive interlayer space for soft-chemical reaction such as ion-exchange or intercalation and the hydrated sodium derivative (Lss-Na) was obtained by an ion-exchange reaction. The crystal structures of the hydrated and dehydrated Lss-Na were refined by using synchrotron powder X-ray diffraction data. Two steps of dehydrated processes for the Lss-Na were observed by in-situ synchrotron powder X-ray diffraction. The ion-exchange property for Lss-Na was superior to those for Lss and Lss-H and was corelated with the effective basal space which was expanded by formation of two layers of water molecules. [ABSTRACT FROM AUTHOR]

Influence of (K0.5Bi0.5)TiO3 (KBT) dopants on crystal and microstructure, ferroelectric and dielectric properties of ceramic composition from morphotropic phase boundary in the system (1–x–y)(Na0.5Bi0.5)TiO3 – xBaTiO3 – y(K0.5Bi0.5)TiO3 (x = 0.06, y = 0–0.15) additionally modified by ZnO additives was studied using a complex of methods. Changes from 42.8 nm to 62.6 nm of the volume-weighted crystallite size distribution function G(L) corresponding to coherent scattering regions were observed. The microstructure and the second harmonic generation data indicated a change in the relative content of polar nanoregions in tetragonal nonpolar matrix. Decrease in temperatures of phase transitions Tm and Td was observed with KBT concentration increasing. [ABSTRACT FROM AUTHOR]

Ferroelectric thin films of lead titanate (PbTiO3) have been prepared on SiO2/Si(100) and LaNiO3(110)/SiO2/Si(100) substrates by a sol-gel spin coating method, using lead acetate trihydrate, and titanium isopropoxide as precursors along with 2-methoxyethanol as a solvent and acetic acid as catalyst. X-Ray Diffraction patterns show the formation of the perovskites structure of PbTiO3 thin films deposited on SiO2/Si substrates at 650°C. A SEM micrograph of the film cross-section is used to measure the thickness, which gave a value of 0.65 μm. Analysis of its ferroelectric hysteresis measurements gave values of remanent polarisation of Pr = 18.37 μC/cm2 and a coercive field of Ec = 121.53 kV/cm which are essential for non-volatile memories application. The current-voltage characteristic was found to be space charge conduction in the high voltage region and its piezoelectric coefficient d33, as measured by a Laser Scanning Doppler vibrometry, showed small linear decreases from 75 pm/V at 45 kV/cm to 67 pm/V at the highest applied field (330 kV/cm). [ABSTRACT FROM AUTHOR]

Based upon the density functional theory with generalised gradient approximation and ultra-soft pseudo-potential, first-principles calculations investigate the structural, electronic, and optical properties of nitrogen-doped PbTiO3. The computed results show that after nitrogen doping, the structure of PbTiO3 changes from cubic to pseudo-cubic tetragonal. Furthermore in an electronic perspective, we observe a significant reduction in the band gap (1.66 eV–0.56 eV) upon dopant incorporation and the band gap shifts from indirect to direct. For a detailed analysis of doping effects, the density of states, the partial density of states and elemental partial density of states are computed for pure and nitrogen-doped PbTiO3, which exhibit the strong coupling of O-2p-states with Ti-3d-states. Moreover, optical properties, such as the real and imaginary parts of the dielectric function, refractive index, reflection, absorption, energy loss function, and extinction coefficient for pure and doped lead titanate, have also been evaluated. The shifting of absorption edge towards lower energy values makes the nitrogen-doped lead titanate an attractive option for in optoelectronic frameworks. [ABSTRACT FROM AUTHOR]

In this paper, we focused on the green synthesis of titanium dioxide (TiO2) nanoparticles via an ecofriendly process using Citrus limon extract. Several analytical techniques were used to characterize the prepared samples: X-ray diffraction (XRD), infrared spectroscopy, Raman spectroscopy, Scanning Electron Microscopy (SEM) and X-ray photoelectrons spectroscopy (XPS). XRD diffractograms revealed an anatase crystal structure of TiO2. SEM analysis showed the presence of particles with nanometric sizes, and the Fourier transform infrared (FTIR) spectra confirmed the presence of the synthesized nanoparticles. The antibacterial activity of the green prepared TiO2 nanoparticles was assessed. Additionally, the antibacterial efficiency of the green prepared TiO2 nanoparticles was compared with TiO2 nanoparticles prepared via a chemical process. The results prove the efficacy of this ecofriendly process. This method can be used for the rapid and environmentally friendly biosynthesis of stable titanium oxide nanoparticles. This work is a contribution to the valorization of bio-sources for the synthesis of titanium dioxide crystals using Citrus limon fruit extract and tetrabutile titanate as a precursor. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT, P b Z r 1 − x T i x O 3 ) is a piezoelectric ceramic which can be used for several applications such as actuators, sensors, and microelectronic devices. Depending on its composition, PZT can exhibit rhombohedral, orthorhombic (tetragonal) phases, with the piezoelectric charge constant ( e i j ) key to evaluating its piezoelectric properties. In this study, ( e i j ) was calculated using density functional perturbation theory (DFPT) based on first-principles methods. First, we reveal that the rhombohedral structure is stable for Zr-rich compositions. Second, extending the study to P b Z r 0.56 T i 0.44 O 3 and P b 0.94 S r 0.06 Z r 0.56 T i 0.44 O 3 (PSZT), we evaluated the values of e i j both theoretically and experimentally to investigate how they are affected by doping. The microscopic movements of individual atoms within the optimized crystal were analyzed to investigate the correlations between the structural characteristics and e i j . The results show that the relative positions of Ti and Zr (B-site) atoms and the quadratic elongation in the PZT octahedron depend strongly on the piezoelectric charge constant e 33 , which itself depends on the Ti content. The local atomic structural parameters described in this study can be used as a descriptor for the high-throughput screening of PZT materials. [ABSTRACT FROM AUTHOR]

Titanate nanotubes (NTs) were synthesised by the hydrothermal method and later calcined at temperatures between 100–500°C. The calcined NTs were characterised and evaluated in the physicochemical adsorption of the safranin dye and photocatalytic degradation of caffeine. The materials calcined at low temperatures displayed a tubular structure and the H2Ti3O7 crystalline phase, which was transformed into anatase nanoparticles at 400°C. The NTs treated at 100°C showed the highest adsorption capacity (94%). Safranin was adsorbed through an ion-exchange mechanism, following the Langmuir isotherm and a pseudo-second-order kinetic model. While NTs calcined at lower temperatures were better for adsorption, the photocatalytic degradation of caffeine increased in samples calcined at higher temperatures with a maximum removal of 72%. The photocatalytic behaviour of the NT samples confirmed that the crystalline anatase structure in conjunction with structural OH groups enhanced the photocatalytic activity. The addition of isopropanol as a scavenger confirmed the important role played by the •OH radicals in the photocatalytic process. NTs calcined at 300°C were efficient for both adsorption and photocatalytic processes. Due to its efficiency, this sample was reused after dye adsorption for the photocatalytic degradation of caffeine under visible light due to its enhanced absorbance in the visible region. This research work shows the potential of NTs for wastewater purification. [ABSTRACT FROM AUTHOR]

Influence of dopants on structure, microstructure, dielectric and ferroelectric properties of ferroelectric-relaxor (Na0.5Bi0.5)TiO3 ceramics modified by Ba2+ cations and overstoichiometric additives (SiO2 and Na2O) was studied. Changes in structure, microstructure, and dielectric parameters were observed depending on solid solutions compositions. [ABSTRACT FROM AUTHOR]

Thin polycrystalline lead zirconate titanate (PZT) films with a Zr:Ti ratio close to morphotropic phase boundary were obtained by radiofrequency sputtering at a temperature of 540 °C on a metal substrate, and their structural and electrophysical properties were studied. The piezoelectric coefficient, remnant polarization, coercive field, and dielectric constant of the PZT film are 3.84 μC/cm2, 1.20 ÷ 1.26 μC/cm2, 1.1 ÷ 1.3·105 V/cm, and 145, respectively. Domains of the perovskite phase are located on the surface of the film protrusions. The magnitude of the piezoelectric modulus of the domain is 17.9 ÷ 22.4 pC/V. [ABSTRACT FROM AUTHOR]

Phase transitions in PbZrO3 (PZ), PbTiO3 (PT), and solid solutions of Pb(Zr1-xTix)O3 system were studied by dilatometric method. The temperature dependence of thermal expansion and linear coefficient of thermal expansion for both single crystals and ceramic samples exhibit several anomalies corresponding to phase transitions of different origin and correlate to the results of X-ray diffraction studies. The obtained results should be taken into account for development of materials and devices based on the studied solid solutions of Pb(Zr1-xTix)O3 system. [ABSTRACT FROM AUTHOR]

The effect of pressure of pelletisation on the density, microstructure, dielectric, ferroelectric, piezoelectric and energy storage density of B-site Zr doped barium titanate has been studied. X-ray diffraction confirmed that zirconium form complete solid solution with barium titanate. It has been observed that 4 ton/cm2 is an optimum pressure of pelletisation which gives maximum density, maximum dielectric constant, maximum piezoelectric constant and high energy storage density with efficiency of 67.68%. There is a good correlation among the density, grain size, dielectric, ferroelectric and piezoelectric properties. These results suggest that this material has a potential for energy storage applications. [ABSTRACT FROM AUTHOR]

In this work, the layered structure of lepidocrocite-type alkali titanates was modified via the vibratory milling technique. The Cs2Ti6O13, Cs0.7Zn0.35Ti1.65O4 and K0.8Zn0.4Ti1.6O4 systems were prepared by calcining the mixed oxide/(hydrogen)carbonate at 800 °C for 20 h with a heating rate of 10 °C/min and a cooling rate of 20 °C/min. After that, these powders were re-milled by vibratory milling for various times in order to study the effect of post-synthetic mechanical milling to structural modification and interlayer spacing. The phase formation of all powders was determined by using X-ray diffractometer (XRD). Lattice parameters and interlayer spacing of all samples were calculated from XRD peaks. The results showed that the single-phase of lepidocrocite-type Cs2Ti6O13 and Cs0.7Zn0.35Ti1.65O4 was maintained after milling, and the interlayer distance increased by 0.5%. Meanwhile, a mixture of expanded- and original one was observed for K0.8Zn0.4Ti1.6O4, with the interlayer expansion up to 1.4%. When compared three systems together which had different interlayer ions and alkali-to-titanium ratio, it was found that the interlayer distances of the Cs2Ti6O13 (Cs/Ti = 0.33) and Cs0.7Zn0.35Ti1.65O4 (Cs/Ti = 0.42) systems were not different because the relatively large Cs ion placed itself at the interlayer position. For the K0.8Zn0.4Ti1.6O4 system (K/Ti = 0.50), the interlayer distance was much lower than those of the Cs2Ti6O13 and Cs0.7Zn0.35Ti1.65O4 because of the smaller K ion. [ABSTRACT FROM AUTHOR]

The experimental and simulation of dielectric, AC resistivity and dielectric resonance and anti-resonance data on (Na0.5Bi0.5)(NdxTi1-2xNbx)O3] ceramics were carried out using modified Lorentz equations as proposed by us instead of well know and generally applied laws like Arrhenius law and formulas on piezoelectricity to obtain activation energy, relaxation time, piezoelectric charge constant and voltage constant directly from the experimental data. The piezoelectric charge constant (d33) evaluated from the modeling are 864.64 p.m/V and 122.40 p.m/V; whereas the piezoelectric voltage constant (g33) are 10.88 p.m2/C and 8.55 p.m2/C for x = 0.0125 and 0.025 ceramic samples, respectively. [ABSTRACT FROM AUTHOR]

The in situ detection of the damaged aluminum alloy plate with bolted patch is numerically and experimentally studied based on a surface-mounted piezoelectric ceramic lead zirconate titanate (PZT) elements. The contact effects between the bolts, repair patch and host structure are considered. The convergence analysis, range-frequency analysis and pretension force analysis are discussed. The numerical results are good agreement with those of the experiments. The damage identification indexes are introduced for damage detection. It indicates the numerical simulation is effective for the damage deterioration of bolted repaired structures. The location of the PZT transducer is discussed to optimize the process. [ABSTRACT FROM AUTHOR]

N-doped TiO2 (N-TiO2) photocatalyst was prepared by the sol-gel method, using butyl titanate and urea as raw materials, and then loaded onto diatomite to prepare a composite photocatalyst. Bleached sulfate softwood pulp fiber was dissolved and mixed with the composite photocatalyst and then regenerated to prepare composite fillers for the manufacture of visible light-responsive photocatalytic paper suitable for the removal of toxic formaldehyde gas. Photocatalytic paper containing 20% composite filler with a ratio of 4/6 N-TiO2 (60% N-doping)/diatomite had good photocatalytic activity, with 50.1% formaldehyde degraded after 10 h under visible light irradiation. This photocatalytic paper also had good physical properties, with a paper density of 0.36 g cm−3, a burst index of 3.0 kPa·m2 g−1 and a tensile index of 43.33 Nm g−1, indicating that it has good prospects for removal of indoor air pollutants. [ABSTRACT FROM AUTHOR]

The evolution of device miniaturization and the potential application for next-generation nonvolatile memory devices Pb(Zr0.53Ti0.47)0.60(Fe0.5Ta0.5)0.40O3 (PZTFT) can be used as a barrier in multiferroic tunnel junctions. We report single-phase magnetoelectric multiferroic ultra-thin PZTFT at room temperature. The magnetic and ferroelectric properties have been investigated down to 7 nm thickness which are requisite properties for multiferroic tunnel barriers for multi-states memory applications. In the present study, we show that it remains a switching multiferroic at room temperature down to at least thickness d = 7 nm, which is thin enough for tunnel junctions. [ABSTRACT FROM AUTHOR]

Herein, we present the structural and electrical properties of layered titanate, the precursor of an ideal two-dimensional (2D) nanosheet. A K0.8Ti1.73Li0.27O4 (KTLO) sample was synthesized by the flux method to maximize the area of the, relative to that under conventional methods, and to assess the oriented growth direction of the synthesis process. The structure of the protonated layered titanate H1.07Ti1.73O4 (HTO), obtained by replacing the intercalated K+ cations with H3O+, was analyzed to observe the effect of variables in the acid exchange process. Notably, the electrical characteristics of both layered titanates in the bulk state have not been previously reported. Herein, we measured the dielectric permittivity of bulk layered titanates without thermal treatment, which was observed to be lower than that of the nanosheet form. Additionally, these titanates were successfully exfoliated into large single-layer nanosheets. Overall, these results provide insights to clarify the properties of layered materials prior to nanosheet exfoliation. [ABSTRACT FROM AUTHOR]

In the present work, two titanium precursors, titanium tetraisopropanolate (TTIP) and tetrabutyl titanate (TBOT), have been used to prepare titanium-based hybrid coatings by sol–gel method, with glycidyl ether oxypropyl trimethoxysilane (GPTMS) as the coupling reagent. The prepared hybrid coating materials are characterized by Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction analysis (PXRD), and thermogravimetric (TG) analysis. The morphology of the coating has been studied by scanning electron microscope (SEM). The corrosion protection of the hybrid coatings in 3.5 wt% sodium chloride medium are studied by the electrochemical impedance spectroscopy (EIS) and polarization method, and the results show that the hybrid coatings show corrosion protection of Cu substrates in aqueous 3.5% NaCl medium with a maximum corrosion inhibition efficiency of 88.9% achieved. [ABSTRACT FROM AUTHOR]

To expedite vitrification of low activity waste at the Hanford Site, a Tank-Side Cesium Removal system, using crystalline silicotitanate (CST) as the ion exchange media, is being evaluated. Laboratory scale testing of Cs removal by CST from Hanford tank waste supernates has been conducted by Pacific Northwest National Laboratory. Selectivity and partitioning of analytes on spent CST, specifically RCRA hazardous metals, selected +2 cations, and transuranic elements, were characterized through the complete digestion of CST. The CST was shown to adsorb a relevant fraction of Ca, Cd, Pb, Sr, U, Pu, Np, Am, and potentially Fe by IX and/or other mechanisms. [ABSTRACT FROM AUTHOR]

TiO2 precursor has been synthesized by sol-solvothermal method with tetrabutyl titanate as raw material. Nitrogen-modified TiO2 with different reaction temperatures (150, 180, 200 °C) was successfully fabricated by a facile hydrothermal method using hydrazine hydrate as nitrogen source. The as-prepared catalyst were conducted a series of tests and the analysis results indicated that nitrogen is successfully doped in the TiO2 lattice and exists in the form of interstitial doping and substitution doping. Furthermore, nitrogen-modified TiO2 enhanced the photocatalytic performance for methylene orange degradation and the degradation percentage of nitrogen modified TiO2 about reached 98%, which is higher than pure TiO2 and P25. The enhanced photocatalytic performance is ascribed to the larger specific surface area, smaller band gap and the existence of Ti3+. A possible photocatalytic mechanism was proposed. Furthermore, the results also indicated that the nitrogen-modified TiO2 prepared at a reaction temperature of 180 °C has excellent photocatalytic performance. [ABSTRACT FROM AUTHOR]

The effect of substitution of lithium cations in the sublattice A of sodium bismuth titanate on the parameters of the crystal structure, microstructure, dielectric and local piezoelectric properties of ceramics [(Na0.5Bi0.5)1-xLix] TiO3 with x = 0 ÷ 0.1 has been studied. Modified samples have been characterized by phase transitions manifesting themselves in the form of peaks of permittivity near ∼600 K. An increase in the value of the piezoelectric coefficient d33 at x ≥ 0.08 has been established, which correlates with an increase in the value of dielectric permittivity at room temperature. [ABSTRACT FROM AUTHOR]

Bi4 –xLaxTi3O12 (BiLT, x = 0.60–1.00) ceramics have been successfully synthesized by the alternative mechanochemical method and investigated their structural, microstructure, dielectric, and ferroelectric properties. Based on thermal stability of synthesized samples, compounds were calcined at 750 °C. No secondary phase is observed in the powder X-ray diffraction patterns. Plate-like shape with enhanced density is seen in the scanning electron microscope micrographs. EDAX pattern confirmed the chemical composition of samples. Prepared ceramic sample had relatively appreciable remanent polarization value (≈14.5 µC/cm2) at room temperature. Microstructure significantly influenced the dielectric and ferroelectric properties of the modified BiT ceramics. Synthesized compounds explored desirable electronic properties for innovative ferroelectric-based device applications. [ABSTRACT FROM AUTHOR]

Results of calorimetric and dielectric studies of ferroelectric composite (C6H16NBr)1-x/(PbTiO3)x (x = 0.1, 0.2, 0.3) are presented. It was shown that addition of lead titanate leads to a change of the sequence in structural phase transitions in diisipropylammonium bromide. In the temperature range 423–411 K, two phases of C6H16NBr (ferroelectric P21 and non-ferroelectric P212121) are coexist. It was found that their ratio depends on the lead titanate content. [ABSTRACT FROM AUTHOR]

We report the effect of various Bi:Ti ratios x:1 (x = 0.5–3) on the phase formation of sodium-bismuth titanate Na0.5Bi0.5TiO3 (NBT) during hydrothermal synthesis (230°С, 3 MPa, 96 h) from titanium oxide and bismuth hydroxide in 20 M NaOH solution. It was shown that single-phase ceramics with perovskite structure could be obtained at x = 0.5–0.9 using the hot-pressing technique (1025°С, 60 MPa, 1 h). At x = 1, hydrothermal synthesis results in single-phase samples, while, after sintering, the admixture of Na2Ti3O7 was detected. At x = 2 and 3, samples contained admixtures after hydrothermal synthesis. The x–value does not significantly affect the composition of perovskite-like products despite the excess of bismuth in the system. The chemical composition of the samples with x = 0.5–0.9 corresponds to the general formula Na0.60–0.69Bi0.40–0.31TiO2.9–2.81δ0.10–0.19 (where δ represents vacancies in oxygen sublattice). The Bi3+ content in the samples is underestimated due to the solubility of its hydroxide in a 20 M alkali solution. The properties of ceramics are not significantly affected by x values, and materials exhibit following average characteristics: electrical resistivity 1.3 × 109 Ohm∙cm, tanδ = 0.15, Кр = 0.1, d31 = 6.7 and d33 = 9.5 pC/N, g31 = 2.34 and g33 = 3 mV∙m/N. [ABSTRACT FROM AUTHOR]

We report a simple methodology for the preparation of an efficient visible-light responsive TiO2 photocatalyst through acid treatment of a lepidocrocite-type layered nickel cesium titanate (Cs0.7Ti1.65Ni0.35O4) for interlayer protonation and subsequent calcination at different temperatures (400–600°C) to induce structural transformation. The Ni-doped anatase/rutile nanocomposite possessing a morphology similar to that of protonated layered nickel titanate is obtained at all calcination temperatures. The sample obtained at 600°C exhibits the highest visible-light responsive photocatalytic activity for decomposition of the aqueous methylene blue dye under visible-light (λ > 420 nm) irradiation. The activity is 14 times higher than that of P25 (standard TiO2 photocatalyst) modified with Ni2+ and 3 times higher than that of NiTiO3 (visible-light responsive photocatalyst). The efficient visible-light responsive photocatalytic activity is ascribable to the visible-light absorption ability of the TiO2 phase owing to Ni-doping. Also, an efficient electron transfer across anatase–rutile interfaces for inhibition of charge recombination could be responsible for the activity. This methodology is a new route for efficient visible-light responsive photocatalysts based on TiO2 doped with various elemental species. This is because lepidocrocite-type layered titanates are available in a variety of chemical compositions. [ABSTRACT FROM AUTHOR]

The present study briefs the structural and optical properties of Gd doped BaZr0.05Ti0.95O3 ceramic synthesized via solid-state reaction (SSR) technique. The X-Ray diffraction (XRD) study reveals the formation of single phase of Gd modified BaZr0.05Ti0.95O3 ceramic. The Fourier transform infrared (FTIR) spectra are also presented in support of structural properties. The optical band-gap obtained from the UV-visible study, decreases with an increase in the Gd content. The photoluminescence study shows a broad hump around 560 nm. The studied compositions reveal the major contribution of shallow holes as compared to deep holes within the band-gap. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric bismuth sodium titanate (Bi0.5Na0.5)TiO3 (BNT) ceramics were prepared by quenching and the correlation among a depolarization temperature Td, the mechanical strength, and their piezoelectric properties were investigated. We controlled the quenching rate in the temperature range from 1100°C to 800°C. We examined the 5 patterns of the quenching rate (QR): 0.05 (ordinary firing, OF), 3.85, 5.77, 6.67, and 15.0 (quenching) oC/s. Td of the rapid quenched sample reached 229°C (QR = 15.0), but its mechanical strength decreased to a quarter of that of the OF ceramics. On the other hand, Td was 211°C at QR = 3.85 which was higher than that of OF-ceramic (QR = 0.05) at about 180°C. Moreover, three-point bending strength (227 MPa) of the quenched BNLT4 (QR = 3.85) was equivalent to that of the OF ceramics (235 MPa). Therefore, both Td and the mechanical strength were improved by controlling the quenching rate. [ABSTRACT FROM AUTHOR]

At the isothermal annealing below the crystallization temperature, dependences of the internal friction on time for the thin-film nanogranular composite consisting of crystalline nickel (Ni) and an amorphous material based on lead zirconate titanate [Pb0.81Sr0.04(Na0.5Bi0.5)0.15][(Zr0.575Ti0.425)]O3 have been studied. We have observed a relaxation in the amorphous phase of the composite. The structural relaxation studied is irreversible and thermally activated, and dependences of its parameters on temperature and the Ni content are discussed in terms of the model of stress relaxation in local regions of the amorphous material. [ABSTRACT FROM AUTHOR]

The purpose of this work is to study the effect of rapid thermal annealing (RTA) with halogen lamps on the structural and phase characteristics of lead zirconate-titanate (PZT) films. The PZT thin films with a thickness of 1.0 ± 0.1 μm were deposited by high-frequency reactive plasma sputtering in an oxygen atmosphere on oxidized silicon and silicon substrates with orientation (100). After deposition, the PZT films subjected to RTA at temperatures of 500 °C, 600 °C and 700 °C at a rate of 60 °C/s. The structural-phase composition of PZT films was determined with X-ray diffraction analysis. Studies of heterostructures with scanning electron microscopy methods have shown that increase in the temperature of the RTA leads to a qualitative change in the structural-phase state of the PZT film as compared to its initial state. This makes it possible effectively using of RTA in the formation of PZT films with specified parameters. [ABSTRACT FROM AUTHOR]

Effects of cation substitutions on crystal structure parameters, microstructure, dielectric and ferroelectric properties of ceramic solid solutions (Na0.5Bi0.5)(Ti1-xMgx)O3 with x = 0 ÷ 0.1 were studied. Phase transitions near 400 K demonstrate a pronounced relaxor behavior typical for (Na0.5Bi0.5)TiO3 (NBT) based compositions conditioned by presence of polar nanoregions in nonpolar matrix. Changes in the perovskite structure parameters, microstructure, and functional properties of Mg2+ modified NBT ceramics confirmed the influence of the acceptor dopant amount on their properties. Increase in total conductivity at high temperatures and effects of dielectric relaxation were observed with increasing amount of magnesium cations indicating enhancement of ionic conductivity. [ABSTRACT FROM AUTHOR]

In this paper, Li4Ti5O12 was prepared by high temperature solid-state method using titanium dioxide as titanium source and lithium carbonate as lithium source. The effects of lithium-titanium molar ratio, calcination temperature and sucrose as carbon source on the preparation of Li4Ti5O12 were studied. The experimental results show that when the molar ratio of lithium to titanium is 0.95 and the calcination temperature is 800 °C, pure phase Li4Ti5O12 can be prepared. The addition of sucrose carbon source effectively reduces the agglomeration of the product, making the particle size of the prepared lithium titanate sample about 1–2 microns. The first full specific capacity of pure lithium titanate is 160 mAh.g-1 at 0.1 C ratio and 123 mAh/g at 1 C ratio. After adding sucrose, the first charge-discharge specific capacity of lithium titanate was 168 mAh/g at 0.1 C ratio, 150 mAh/g at 1 C ratio, and the high specific capacity of lithium titanate with changed properties increased significantly after adding sucrose. [ABSTRACT FROM AUTHOR]

Effects of cation substitutions on crystal structure parameters, microstructure, dielectric and ferroelectric properties of ceramic solid solutions (Na0.5Bi0.5)(Ti1-xMgx)O3 with x = 0 ÷ 0.1 were studied. Phase transitions near 400 K demonstrate a pronounced relaxor behavior typical for (Na0.5Bi0.5)TiO3 (NBT) based compositions conditioned by presence of polar nanoregions in nonpolar matrix. Changes in the perovskite structure parameters, microstructure, and functional properties of Mg2+ modified NBT ceramics confirmed the influence of the acceptor dopant amount on their properties. Increase in total conductivity at high temperatures and effects of dielectric relaxation were observed with increasing amount of magnesium cations indicating enhancement of ionic conductivity. [ABSTRACT FROM AUTHOR]