Addition Of BaTiO3 Research Articles

Improvement in Electrical Properties of (Bi0.5Na0.5)TiO3 (BNT) Ceramics Using the Seed-Induced Method

(Bi0.5Na0.5)TiO3 (BNT) lead-free ceramics were prepared by the seed-induced technique using different particle sizes of BaTiO3 (BT) powder as seeds. The BT seeds was synthesized by the molten-salt method and then calcined at different temperatures of 750 (750BTs), 800 (800BTs) and 850 °C (850BTs). The pure perovskite seeds (5 mol%) were mixed with the starting materials of the BNT system for conventional mixed oxide method. After that, the mixture was calcined and sintered at 900 °C for 2 h and 1100 °C for 2 h, respectively. From results it was found that the particle size of BT seed increased with calcine temperature increase from 750 to 850 C. The samples of non-BT seed (S0) and BT seed-added (S1, S2 and S3) showed pure perovskite phase. Average density values were in the range of 5.53-5.77 g/cm3. Dielectric constant (εr) measured at room temperature (at 1 kHz) was in the range of 732.04-788.59. The dielectric loss (tanδ), remnant polarization (Pr) and coercive field (Ec) values decreased with the addition of BT seed. The highest piezoelectric coefficient (d33) ∼156 pC/N was obtained for the sample of 850BTs (S3).

Stretching-induced phase transitions in barium titanate-poly(vinylidene fluoride) flexible composite piezoelectric films

Improving the piezoelectric performance of poly(vinylidene fluoride) (PVDF) is important for many applications, including energy harvesting. The addition of barium titanate (BaTiO3) nanoparticles in the polymer matrix is a popular method to facilitate β phase formation in PVDF films. For pure PVDF, mechanical drawing (i.e. stretching) has also been shown to increase piezoelectric performance. This work examines, for the first time, the combined effect of stretching and BaTiO3 addition on phase transformations in BaTiO3-PVDF composite films. The results indicate that an alternative phase transformation mechanism occurs during the stretching of PVDF composite films. While stretching of pure PVDF films results in the conversion of non-polar α phase into the electroactive β phase, stretching of BaTiO3-PVDF composite films results primarily in the conversion of weakly electroactive γ phase into the more electroactive β phase. Overall, stretching of BaTiO3-PVDF films is shown to be beneficial for increasing β phase content of PVDF.

Influence of the BaTiO3 addition to K0.5Na0.5NbO3 lead-free ceramics on the vacancy-like defect structure and dielectric properties

A study on the induced changes in the vacancy-like defect structure and the dielectric properties of K0.5Na0.5NbO3 ceramics by the addition of different amounts, between 0% and 7%, of BaTiO3 is presented. The samples were prepared by a mechanochemically activated solid-state reaction method. The structural evolution due to the orthorhombic to the tetragonal phase transition of the KNN doped samples was followed using X-ray diffraction and Raman spectroscopy. The use of positron annihilation lifetime spectroscopy allowed to identify the defect structure at sub-nanometric scale and the nature of the vacancy-like defects generated by the phase transition. The obtained results are discussed considering the lattice symmetry change and the defects structure formed due to the replacement of alkaline and niobium ions by barium and titanium ones. Additionally, changes in the dielectric properties are discussed in terms of the structural modifications of the different KNN-based ceramics involving different kinds of vacancy-like defects.

Mechanical and Dielectric Properties of Hot-pressed Si3N4 Ceramics with BaTiO3 Addition

Mechanical and Dielectric Properties of Hot-pressed Si₃N₄ Ceramics with BaTiO₃ Addition

Structural and Microstructural Properties of Systems Based on Bi0.5Na0.5TiO3

Perovskites based on bismuth sodium titanates, Bi0.5Na0.5TiO3 (BNT), are incorporated into lead-free piezoelectric materials. Although BNT was discovered five decades ago, many aspects such as the structural complexity and the modifications produced when it is combined with other perovskites are not clearly understood. We studied the structural and microstructural properties of BNT upon addition of BaTiO3 (BT) and SrTiO3 (ST) during sol-gel synthesis. We characterized the ceramic powders by infrared and Raman spectroscopy, X-ray diffraction and scanning electronic microscopy. The addition of BT/ST modified the bonds, generating coexistence and phase transition and confirmed the existence of a morphotropic phase boundary.

Synthesis of BaTiO3 nanoparticles by sol-gel assisted solid phase method and its formation mechanism and photocatalytic activity

In this paper, a new sol-gel assisted solid-phase method for the preparation of nano BaTiO3 ceramics is proposed to solve the shortcomings of too high temperature in solid-phase preparation and NO2 pollution produced by sol-gel method. The TiO2 precursor gel is used to encapsulate BaCO3, which can effectively reduce the temperature during calcination. In this study, XRD, FT-IR, XPS, TEM, SEM and TG-DSC were used to explore the structure and evolution of samples at different stages. In addition, the crystallization and growth process of BaTiO3 were further studied. Then the energy band structure and electron hole recombination of different samples were analyzed by UV–Vis and PL spectra. Finally, the photocatalytic activity of different samples was investigated by photolytic water experiment. The results showed that BaTiO3 was initially generated at 600 °C and pure phase BaTiO3 was generated at 800 °C. In the photolytic water experiment, the samples calcined at 700 °C showed the best photocatalytic performance, with a hydrogen production rate of 43.74 μmol/g/h.

Electrical conductivity and dielectric properties of solid polymer nanocomposite films: Effect of BaTiO3 nanofiller

Polymer nanocomposite comprising of PEO-PVC + LiClO4 with BaTiO3 as nanofiller were synthesized by the solution cast technique. The dispersion of the nanofiller in the polymer matrix promotes fast ion migration. Impedance study reveals that the ionic conductivity is enhanced by the addition of BaTiO3 and the maximum value is 2.35 × 10−5 S cm−1 for 3 wt. % BaTiO3 attributed to favorable conductive path formation for cation. The ion transference number is close to unity and the voltage stability window is of the order of 3.5 V. The complex dielectric permittivity, dielectric loss, complex conductivity, was studied and fitted with the corresponding established expression in the entire frequency range (1–100 kHz). The dielectric constant increases with the addition of the nanofiller and is attributed to the complete salt dissociation. The ac conductivity analysis displays a shift of dispersion region toward high frequency which is attributed to the faster ion migration and also evidenced by lowering of relaxation time. It has been noticed that the relevant parameters like ionic conductivity, ion transference number, voltage stability and the dielectric parameters are dependent on the content of nano-sized BaTiO3 filler content. A systematic ion transport mechanism has been proposed to highlight the role of nanofiller in enhancing the desired parameters.

Entropy and fractal nature

Existing, the biunivocal correspondents between the fractal nature and the nature discovered by fractals is the source and meeting point from those two aspects which are similar to the thermodynamically philosophical point of view. Sometimes we can begin from the end. We are substantial part of such fractals space nature. The mathematics fractal structures world have been inspired from nature and Euclidian geometry imagined shapes, and now it is coming back to nature serving it. All our analysis are based on several experimental results. The substance of the question regarding entropy and fractals could be analyzed on different ceramics and materials in general. We have reported the results based on consolidation BaTiO3- ceramics by the standard sintering technology, performed with BaTiO3 and different additives (MnCO3, CeO2, Bi2O3, Fe2O3, CaZrO3, Nb2O5, Er2O3, Yt2O3, Ho2O3). Thermodynamic principles are very important. Beside the energy and temperature, the entropy as a measure between the order and disorder (chaos) is very important parameter. In this paper, we establish the relation between the entropy and fractal that opens new frontiers with the goal to understand and establish the order-disorder relation.

Design of lead-free PVDF/CNT/BaTiO3 piezocomposites for sensing and energy harvesting: the role of polycrystallinity, nanoadditives, and anisotropy

Lead-free piezoelectric composites with polymeric matrices offer a scalable and eco-friendly solution to sensing and energy harvesting applications. Piezoelectric polymers such as PVDF are particularly interesting because of the possibility to engineer the performance of these materials through addition of higher-performance piezoelectric inclusions and nanomaterials and to scalably manufacture such composites by emerging techniques such as 3D printing. This work makes two contributions, namely towards composite design and towards development of accurate effective property models. In the context of composite design, we evaluate the piezoelectric performance of PVDF modified by the addition of polycrystalline-BaTiO3 and multiwalled carbon nanotubes. Firstly, the addition of BaTiO3 dramatically improves the electric field within the composite offering significant advantages specially at low BaTiO3 concentrations. Secondly, the addition of carbon nanotubes to the matrix, particularly at higher BaTiO3 loadings, leads to an order of magnitude increase in the piezoelectric flux generation. Further enhancement in the flux generation is also possible by tuning the polycrystallinity of the BaTiO3 inclusions. However, these behaviours are inclusion-driven and the piezoelectric behaviour of the matrix does not contribute to this improvement. Importantly, a small addition of BaTiO3 and CNT into the PVDF matrix, away from percolation, can simultaneously improve flux and electric field generation. In this part of the work, we assume an isotropic PVDF matrix. Given that PVDF is elastically anisotropic, the second aspect of this work is the development of an effective property model for CNT-modified PVDF, taking into account the elastic anisotropy of poled PVDF, to predict the elastic coefficients of CNT-modified PVDF matrices, thus undertaking a key step towards modelling anisotropic piezoelectric composites. We show that the anisotropy-based model makes similar predictions in the effective composite behaviour, indicating that in the case of PVDF-based piezocomposites, the anisotropy of the matrix does not significantly affect the piezoresponse.

Graphene/barium titanate/polymethyl methacrylate bio-piezoelectric composites for biomedical application

The introduction of BaTiO3 (BT) particles into biomaterials, such as polymethyl methacrylate (PMMA) bone cement, is among the effective ways to improve their osteoinductivity. However, excessive addition leads to mechanical degradation. An important problem to solve is the manner by which piezoelectric properties matching human bones can be obtained under the premise of sufficient mechanical properties. The piezoelectric effect is obtained by adding BT particles into PMMA bone cement. The piezoelectric coefficient close to the human bone is obtained at a relatively low BT addition amount by adding graphene on this basis. High mechanical properties can also be obtained. Graphene increases the piezoelectric coefficient by increasing the conductivity, dielectric constant, and effective polarization voltage of graphene (G)/BT(BaTiO3)/PMMA bio-piezoelectric composites. The compression strength of the aforementioned composites increases from 83.5 MPa to 89.5 MPa after the addition of 0.5 vol% graphene, and the requirements of bone implant materials were met. G/BT/PMMA bio-piezoelectric composites have no cytotoxicity, and graphene can also promote cell adhesion and proliferation on the composite's surface. The polarized bio-piezoelectric composites can improve cell morphology and promote cell proliferation. The number of cells increases with increasing piezoelectric coefficient. The composite has potential application prospects in various fields, such as oral cavity and bone implant.

Enhanced dielectric and multiferroic properties in BaTiO3 doped Bi0.85Nd0.15Fe0.98Mn0.02O3 ceramics

The multiferroic ceramics of (1-x) Bi0.85Nd0.15Fe0.98Mn0.02O3-x BaTiO3 (x = 0, 0.275, 0.3 and 0.325) were prepared by the conventional solid phase reaction. The crystal structure, microstructure, dielectric, ferroelectric and magnetic properties were systematically investigated. The X-ray diffraction pattern indicates that the structure of Bi0.85Nd0.15Fe0.98Mn0.02O3 is rhombohedral and the space group is R3c. Rietveld refinement shows that with the introduction of BaTiO3, the crystal structure of the material transformed from rhombohedral (R3c) to pseudo-cubic (P4mm). Scanning electron microscopy analysis shows that the average grain size decreases with the introduction of BaTiO3. Temperature dependence of the dielectric constant and the dielectric loss indicate that the introduction of BaTiO3 leads to ferroelectric relaxation. The dielectric constant and the dielectric loss are improved in sync. The leakage current density is reduced by about two orders of magnitude under the electric field of 15 kV/cm. The ferroelectricity and ferromagnetism are greatly improved after the addition of BaTiO3 seen from the polarization hysteresis (P-E) loops and the magnetization hysteresis (M-H) loops.

Synergistic enhanced dielectric properties of PVDF nanocomposites containing γ-oxo-pyrenebutyric acid functionalized graphene and BaTiO3 nanofillers

Abstract To investigate the synergies of graphene and BaTiO3 on the morphology and dielectric behavior of poly(vinylidene fluoride) (PVDF), γ-oxo-pyrenebutyric acid-modified graphene (GPA) and BaTiO 3 were incorporated into PVDF matrix by using solution-cast and hot-pressing method. π-π interaction between graphene (Gra) and γ-oxo-pyrenebutyric acid (PA), and the hydrogen bonding effect between hydroxy groups on BaTiO3 and PVDF can improve the dispersity of Gra and BaTiO3 in PVDF matrix. The addition of BaTiO3 improved further the dielectric permittivity that originates from high dielectric BaTiO3 , and remarkable interfacial polarization effect between PVDF and fillers, and the non-conducting organic groups of PA can support the low loss and conductivity in PVDF/GPA/BT composites that shows potential application as high dielectric material over a broad temperature range.

Calculation and Measurement of Elastic Modulus of Nano BaTiO<sub>3</sub> Enhanced IPMC

The Mechanical parameters of elastic modulus about the preparation technology of BaTiO3/IPMC (Ionic Polymer Metal Composite) were studied. In order to get the relationship between the elastic modulus and the different content of BaTiO3/IPMC the Mori-Tanaka method based on Eshelby equivalent inclusion theory was used. In order to verify the correctness of the model, Solution casting method was used to prepare different content of BaTiO3/IPMC (100:1,100:3,100:5,100:7). The elastic modulus of IPMC was texted by tensile testing and the bending test of cantilever. The result shows that: The elastic modulus of IPMC film increased by 6.3% ~ 84.7% with addition of BaTiO3. It was proved that the reinforced fillers could greatly improve the elasticity modulus of IPMC.

Barium titanate‐based nanodielectrics of two chemically recyclable thermosets

AbstractIn this work was investigated the effect of the addition of barium titanate (BaTiO3) on electrical properties of two chemically recyclable thermosets, polyhemiaminal (PHA) and polyhexahydro‐s‐triazine (PHT), both fabricated from 4,4′‐oxydianiline (ODA), an ether derivative of aniline and paraformaldehyde. Thermal and mechanical properties as well as chemical recyclability of the two polymers and their nanocomposites/nanodielectrics were also investigated. In addition, a quantitative analysis was conducted of the nanoparticle dispersion in the PHA‐/PHT‐based BaTiO3‐containing nanocomposites using transmission electron microscopy imaging and the nearest‐neighbor distance index and this index was used to analyze the investigated properties in connection with the proper mechanisms. Regarding the electrical properties for both neat polymers, conductivity values of the order of 10−8 S m−1 at 100 Hz were observed and dielectric constant values close to 2.80 for both polymers at 1 kHz. The addition of 0.5 wt% of BaTiO3 ferroelectric nanoparticles increased by about 44% the dielectric constant (1 kHz) and conductivity (102 Hz) of the PHA‐based nanocomposite. PHA and PHT exhibited glass transition temperature (Tg) values in the range 125–180 °C. An increase of 7 °C in Tg was observed after the incorporation of 0.5 wt% of BaTiO3 into PHA. Concerning the mechanical properties, values in the range 4.00–4.45 GPa for reduced modulus and 0.30–0.43 GPa for nanohardness for PHA and PHT polymers were observed. Independently of filler content or polymer matrix, both mechanical properties were enhanced after the addition of BaTiO3. The chemical recycling of PHA/PHT and all nanocomposites in the initial ODA reagent after sulfuric acid treatment was successfully characterized using the NMR and Fourier transform infrared spectroscopic techniques. © 2018 Society of Chemical Industry

Effect of sintering temperature and piezoelectric coefficient (d<SUB align="right">33) enhancement on rice husk silica ceramics with BaTiO<SUB align="right">3 addition

Piezoelectric coefficient (d33) indicates the potential of a material to have piezoelectric properties. Once the piezoelectric properties of a material have been known, the application of that material will be easily determined. In this paper, study on piezoelectric coefficient for silica ceramic samples derived from rice husk ash (RHA) sintered at 1000°C, 1100°C and 1200°C temperatures has been carried out. BaTiO3 was added to enhance the piezoelectric d33 values in the rice husk. Characterisation of piezoelectric coefficient (d33) of pure rice husk ash, rice husk samples with 5 wt% and 10wt% BaTiO3 addition is discussed. The value of d33 increases with increasing percentage of BaTiO3 addition.

Structural transformations and physical properties of (1 − x) Na0.5Bi0.5TiO3 − x BaTiO3 solid solutions near a morphotropic phase boundary

Piezoelectric and other physical properties are significantly enhanced at (or near) a morphotropic phase boundary (MPB) in ferroelectrics. MPB materials have attracted significant attention owing to both fundamental physics as well as the possibility of well-regulated energy and information storage devices which are dominated by lead (Pb)-based materials. Here, we report the crystal structure, Raman spectra, dielectric constant and polarization near the MPB of lead free (1 − x) Na0.5Bi0.5TiO3 − x BaTiO3 (0.00 ⩽ x ⩽ 0.10) solid-solution, prepared by sol–gel auto combustion technique and sintered by microwave sintering technique. With the addition of BaTiO3 into Na0.5Bi0.5TiO3, it induces a structural phase transition from R3c (a single phase) to R3c + P4mm (a dual phase) close to x = 0.06 and 0.07 and transform to a high symmetry tetragonal phase P4mm at higher compositions (x = 0.08 to 0.10) as evident from our x-ray Rietveld refinement and Raman spectroscopic results. We perform first-principles calculations based on density functional theory that confirm a structural transition from a rhombohedral to a tetragonal phase under increasing x. In the prepared solid solution, an anomalous enhancement of remnant polarization () was observed for x = 0.06 and 0.07, which has been explained based on the existence of the MPB. On the other hand, the value of coercive field was found to be decreased linearly from x = 0.00 to 0.06; it is constant for higher compositions. Further details of the ferroelectric properties on the electric field poled samples have been studied and compared with the as-grown (unpoled) samples.

Ferroelectric β-crystalline phase formation and property enhancement in polydopamine modified BaTiO3/poly (vinylidene fluoride-trifluoroethylene) nanocomposite films

Piezopolymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) films doped with BaTiO3 (BT) and polydopamine coated BT (BT-Pdop) nanoparticles were prepared by spin-coating method. Polydopamine modifies the interfaces of inorganic BT nanoparticles and PVDF-TrFE matrix with its polar hydroxyl groups, enhancing the piezoelectric β-phase. BT-Pdop nanoparticles were obtained in pH 8.5 buffer solution. For ferroelectric PVDF-TrFE, the favorable piezoelectric property comes from its ferroelectricity. Therefore, we studied the ferroelectric property of the nanocomposite films. The nanocomposite thin films possess better ferroelectric property than the pure PVDF-TrFE thin films, as demonstrated by the ferroelectric hysteresis curves. The remanent polarizations are 13.59 and 13.94 μC/cm2 after the doping of 1.0 wt% BT and 1.0 wt% BT-Pdop, respectively, which are about twice that of neat PVDF-TrFE. The piezoelectric β-ferroelectric phase increases with doping, according to X-Ray Diffraction analysis. In addition, the images of polarized optical microscopy and atomic force microscopy also reveal significant enhancement in crystallinity. The neat PVDF-TrFE is a semicrystalline polymer and the size of crystalline spherulites increases with the addition of BT and BT-Pdop nanoparticles. However, even the crystallinity of PVDF-TrFE considerably improved with polydopamine interfacial modification of BT, the increase of remanent polarization due to Pdop is only marginal. We infer that there are other defects at interfaces of BT-Pdop doped PVDF-TrFE nanocomposites which counteract the beneficial effect of the polar OH of polydopamine. Considerable enhancement on ferroelectric property of BT-Pdop doped PVDF-TrFE nanocomposites is expected after these issues are addressed.

Evidence for existence of functional monoclinic phase in sodium niobate based solid solution by powder neutron diffraction

We have carried out systematic temperature-dependent neutron diffraction measurements in conjunction with dielectric spectroscopy from 6 to 300 K for sodium niobate based compounds (1-x) NaNbO3-xBaTiO3 (NNBTx). The dielectric constant is measured as a function of both temperature and frequency. It shows an anomaly at different temperatures in cooling and heating cycles and exhibits a large thermal hysteresis of ∼150 K for the composition x = 0.03. The dielectric constant is found to be dispersive in nature and suggests a relaxor ferroelectric behavior. In order to explore structural changes as a function of temperature, we analyzed the powder neutron diffraction data for the compositions x = 0.03 and 0.05. Drastic changes are observed in the powder profiles near 2θ ∼ 30.6°, 32.1°, and 34.6° in the diffraction pattern below 200 K during cooling and above 190 K in heating cycles, respectively. The disappearance of superlattice reflection and splitting in main perovskite peaks provide a signature for structural phase transition. We observed stabilization of a monoclinic phase (Cc) at low temperature. This monoclinic phase is believed to provide a flexible polarization rotation and considered to be directly linked to the high performance piezoelectricity in materials. The thermal hysteresis for composition x = 0.03 is larger than that for x = 0.05. This suggests that the addition of BaTiO3 to NaNbO3 suppresses the thermal hysteresis. It is also observed that the structural phase transition temperature decreases upon increasing the dopant concentration.

Properties of (1-x)NaCu3Ti3NbO12-(x)BaTiO3 ceramics with various sintering temperatures prepared by conventional solid-state reaction method

ABSTRACTIn the research, the properties of sodium copper titanate niobate – barium titanate [(1-x)NaCu3Ti3NbO12-(x)BaTiO3: (1-x)NCTNO-(x)BT] ceramics prepared by conventional solid-state reaction method with various molecular weight of BT or x between 0.1, 0.3 and 0.5 were investigated. These ceramics were sintered at 975, 1000, 1025 and 1050 oC for 10 h in ambient atmosphere. The phase structure, microstructure, density, micro-hardness and dielectric properties were examined by x-ray diffraction technique (XRD), scanning electron microscopy (SEM), Archimedes method, Vickers micro-hardness tester and impedance analyzer, respectively. It was found that, the addition of BaTiO3 resulted in the formation of second phase which increased upon increasing the BaTiO3 content. Compared to the base composition, the grain sizes of all the (1-x)NCTNO-(x)BT were significantly reduced. The densities of (1-x)NCTNO-(x)BT ceramics and dielectric properties were improved with the addition of BaTiO3. For the effect of sintering temperatures, no substantial change in the crystal structure and grain growth was found whereas an increase in densities and hardness with increasing temperatures were observed. The (0.7)NCTNO-(0.3)BT ceramics sintered at 1025 oC showed the highest density and dielectric constant (∼80500) at room temperature with 1 kHz measurement.

The effect of BaTiO3 addition on the dielectric constant of Si3N4 ceramics

AbstractSi3N4 ceramics with different BaTiO3 contents have been fabricated by pressureless sintering in a N2 atmosphere at 1680°C for 2 h. Al2O3 and Nd2O3 were used as sintering additives to promote the densification of Si3N4 ceramics. The effect of BaTiO3 addition on the densification, mechanical properties, phase compositions, microstructure, and dielectric properties of Si3N4 ceramics was investigated. The relative density and flexural strength of Si3N4 ceramics increased with the addition of BaTiO3 up to 15 wt% and then decreased, while the dielectric constant increased continuously as the BaTiO3 contents increased. The dielectric constant of Si3N4 ceramics can be tailored in the range from 8.42 to 12.96 by the addition of 5 wt%‐20 wt% BaTiO3. Meanwhile, these Si3N4 ceramics all had flexural strength higher than 500 MPa.