Nano BaTiO3 Research Articles

Preparation and properties of BaTiO3 filled butyl rubber composites for flexible electronic circuit applications

Butyl rubber–micron barium titanate (BR/BT) and butyl rubber–nano barium titanate (BR/nBT) composites were prepared by sigma mixing followed by hot pressing. The tensile tests show that both the composites were mechanically flexible. The microwave dielectric properties of both BR/BT and BR/nBT composites were investigated as a function of ceramic loading and were found to be improved with filler content. The butyl rubber has a relative permittivity (er) of 2.4 and loss tangent (tan δ) of 0.0017 at 5 GHz. At a filler loading of 0.24 volume fraction (vf) of micron sized barium titanate (BaTiO3) powder loading, the composite attained a er of 7 and tan δ of 0.014 and for the same filler content of nano BaTiO3 the composite have er of 8.9 and tan δ of 0.019 at 5 GHz. The thermal and mechanical properties of both the composites were investigated. The experimental values of er of both BR/BT and BR/nBT composites for different volume fractions were compared with theoretical models.

Effect of addition of BaTiO3 nano particles on the electrical transport properties of YBCO superconductor

The flux pinning properties of YBCO bulk superconductors synthesized by conventional solid state route and are added with different weight% (x=0, 0.5, 1, 2, 3, 5) of nano BaTiO3 which are prepared by a modified combustion route are studied systematically. The phase analysis of the samples was done by using X-ray diffraction and scanning electron microscopy. Temperature-resistivity measurements, magnetic field dependence of critical current density (Jc-B Characteristics) and flux pinning force calculations were done at 77 K. From the SEM images the microstructure of the sample showed a relative uniform distribution of the nano-particles within the specimen. We found that, even though the transition temperature (Tc) does not change considerably with the BaTiO3 addition, both the critical current density (Jc) and flux pinning force (Fp) increased systematically up to 2 wt% BaTiO3 in the composite, in the presence of magnetic field ranging between 0 and 0.6 T. The Jc value in 2 wt% BaTiO3 added sample showed at least 250% larger than that of the pure YBCO. Also the flux pinning force calculated for the 2 wt% BaTiO3 added is found to be enhanced more than 9 times that of pure YBCO. These observations suggest that the BaTiO3 addition to the Y-123- compounds improve the electrical connection between superconducting grains to result in the increase in Jc.

Electromagnetic properties and microwave-absorption properties of BaTiO3/BaZn2Fe16O27 composite in 2–18 GHz

BaTiO3/BaZn2Fe16O27 composites were prepared by traditional solid state method, BaTiO3 nano particles were coated around with the BaZn2Fe16O27 ferrite with hexagonal plate structure. The prepared composite particles were characterized with X-ray diffraction, scanning electron microscopy, and vector network analyzer. With the increase of BaTiO3 content, the complex permittivity of the composites increases, while the complex permeability decreases; The sharp peaks of the magnetic loss appear at 8.72 and 14.0 GHz, and the peak values are 1.64 and 0.69, respectively, when the mole ratio of BaZn2Fe16O27/BaTiO3 is 10:5; The matching thickness of BaTiO3/BaZn2Fe16O27 composites is 2.5 mm when the mole ratio of BaZn2Fe16O27/BaTiO3 is 10:5, and the minimum reflection loss reaches −33.49 dB at 8.56 GHz; There are more than one loss peak appeared in the reflection loss cures, and the effective absorption frequency (RL < −10 dB) ranges from 7.92 to 14.96 GHz with a thickness of 3 mm.

Graphite nanoplatelets and/or barium titanate/polymer nanocomposites: fabrication, thermomechanical properties, dielectric response and energy storage

Epoxy composites reinforced with (1) micro-size barium titanate (BaTiO3), (2) nano-size BaTiO3, (3) graphite nanoplatelets (GNP), (4) combination of micro and nano BaTiO3 and (5) combination of BaTiO3 and GNP were fabricated and studied, in terms of the type, size and amount of the filler content. Scanning electron microscopy and X-ray diffraction spectra were employed for the investigation of the systems’ morphology. Dynamic mechanical analysis, static mechanical tests and broadband dielectric spectroscopy were used in order to study the properties of the produced systems. Reinforced systems exhibit higher values of storage modulus and dielectric permittivity compared to neat epoxy. Dielectric spectra reveal the presence of two relaxation processes arising from the glass to rubber transition of the polymer matrix (α-mode), and the re-orientation of polar side groups of the polymer chains (β-mode). Finally, the energy storage efficiency of the prepared composite systems was examined in terms of the energy...

Structural and DC conduction studies on vacuum evaporated BaTiO3 thin films prepared from BaTiO3 nano particles synthesised by wet chemical method

BaTiO3 nanoparticles prepared by wet chemical method were thermally grown onto well cleaned glass substrates under the vacuum of 2×10−5Torr, using 12A4 Hind Hivac coating unit. An Al–BaTiO3–Al sandwich structure has been used for electrical conduction properties in the temperature range 303–423K. The composition of nanoparticles and thin films were identified by EDS spectrum. The structural studies have been performed by the X-ray diffraction (XRD) technique. The X-ray analysis showed that the nano particle has a tetragonal structure and deposited films at a lower thickness amorphous in nature, whereas the crystallinity increases with increase of thickness. In the DC conduction studies, the current–voltage characteristics of the films showed ohmic conduction in the low voltage region. In the higher voltage region, a space charge limited conduction (SCLC) takes place due to the presence of the trapping level. The activation energy was estimated and the values found to decrease with increasing applied voltage. The zero field value of the activation energy is found to be 0.31eV. The free carrier mobility, carrier density and trap density values were calculated and reported in this paper.

Characterization, dielectric and electrical behaviour of BaTiO3 nanoparticles prepared via titanium(IV) triethanolaminato isopropoxide and hydrated barium hydroxide

A new sol-precipitation technique for the preparation of nano BaTiO3 crystallite has been developed by reacting 0·2 M each of Ti(IV) triethanolaminato isopropoxide and hydrated barium hydroxide in methanol such that the molar ratio of Ba : Ti is 1·02 at 80 °C under stirring (1200 rpm) for one hour in alkaline media using tetra methyl ammonium hydroxide (TMAH). It was calcined at 100 °C for 12 h. Structural and compositional properties were investigated by XRD, SEM, EDX, TEM, SAED and DLS techniques. FT–IR and TG–DTA were used to characterize its purity and the thermal stability. The BaTiO3 particles prepared were found to be spherical, homogeneous and cubic in structure. The particle size was found to be 23–31 nm. The dielectric constant and dissipation factor after sintering at 400 °C were 5379 and 0·63, respectively at 100 Hz frequency. The a.c. conductivity (σ a.c.) was found to be 2 × 10–5 S-cm–1 at room temperature (30 °C). It increased with increasing temperature up to 50 °C and decreased with further increase in temperature. The impedance was 3·37 × 105 ohms at room temperature. It decreased with increasing frequency.

Synthesis Mechanism of Nano BaTiO3 Particles at Low Temperature by Molten Salt Method

Synthesis Mechanism of Nano BaTiO3 Particles at Low Temperature by Molten Salt Method

Effect of silver incorporation into PVDF-barium titanate composites for EMI shielding applications

Composites of polyvinylidene fluoride (PVDF) with micron and nano sized BaTiO3 powders were developed for electromagnetic interference (EMI) shielding applications in the X band. PVDF-nano BaTiO3 composites show better shielding property compared to PVDF-micron sized BaTiO3 composites. The composite of PVDF with 40vol% of nano BaTiO3 showed the best EMI shielding effectiveness and is about 9dB. The contributions from reflection and absorption to the total EMI shielding effectiveness is same for the PVDF-BaTiO3 composites. Addition of small amount of silver particles improved the shielding properties of these composites due to the increased conductivity. An EMI shielding effectiveness of about 26dB is obtained in the measured frequency range for the PVDF-20vol% nano BaTiO3-10vol% Ag composite of thickness 1.2mm. Novel three phase composite combining the advantages of metal, nano ceramic and polymer is obtained with the potential for effective EMI shielding applications.

Effect of Water in the Synthesis of Nano BaTiO3 Particle Using Potassium Hydroxide

Effect of Water in the Synthesis of Nano BaTiO3 Particle Using Potassium Hydroxide

Phase coexistence evolution of nano BaTiO3 as function of particle sizes and temperatures

Using high resolution synchrotron x-ray diffraction, we systemically study the crystal structure evolution of nano BaTiO3 as function of temperatures and particle sizes. In the temperature range from 200 K to 450 K, the nano BaTiO3 with different particles in the range from 5 nm to 100 nm are phase coexisting. The phase fraction evolutions of different nano BaTiO3 indicated that there is an anomaly at particle size around 20 nm, a phase reentrance taking place. The competition of the shear stresses and the compressive stresses on the particle surface, and the delicate balance between them are responsible for the reentrance phenomenon.

Microwave Dielectric Characteristics of Butyl Rubber- Barium Titanate Composites

Butyl rubber-micron barium titanate (BR/BT) and butyl rubber-nano barium titanate (BR/nBT) composites were prepared by sigma mixing followed by hot pressing. The tensile tests show that both the composites were mechanically flexible. The microwave dielectric properties of both BR/BT and BR/nBT composites were investigated as a function of ceramic loading and were found to be improved with filler content. The butyl rubber has relative permittivity (εr) of 2.4 and loss tangent (tan δ) of 0.0017 at 5 GHz. At a filler loading of 0.24 volume fraction (vf) of micron sized barium titanate (BaTiO3) powder loading, the composite attained a εr of 7 and tan δ of 0.014 and for the same filler content of nano BaTiO3 the composite have εr of 8.9 and tan δ of 0.019 at 5 GHz. The thermal stability of the relative permittivity of both the composites was investigated. The experimental values of εr of both BR/BT and BR/nBT composites were compared with theoretical models.

Uniform Coating of Nanometer‐Scale BaTiO3 Layer on Spherical Ni Particles via Hydrothermal Conversion of Ti‐Hydroxide

A uniform BaTiO3 nano layer was coated on spherical Ni particles for multilayer ceramic capacitor applications via a Ti‐hydroxide coating using the controlled hydrolysis of a TiCl4 butanol solution containing (C2H5)2NH (diethylamine, DEA) and its subsequent hydrothermal reaction at various [Ba(OH)2], residual [DEA], and hydrothermal temperatures. The hydrothermal conversion was successful at [Ba(OH)2]≥0.065M (Ba/Ti≥1.3) and T≥150°C, and the residual DEA in the Ti‐hydroxide coating layer not only affected the formation of the BaTiO3 phase but also resulted in a rough surface morphology. When a minimal amount of DEA was involved in the formation of Ti‐hydroxide, a uniform BaTiO3 coating with a clean surface morphology could be attained, which was confirmed by elemental mapping of the coated powder and the observation of hollow spheres after removing the Ni core. The BaTiO3 coating was very effective not only in preventing Ni oxidation but also in shifting the starting point of Ni densification to a higher temperature.

Fabrication and structure studies of Co：BaTiO3 nano composite thin films

Co:BaTiO3 nano_composite thin films on single_crystal magnesia(100) were successfully fabricated by pulsed laser deposition. The morphology and microstructure of the thin films were investigated via atomic force microscope, x_ray diffractometer and Raman spectroscopy. The results show that the thin films consisted o f a highly c_axis oriented tetragonal phase. The surfaces of the thin films were uniform, compact and of atomic smoothness (RMS=015nm). The co particles, of monodisperse distribution, were found to be well dispersed in the matrix Co: BaTiO3. With increasing Co grain size, the intensities of Raman peaks were wea kened and their width broadened.

Structural study of nano BaTiO3 powder by Rietveld refinement

The barium titanate (BaTiO3) powder with the average particle size of 100 nm was synthesized by the hydrothermal processing using TiCl4 and Ba(OH)2 as precursors. The Rietveld refinement, the magic angle spinning nuclear magnetic resonance (MAS NMR) and the Raman spectroscopy were employed to get the structural information of the nano BaTiO3 powder. The structural parameters for the nano BaTiO3 powder were successfully determined by the Rietveld refinement based on the analysis of MAS NMR and Raman spectra. The final weighted R-factor, Rwp, was 6.89% and the goodness-of-fit indicator, S (= Rwp/Re), was 1.30. The mass fraction of cubic and tetragonal phases based on the refined scale factors for the two phases was 82.0 and 18.0%, respectively. The lattice parameters of cubic and tetragonal phases were a (= b=c) = 4.0185(1) Å, a (= b) = 4.0022(1) Å, and c=4.0318(5) Å, respectively.

Influence of BaTiO3 Nano Particle on Paste and Sintering Properties of Ni Internal Electrode Films by MLCC

Aiming at obtaining a thinner electrode layer, Ni powder of 0.2μm grain size was used and BaTiO3 particles of either 30 nm or 50 nm in size were added. The results indicate that when BaTiO3 nanoparticles with good dispersibility are added to Ni powder of 0.2μm, it is possible to suppress sintering of the Ni electrode paste film by adding BaTiO3 particles of 30 nm size, compared to the film using paste without any addition or with 50 nm BaTiO3 particles. This was clarified from the results of the firing shrinkage rate and the fine structure of the sintered surface.

Study of microstructural behavior and nonadiabatic small polaron hopping conduction in BaTiO3 doped lead-vanadate glass and glass-ceramics dispersed with ferroelectric nanocrystals

Multicomponent semiconducting oxide glasses like (80 V2O5–20 PbO)+xBaTiO3 (x=5–30 wt %) dispersed with nanocrystalline BaTiO3 have been prepared by a fast quenching technique. Results of microstructural study and transport properties (between 80 and 450 K) of these glasses and some glass ceramics have been reported in this article. It has been shown from x-ray diffraction, scanning electron microscopic, and other studies that homogeneous glasses are formed with wide concentrations of BaTiO3 (x⩽30 wt %). Transmission electron microscopic study, however, indicates the presence of nanocrystalline phases in the glass matrix. Mott’s variable range (nonadiabatic) hopping conduction mechanism is found to be valid at the low temperature regime (below θD/4, θD being the Debye temperature) while in the high temperature regime (above θD/2), the polaron hopping models of Schnakenberg as well as Emin and co-workers can quantitatively predict the conductivity data for all these special types of multicomponent glass-nanocrystal composites. The model parameters, obtained from best fit of the experimental data with these models, are consistent with the glass compositions. The dielectric constants of these glasses are found to be very high (comparable to that of bulk BaTiO3) and about two orders of magnitude higher than those of BaTiO3 free (80 V2O5–20 PbO) and other transition metal oxide glasses. This novel character is considered to be due to the embedded nanocrystalline BaTiO3 phases. The glass samples annealed at 300 °C for 9 h in air also showed nano and microcrystalline BaTiO3 phase along with traces of PbV2O6, PbTiO3, TiO2, and Pb2V2O7 phases. Broad anomaly (with a maximum around 390 K) is observed from the thermal variation of dielectric constant data of these partially annealed glass-ceramic samples. This anomaly resembles to the anomaly observed around the Curie temperature (∼393 K) in bulk ferroelectric BaTiO3 crystal.