BaTiO3 Powders Research Articles

Long-term leaching kinetics and solution chemistry of aqueous BaTiO3 powder suspensions: a numerical model supported experiment.

The advent of lead-free perovskite materials with favorable toxicity profiles has made them candidates for in vivo and environmental applications. However, their tendency to leach A-site cations raises concerns about toxicity, catalytic efficiency, and slurry properties. The present study investigates the long-term leaching kinetics of BaTiO3 powders over 31 days in aqueous solutions of varying pH levels. Using ICP-MS analysis and a numerical model based on the Unreacted Shrinking Core (USC) principle. The study extends the understanding of BaTiO3 stability beyond previously reported timeframes. The findings highlight the material's long-term stability, with implications for biomedical and environmental applications.

Evidence of multiferroic behavior in sintered BaTiO3 obtained from high-energy ball-milled powders

Multiferroic BaTiO3 exhibiting ferroelectric and ferromagnetic behavior was synthesized via the high-energy ball milling of pure BaTiO3 (BTO) powders for durations ranging from 15 to 60 min, followed by pressing and sintering at 1200°C X-ray diffraction patterns of all synthesized samples predominantly revealed a BTO phase with a tetragonal structure and a secondary Ba12Fe28Ti15O84 (BFTO) phase. The BFTO phase was formed after milling for more than 30 min because of chemical interactions between the BTO powder and milling media. Vibrating sample magnetometry confirmed the ferromagnetic nature of the sintered pellets. The specific magnetization increased with increasing milling duration, reaching a maximum value of 1.15 emu/g after 60 min of milling. This increase can be attributed to the distortion of the crystal structure and presence of a secondary phase, as confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Additionally, electrical characterization revealed the dielectric nature of the materials, with relative permittivity ranging from 500 to 1800, maximum spontaneous polarization from 9.77 to 11.31 μC/cm2, coercive field from 3.86 to 11.12 kV/cm, and AC conductivity from 1 x 10−6 to 1 x 10−3 S/cm. The method described in this study is a simple and cost-effective approach to produce multiferroic materials with ferroelectric and relaxor ferroelectric behavior at room temperature, broadening their potential for technological applications.

Room temperature synthesis of BaTiO3 nanoparticles using titanium bis(ammonium lactato) dihydroxide

BaTiO3, known for its exceptional ferroelectric properties, is extensively applied in multi-layer ceramics capacitors (MLCCs). Achieving reliable, high-performance MLCCs requires sophisticated ceramics processes, notably in synthesizing submicron-order BaTiO3 powder with a narrow size distribution. Among various synthesis methods explored for submicron-size BaTiO3 powder, room temperature liquid-phase synthesis is most desirable due to its cost-effectiveness and large batch availability. In this study, we propose a synthesis method for obtaining BaTiO3 nanopowder at room temperature using titanium bis(ammonium lactato) dihydroxide and Ba(OH)2·8H2O as starting materials, reacted in tert-butylamine with NaOH and ethanol. The resulting powder, exhibiting a cubic phase of BaTiO3 with an average particle size of 35.8 nm, was obtained after a 7-day reaction at room temperature. Characterization involved X-ray diffraction, differential thermal analysis‒thermogravimetry, and scanning electron microscopy. Subsequently, the powder was used to sinter a BaTiO3 ceramic, whose dielectric performance was then evaluated.

Dielectric properties and microstructure of BaTiO3-PTFE composites via cold sintering process

The cold sintering process is capable of densifying ceramics and metal powders with other phases into composite materials without inducing chemical reactions between the constituent phases or causing the decomposition of any phases. In this study, we considered the co-sintering of BaTiO3 powders with polytetrafluoroethylene (PTFE) in the grain boundaries. We examined the microstructure and dielectric properties of these composites with different volume fractions of PTFE. The composites were highly dispersive from microstructure and general mixing laws, due to using fine PTFE. Transmission electron microscopy studies demonstrated that the thickness of the PTFE in the grain boundaries was determined with different volume fractions of PTFE. The cold-sintered BaTiO3 composites had high volume resistivity (>1011 Ω·cm), enhancing the resistivity of the cold-sintered pure BaTiO3 using Ba(OH)2·8H2O transient phase. Reliability tests, such as breakdown strength, and Jt curves, were conducted, and the reliability was improved by using fine powders of PTFE with controlled mixing.

Vacancy engineering for high tetragonal BaTiO3 synthesized by solid-state approaches

Conventionally, tetragonality in BaTiO3 powder is attributed to grain size, disregarding the role of Ba/Ti ratio. However, our study reveals a significant impact of Ba/Ti ratio on tetragonality in BaTiO3. With an increase in Ba/Ti ratio from 0.990 to 1.010, particle size remains around 200 nm. Tetragonality initially rises from 1.006 to a maximum of 1.0092 at Ba/Ti = 1.000, then decreases to 1.005. Lower tetragonality is associated with Ba or Ti vacancies, using density functional theory (DFT), we analyzed the electron density and lattice distinction in BaTiO3 powders. Both Ba and Ti vacancies affect lattice distortion, the Ti vacancies leading to more significant lattice expansion and lower tetragonality than Ba vacancies. Using this powder, we fabricated high-density BaTiO3 ceramics and multi-layer ceramics capacitors (MLCCs) with X7R temperature stability (−55 to 125 °C, ±15% coefficient) and excellent reliability. This strategy has broad implications for tetragonal BaTiO3 nanopowders and MLCCs development.

Enhanced performance of hybrid piezo/triboelectric using BaTiO3/polymer composite film modified with rGO

ABSTRACT Hybrid piezo/triboelectric technology is an emerging energy source that can continuously power small electronic devices by harvesting ambient mechanical energy and converting it into electricity. In this work, a high-performance hybrid piezo/triboelectric device was presented. The composite film was synthesized that co-doped BaTiO3 powders (BT) and reduced graphene oxide (rGO) embedded within a host material made of polydimethylsiloxane (PDMS). The hybrid device is made by mixing BT powders into the PDMS to form a series of composite films, ranging from 10% to 45% by wt.%. Additionally, 1–5 wt.% of rGO was loaded into fabricates 40BT/PDMS. The results show that the addition of rGO can improve the uniform dispersion of BT powder in the PDMS matrix. The 4 wt.% of rGO for 40BT/PDMS exhibited the optimal energy harvesting performance among all compositions, achieving notable output voltage and current. This work demonstrates a facile, low-cost approach for obtaining high-performance hybrid piezo/triboelectric by utilizing a composite film BaTiO3 and polymer (PDMS) modified with rGO.

Role of Nd doping on the structural, morphological and optical properties of BaTiO3 nanoparticles hydrothermally synthesized

Herein, we have reported the facile synthesis of pure and neodymium (Nd)-doped BaTiO3 powders via the hydrothermal method. The effects of Nd concentration (2–10 wt %) on the properties of the BaTiO3 powders were studied. Structural and morphological characteristics were realized using X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive X-ray (EDS), and X-ray photoelectron spectroscopy (XPS). Fourier transform infrared (FT-IR), UV–visible, and photoluminescence (PL) spectroscopies were used for optical analyses. XRD results show that all powders crystallized under a cubic structure with an average crystallite size that was in the range of 35–47 nm. SEM micrographs revealed that the grains were spherical-shaped, with an average size found in the range of 232–390 nm. The EDS analysis detected the presence of Ba, Ti, O, and Nd elements in the elaborate materials. XPS data confirms the introduction of Nd3+ in the BaTiO3 and the amphoteric substitution of Nd3+ in the Ba and Ti sites at 6 and 10 wt%. FT-IR spectra indicate the presence of the Ti–O vibration bonds. UV–visible optical spectra illustrate the enhancement of absorbance with Nd doping. PL spectra exhibit ultraviolet, blue, green, and orange emissions in the samples.

Sensitive Luminescence Thermometry through Excitation Intensity Ratio in Eu-Doped BaTiO3.

Optical ratiometric thermometry techniques have gained much attention in recent years due to their reliable and noncontact temperature sensing capability for industrial and biorelated applications. Herein, we exploited the temperature dependence of the absorption band of BaTiO3 (BTO) for novel excitation intensity ratio (EIR) thermometry. Photoluminescence and excitation properties of Eu3+-doped BTO powders were studied as a function of Eu3+ doping concentration. The excitation peak intensities at 397 and 468 nm, corresponding to the 7F0 → 5L6 and 5D2 transitions of Eu3+, were used as EIR parameters. The temperature dependence of the EIR can be explained by the competitive absorption between Eu3+ and the BTO host. The EIR properties were studied in relation to the doping concentration, registering a maximum relative sensitivity (Sr) of 4.89% K-1 in BTO:Eu3+ (0.5%) at 303 K. An amphoteric Eu3+ occupation mode at both Ba2+ and Ti4+ sites was found to interpret the doping concentration dependence of the Sr. The reduced Ba2+ site occupation ratio proved to be responsible for the low Sr values at high Eu3+ doping concentrations. Accordingly, an Eu3+/Ti3+ codoping method was further proposed to improve the Sr by increasing the Ba2+ site occupation ratio. Our result showed that BTO:Eu3+ (0.5%) demonstrated an enhancement of Sr from 4.89 to 6.42% K-1 at 303 K after 2% Ti3+ codoping.

3D Printing of Flexible BaTiO3/Polydimethylsiloxane Piezocomposite with Aligned Particles for Enhanced Energy Harvesting.

With the rapid development of human-machine interactions and artificial intelligence, the demand for wearable electronic devices is increasing uncontrollably all over the world; however, an unsustainable power supply for such sensors continues to restrict their applications. In the present work, piezoelectric barium titanate (BaTiO3) ceramic powder with excellent properties was prepared from milled precursors through a solid-state reaction. To fabricate a flexible device, the as-prepared BaTiO3 powder was mixed with polydimethylsiloxane (PDMS) polymer. The BaTiO3/PDMS ink with excellent rheological properties was extruded smoothly by direct ink writing technology (DIW). BaTiO3 particles were aligned due to the shear stress effect during the printing process. Subsequently, the as-printed composite was assembled into a sandwich-type device for effective energy harvesting. It was observed that the maximum output voltage and current of this device reached 68 V and 720 nA, respectively, for a BaTiO3 content of 6 vol %. Therefore, the material extrusion-based three-dimensional (3D) printing technique can be used to prepare flexible piezoelectric composites for efficient energy harvesting.

Fabrication and properties evaluation of chitosan/BaTiO3 composite membranes for the periodontitis treatment

Periodontitis gradually damages the hard and soft tissues surrounding the tooth, leading to tooth loss. In recent years, the use of biomaterials in periodontitis treatment has expanded, including gels, nanoparticles, microparticles, fibers, and membranes. Among these, membranes have more clinical applications. Due to the ability of the piezoelectric material to regenerate damaged tissues, the aim of this study was to create piezoelectric composite membranes. To achieve this, Barium titanate powder (BaTiO3 powder)—a piezoelectric substance—was synthesized using the hydrothermal method and analyzed with X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). Four types of membranes were fabricated using solvent casting method: three composite membranes with chitosan matrix and BaTiO3 fillers (at 3%, 6%, and 9% weight), and one chitosan membrane without BaTiO3. The microstructure of the membrane surfaces, agglomeration of BaTiO3 in membranes, and hydrophilicity, antibacterial, and electrical properties of the membrane were also investigated. The results indicated that membranes containing 3 and 6% BaTiO3 had suitable surface structure for the periodontitis treatment. Agglomeration of BaTiO3 particles was higher in the membrane containing 9% BaTiO3. The large amount of BaTiO3 improved the antibacterial properties of the membranes. Additionally, the membranes containing BaTiO3 had high electrical properties, especially those with 3% and 6% BaTiO3. Therefore, composite membranes containing BaTiO3, especially membranes containing 6% BaTiO3, are more favorable options than those without BaTiO3 for periodontitis treatment.

Colossal permittivity and excellent temperature stability of BaTiO3 based fine ceramics with controlled grain growth

Dielectric materials with colossal permittivity (CP, εr > 104) have attracted the increasing interest of researchers due to their enormous potential in the fields of sensor, capacitor, energy storage, etc. However, for the explored CP materials, their grains are too large to apply. To control grain growth, the sintering aids of MgO–Al2O3–SiO2 (MAS) cordierite glass and common suppression grain growth of MgO have been introduced to BaTiO3-0.004Y2O3-0.006MnO2 ceramics derived from the commercial BaTiO3 powder with the average grain size of 300 nm. After controlling grain growth, the fine grains with the average grain size of dg ∼300 nm and CP are achieved in BaTiO3 based ceramics sintered in reducing atmosphere. Notably, excellent temperature stability with Δεr/εr25°C lower than 17 % is gained for the present BaTiO3 based ceramics in the temperature range of −60 to 155 °C, meeting the X8S specification (ΔC/C25°C ≤±22 %, −55 °C–150 °C). Based on the X-ray photoelectron spectroscopy (XPS) and Raman spectra, the outstanding dielectric properties of the present BaTiO3 based ceramics is ascribed to the electron-pinned defect-dipole (EPDD) effect induced by YTi′−YBa∙, TiTi′−Vo∙∙−TiTi′ and YTi′−Vo∙∙−TiTi′ defect dipoles. The present BaTiO3 based fine ceramics with colossal permittivity (∼2.9 × 104), low loss (∼0.03) at 1 kHz and room temperature, excellent temperature stability and high resistivity of 3.54 × 109 Ω cm is a promising candidate for the multilayer ceramics capacitor (MLCC).

3D Printing of Hydrogel/BaTiO3 Composite Scaffolds with Highly Improved Mechanical, Electrical, and Degradable Properties

In clinical practice, the restoration of cartilage injury is a tough task. And manufacturing degradable cartilage scaffolds with strong mechanical properties and electrical activity remains a significant issue. In this study, the hydrogel/BaTiO3 composite scaffolds with greatly improved mechanical, electrical, and degradable properties were formed by digital light processing 3D printing. We found that the addition of BaTiO3 powders enabled the significant improvement of the compressive strength (212.8 kPa) and energy absorption (32.0 mJ/m3), which were as three and six times as those of pure hydrogel scaffolds, respectively. Besides, the composite scaffolds showed a voltage output of above 100 mV, which was two orders of magnitude higher than that of pure hydrogel scaffolds. This voltage output allows for the simulation of electrical microenvironment in native tissues that promote cartilage regeneration and remodeling. Finally, the degradation rate of the composite scaffolds reached 7.1% after 14 days of simulated body fluid (SBF) immersion, while that of the pure hydrogel scaffolds was only 2.8%. This study provides insight into the fabrication of high-performance functional scaffolds for treating cartilage defect.

Impact of the change in charge compensation mechanism on the electrical, dielectric, and structural properties of La-doped BaTiO3 ceramics

La-doped BaTiO3 ceramics are essential materials in electronic devices, finding applications in multilayer ceramic capacitors and positive temperature coefficient thermistors. While the electrical properties of La-doped BaTiO3 have been investigated, the impact of its room-temperature resistivity anomaly on dielectric properties remains unclear. We synthesized pristine and La-doped BaTiO3 (0.1 – 0.5 mol%) powders via hydrothermal methods, and then sintered bulk samples. Their resistivities (DC and AC), Curie temperature, room-temperature dielectric constant, and lattice volume with varying La doping concentrations were characterized. Beyond 0.3 mol%, the shift from electronic to ionic charge compensation mechanisms resulted in abrupt changes in resistivities, Curie temperature, and dielectric constant near 0.3 mol%. Given minimal changes in average grain size and relative density near 0.3 mol% La, the dominant factor influencing the dielectric constant peaking near this concentration was the shift in charge compensation mechanism.

Structures, dielectric properties and AC impedance characteristics of BiFeO3–BaTiO3 high-temperature lead-free piezoceramics synthesized by the hydrothermal method

Among the lead-free piezoceramics, ([Formula: see text])BiFeO[Formula: see text]BaTiO3 (BF-BT) is considered a promising candidate for high-temperature piezoelectric materials owing to its high Curie temperature ([Formula: see text]C) and good electromechanical properties. In this work, the hydrothermal synthesis method was used to prepare the precursor powders of BiFeO3 and BaTiO3, and then the mixed powder compacts with the chemical composition of 0.7BF–0.3BT were sintered under pressureless conditions. The influence of the hydrothermal reaction times (12–24[Formula: see text]h) of BiFeO3 on the structures and electric properties of the sintered ceramics was instigated. First, all the samples synthesized with the tetragonal BaTiO3 and BiFeO3 powders were identified with relatively stable dielectric properties. As the hydrothermal reaction time to synthesize BiFeO3 increased, the dielectric properties as well as the temperature stability of the 0.7BiFeO3–0.3BaTiO3 ceramics also improved. At the condition of a hydrothermal reaction time of 24[Formula: see text]h, the sample obtained possesses both the lowest temperature coefficient of dielectric constant ([Formula: see text]C between RT and [Formula: see text]C) and the highest Curie temperature ([Formula: see text]C at 100[Formula: see text]kHz). Moreover, at high temperatures, it exhibits a higher AC impedance than others. The calculating result based on the resistive constant-phase-element model (R-CPE) circuit model showed that the grain boundary of the 0.7BF–0.3BT ceramics contributes more resistance to the conductivity at high temperatures. In summary, the hydrothermal reaction proved to be a useful way that achieves the preparation of single-phase 0.7BF–0.3BT ceramics with improved electrical properties.

Dielectric and Structural Properties of the Hybrid Material Polyvinylidene Fluoride-Bacterial Nanocellulose-Based Composite.

In the search for environmentally friendly materials with a wide range of properties, polymer composites have emerged as a promising alternative due to their multifunctional properties. This study focuses on the synthesis of composite materials consisting of four components: bacterial nanocellulose (BNC) modified with magnetic Fe3O4, and a mixture of BaTiO3 (BT) and polyvinylidene fluoride (PVDF). The BT powder was mechanically activated prior to mixing with PVDF. The influence of BT mechanical activation and BNC with magnetic particles on the PVDF matrix was investigated. The obtained composite films' structural characteristics, morphology, and dielectric properties are presented. This research provides insights into the relationship between mechanical activation of the filler and structural and dielectric properties in the PVDF/BT/BNC/Fe3O4 system, creating the way for the development of materials with a wide range of diverse properties that support the concept of green technologies.

Electromagnetic wave absorption properties of Ni0.5Zn0.5Fe2O4–BaTiO3–epoxy composites

Composites consisting of ferrimagnetic spinel ferrite Ni0.5Zn0.5Fe2O4 (ZNF) and ferroelectric BaTiO3 (BT) powders embedded in epoxy (10 wt%) were synthesized and analyzed for their electromagnetic (EM) wave absorption properties. The ZNF and BT powders were combined in weight ratios of 1-x: x, where x = 0, 0.1, 0.2, 0.3, 0.4, and 1.0. With increasing x, the height of the complex permittivity (ε′ and ε″) spectra increased, while the height of the complex permeability (μ′ and μ″) spectra gradually decreased. The reflection loss (RL) value, indicative of EM absorption efficiency, was calculated using measured ε′, ε″, μ′, and μ″ data. Apart from the BT–epoxy sample (x = 1.0), which exhibited no magnetic loss mechanisms, the EM wave absorption characteristics in the NZF-BT-epoxy composites were predominantly influenced by magnetic loss mechanisms, as reflected in the μ″ values. The incorporation of BT modified the impedance matching conditions, causing the frequency at which maximum EM wave absorption indicated by the minimum RL (RLmin) occurs to shift to lower frequencies. The most remarkable EM wave absorption performance was observed for the sample with x = 0.4, where RLmin reached −70 dB. Notably, the samples with x values ranging from 0 to 0.4 demonstrated outstanding EM wave absorption capabilities within the radar frequency range of L and S-bands (1–4 GHz). Furthermore, the EM wave absorption bandwidth (Δf), representing the frequency range where RL < -10 dB, was 8.3 GHz (4.5–12.8 GHz) for the x = 0 sample. However, this bandwidth decreased to 2.6 GHz (5.0–7.6 GHz) for the x = 0.4 sample. Although the addition of BT led to a reduction in the EM wave absorption bandwidth compared to the NZF–epoxy composite (x = 0), it enabled the tuning of the absorption band towards lower frequencies, particularly emphasizing excellent EM wave absorption in the L-band.

Controlling Composite TiO2 Powder Characteristics in the Solid-State Synthesis of BaTiO3 Powders for Improved Sintering and Permittivity: A Comparative Study

In this study, the anatase–rutile phase fraction of TiO2, which would play a vital role in the solid-state synthesis of BaTiO3, was controlled to form a composite phase. The composite TiO2 was applied to a solid-state synthesis reaction, and the tetragonality, dielectric properties, and microstructure of the resulting BaTiO3 powders were analyzed under different synthesis conditions of TiO2. Furthermore, a comparative analysis of solid-state-synthesized BaTiO3 powders prepared using anatase, rutile, and mixed (anatase + rutile) TiO2 was performed to elucidate the mechanism of improvement in the sintering behavior and dielectric properties of the BaTiO3 powder synthesized using the composite TiO2. As a result of applying composite TiO2, BaTiO3 powder with excellent tetragonality was synthesized. In addition, it is effective in powder growth and the control of powder morphology, so sintering and dielectric properties can be improved at relatively low temperatures.

Electrical performance enhancement of a triboelectric nanogenerator based on epoxy resin/BaTiO3 by Al nanopowder addition for low power electronic devices

Triboelectric nanogenerators (TENGs) are crucial for applications such as smart sensors and bio-electronics. In the current work, we aimed for improved performance of TENGs with incorporation of BaTiO3 powder, which is known for its strong ferroelectric properties, combining it with epoxy resin to improve the flexibility of our devices. We observed that our TENGs can operate for over 24 000 cycles with no degradation of function. Additionally, we improved the electrical performance of the TENGs by incorporating various aluminum concentrations that change the electronic properties in the form of mixed epoxy resin, BaTiO3, and Al nanopowders. To identify the optimum conditions for the best performance, we analyzed the electrical characteristics and material properties by employing scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffractometry characterization techniques. Our findings suggest that this innovative combination of materials and optimization techniques can significantly improve the performance of TENGs, making them ideal for practical applications in various fields, such as low-power electronics, environmental monitoring and healthcare. Moreover, these enhanced TENGs can serve as sustainable and dependable energy sources for various applications.

Low voltage thick-film electroluminescent device with evaporated ZnS:Mn and spin coated BaTiO3 dielectric layer

In a thick-dielectric electroluminescent (TDEL) device, which is a variation of thin-film electroluminescent devices, one of the insulation layers is replaced by a thick-film dielectric layer. High brightness and reliability are the features of TDEL owing to a higher withstanding voltage of the thick-film dielectric layer. This paper presents a new type of TDEL with a bottom emission structure. The thick-film dielectric layer was manufactured by spin coating using an ink material, which is a mixture of BaTiO3 powder and a binder resin. The thicknesses of the phosphor and dielectric layers were minimized to reduce the operating voltage. A threshold voltage as low as 50 V and a maximum luminance of 1000 cd/m2 were obtained at 60 V.

Gdを添加したBaTiO&lt;sub&gt;3&lt;/sub&gt;-(Bi&lt;sub&gt;1/2&lt;/sub&gt;K&lt;sub&gt;1/2&lt;/sub&gt;)TiO&lt;sub&gt;3&lt;/sub&gt;系無鉛高温用PTCR材料の作製

Fabrication of high Curie point (Tc) PTCR materials using BaTiO3 (BT)-(Bi1/2K1/2)TiO3 (BKT) ceramics was investigated. Fine powders of BT, which was synthesized by hydrothermal process, were used as starting materials. BT powders, Bi2O3, KHCO3, TiO2 and Gd(NO3)3 (water solution) were mixed with (C2H5O)4Si by wet milling for 24 h. After drying, the powders were pressed into disks, which were diameter of 20 mm and thickness of 2 mm. These disks were sintered at 1130 – 1280 °C for 2 h in air. The samples containing 5 – 7 mol% BKT have the room temperature resistivity lower than 600 Ωcm, PTCR jump higher than 2.4 order of magnitude, and Tc higher than 175 °C. Especially, the sample containing 6 mol% BKT has the room temperature resistivity of 270 Ωcm, PTCR jump of 2.4 order of magnitude, and Tc of 185 °C and it was the excellent high Tc lead-free PTCR materials which was fabricated by firing in air.