Titanate Ceramic Powder Research Articles

Influence of Sintering Temperature on Microstructure and Dielectric Properties of Strontium Calcium Titanate (Sr<sub>0.9</sub>Ca<sub>0.1</sub>TiO<sub>3</sub>) Ceramics

Strontium Calcium Titanate (Sr0.9Ca0.1TiO3) ceramic powders were synthesised using a solid sintering technique and were uniaxially pressed and sintered at different temperatures of 1100 °C, 1150 °C, 1200 °C, 1250 °C, and 1300 °C for three hours. Physical, phase, microstructure and dielectric properties were studied. Perovskite Cubic Strontium Calcium Titanate phase was crystallized. With an increase in sintering temperature, the density and grain size of Sr0.9Ca0.1TiO3 ceramics increased. Grain boundaries were observed in the microstructure of Sr0.9Ca0.1TiO3 sintered at higher temperatures. At room temperature, the dielectric constant and dielectric loss are observed to increase with the increase in sintering temperature. AC conductivity enhanced with sintering temperature.

Effect of novel aluminium titanate on mechanical, thermal and ablation performance behavior of carbon fiber reinforced phenolic resin composites

AbstractThermal Protection Systems (TPS) protect re‐entry space vehicles from the harsh heating they encounter when hypersonically flying through a planet or the earth's atmosphere. Carbon fiber‐reinforced phenolic resin composites were widely used for the thermal barrier structure of aerospace re‐entry vehicles. A Novel Aluminium Titanate (Al2TiO5/AT) micro powder‐modified Polyacrylonitrile (PAN) based Carbon Fiber Fabric‐Resorcinol Phenol Formaldehyde Resin (C‐PR) (AT‐C‐PR) composites are well prepared to meet the requirements of TPS. The AT may act as an insulating layer and anti‐ablative material due to its excellent thermal shock resistance in TPS. To understand the effectiveness of AT content on density, barcol hardness, interfacial interactions, thermal conductivity, and thermal stability, the C‐PR composites were produced with and without loading of AT with various weight percentages, namely 0 wt% (C‐PR), 1,3, and 5 wt% (AT‐C‐PR) by hot compression molding method. The microstructural and elemental change of the composites were analyzed by microscopic and spectroscopic studies. Results suggested that the Interlaminar Shear Strength (ILSS) of the composites was increased by about 14% at 1 wt% of AT loading. Mass, Linear Ablation Rates (MAR, LAR), and back‐face temperature of C‐PR and AT‐C‐PR composites were decreased to 0.15128 g/s, 0.01233 mm/s, and 405°C, respectively by loading of AT up to 1 wt%. The thermally ablated composites were also evaluated for their crystallographic phase changes. The work provided an effective way to improve the thermo‐mechanical and ablation performance characteristics of the AT‐C‐PR composites that can be potentially used in TPS of re‐entry vehicles.Highlights This investigation utilized innovative Al2TiO5/Aluminium Titanate (AT) ceramic powder as a filler in reinforcing Phenolic Resin (PR) with PAN‐based Carbon Fiber (C). It examined the impact of various loadings of AT in C‐PR composites (AT‐C‐PR) on their physical, mechanical, thermal, and anti‐ablation properties. The AT‐C‐PR composites exhibit reduced density, lower thermal conductivity, and enhanced ILSS (31 MPa) compared to the C‐PR composites. Optimal ablation resistance and thermal stability were achieved with a loading of 1 wt% AT (Mass Ablation Rate: 0.15128 g/s and Linear Ablation Rate: 0.01233 mm/s) compared to the C‐PR composites. Microstructural and elemental analysis of the composites were conducted using microscopy and energy‐dispersive spectroscopy, revealing the presence of oxides and carbides on the ablated surface. The phase transition and alterations in microstructure, coupled with the oxidation of AT, have enhanced the ablation resistance and reduced the back face temperature of different weight percentages of AT‐C‐PR composites, such as 1 wt% AT (413°C), compared to the C‐PR composites (704°C).

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.

A soft piezoelectric elastomer with enhanced piezoelastic response

This work aims to study, develop, and validate a soft piezo-polymer with enhanced piezo-elastic response and easy castable in a free shape through a single and easy process. The work identified a novel formulation for soft piezopolymers based on ambient temperature polymerizable silicone rubber, easily fabricable in 3D printed plastic moulds. Combining polymerizable silicone with a barium titanate (BaTiO3) ceramic powder and defining a detailed fabrication procedure of casting, curing and high voltage poling, we defined how to obtain a promising soft piezoelectric elastomer for countless sensing applications. This study includes information about the mould design used to realize, cure and polarize cylindric elastomeric specimens. This piezopolymer stands out for its flexibility, softness, easy fabrication at ambient temperature and obtainability in multiple shapes and bulky 3D geometries. Finally, we investigated different configurations of the piezopolymer formulation analysing the powder concentration and voltage polarization effects over the mechanical, piezoelectric and morphological characteristics. The specimens exhibit a high induced polarization with values up to 22.5 pC N−1, comparable with poled -phase polyvinylidene difluoride. We finally underlined limits encountered in the most extreme configurations.

Preparation and analysis of dielectric behaviour of BCZT based flexible PVDF polymer composite membrane

In this paper, Barium Calcium Zirconium Titanate (Ba0.86 Ca0.14 Zr0.05 Ti0.95 O3) ceramic powder samples were prepared by the solid-state reaction process. After that, it is mixed with polyvinylidene fluoride (PVDF) to form composite membrane, which is fabricated using the solution cast method. Two membranes were prepared with 15 wt% and 50 wt% filler concentrations of BCZT with PVDF matrix. Dielectric behaviours of prepared composite membrane are analyzed, and these various analyses of composite film are also compared with each other. In this, we see that the increasing addition of lead-free based inorganic filler with an organic PVDF matrix enhanced the dielectric constant five times for the frequency 1KHz and reduction in the losses and increases the conductivity of the composite as the filler weight percentage increased. These fabricated composite membrane can be used for wearable biomedical devices, soft robotics and flexible energy storage capacitors.

Effect of heat treatment on dielectric and ferroelectric properties of BST ceramics

Barium Strontium Titanate (Ba0.9Sr0.1TiO3) ceramic powders were prepared by solid-state sintering technique and were uniaxially pressed and sintered at different temperatures of 1000 °C, 1050 °C,1100 °C, 1150 °C and 1200 0C for three hours. The physical, phase composition, microstructure, dielectric and ferroelectric properties of the BST ceramics were investigated. BaTiO3 was the major crystalline phase formed in ceramics. With the increase in the sintering temperature, the density was observed to be increased. Grain boundaries were clearly observed in the micrographs of FESEM for the ceramic samples sintered at high temperatures. Ferroelectric hysteresis was observed for the BST ceramic samples. At room temperature, the dielectric constant of the BST ceramic samples was observed to be increased with the increase of sintering temperature.

Silane-treated BaTiO3 ceramic powders for multilayer ceramic capacitor with enhanced dielectric properties

Silane/ceramic combination provides the composites with several advantages from the advancements of new ceramic composite materials with good thermal conductivity, high mechanical and dielectric properties have wide significant applications in electrical and electronic industries. In this study, to enhance the dispersibility of dielectric barium titanate (BaTiO3) ceramic powder and additives for the fabrication of multilayer ceramic capacitors (MLCCs), surface treatment of the precursor of ceramic powder was performed using silane coupling agents. Dielectric ceramic sheets fabricated from ceramic powders that had been surface-treated with different amounts of N-[3-(trimethoxysilyl)propyl]aniline (TMSPA) which increased the surface gloss. In particular, the dielectric properties of the multilayer ceramic sheet fabricated by stacking sheets from the TMSPA-treated ceramic powder sintering at 1200 °C, it was confirmed that the dielectric constant increased from 881 to 2382 and the dielectric loss dropped from 1.96 to 1.34% with utilization of the TMSPA treatment. The physical and dielectric properties of the TMSPA-treated multilayer ceramic sheet were also determined by Fourier-transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, glossmetry, and electrochemical impedance analysis. The results revealed that the TMSPA-modified BaTiO3 surfaces considerably increased the dielectric property of the fabricated nanocomposite.

Synchrotron radiation X-ray diffraction evidence for nature of chemical bonds in Bi4Ti3O12 ceramic powders and grain-orientation mechanism of their films formed by aerosol deposition method

Structural characteristics of a bismuth titanate (Bi4Ti3O12, BiT) ceramic powder material and the polycrystalline film formed by the aerosol deposition (AD) method are investigated by synchrotron-radiation X-ray diffraction. The BiT powders without clear plate-like shapes are prepared as stating powders for the film deposition. The electron charge density analysis demonstrates that the particular BiT powders synthesized in this study have the same layered crystal structure as well-known BiT powder materials. The c-oriented polycrystalline film is deposited at room temperature onto a glass substrate without any heat treatment by the AD method. The high orientation of the BiT as-deposited AD film is attributed to the layered crystal structure essentially originated from the anisotropic nature of chemical bonds in the BiT crystal rather than the shapes of particles of the starting powders.

Piezoelectric studies of PEDOT:PSS incorporated BaTiO3/ PDMS micro-generator

Different naturally occurring and wasted vibrational energy forms can be converted into electrical output with the help of proper Piezoelectric Energy Harvesting Systems (PEHS). Even though there are many attractive features of piezoelectric materials like: high energy density, light weight, compactness, the one main disadvantage is low current density. In this work flexible piezoelectric micro-generators suitable for PEHS were made with simple, low cost hydrothermal method with BaTiO3/PDMS micro-composites. The ceramic polymer micro-composite was developed by mixing of Barium Titanate (BaTiO3) ceramic powder with polydimethylsiloxane (PDMS) polymer in 4:1 wt ratio. The fabricated device is flexible, heat resistant and stretchable with good output voltages upon the application of vibrational energy. The short circuit current is found to be improved by incorporating 0.01 wt% of poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid)(PEDOT: PSS) to the BaTiO3/PDMS composite material. The Piezo electric characteristics of both materials are compared and the PEDOT: PSS incorporated material is found to have better output current density. The newly developed micro-generator has improved piezoelectric characteristics.

Fabrication of Piezoelectric Composites Using High-Temperature Dielectrophoresis

In this paper, we present a method to create a highly sensitive piezoelectric quasi 1–3 composite using a thermoplastic material filled with a piezoelectric powder. An up-scalable high-temperature dielectrophoresis (DEP) process is used to manufacture the quasi 1–3 piezoelectric polymer-ceramic composites. For this work, thermoplastic cyclic butylene terephthalate (CBT) is used as a polymer matrix and PZT (lead zirconium titanate) ceramic powder is chosen as the piezoelectric active filler material. At high temperatures, the polymer is melted to provide a liquid medium to align the piezoelectric particles using the DEP process inside the molten matrix. The resulting distribution of aligned particles is frozen upon cooling the composite down to room temperature in as little as 10 min. A maximum piezoelectric voltage sensitivity (g33) value of 54 ± 4 mV·m/N is reported for the composite with 10 vol% PZT, which is twice the value calculated for PZT based ceramics.

Effect of fillers size on the dielectric and piezoelectric characteristics of a piezoelectric composite

Recent trends in electromechanical conversion using alternative materials, have demonstrated the advantages of using piezoelectric composites for energy generation. There have been several papers on ceramic/polymer composites in which the fillers have high piezoelectric constant. Basically, the energy harvested depends on the proportion of the piezoelectric properties of composite. The fillers size within the composites is also an important criterion of the composites properties. Thus, in this paper 0–3 composites, made of lead zirconate titanate (PZT) ceramic powder and polyurethane (PU) were prepared. Different sizes of ceramic grains were used: grains with average size of 10 μm, size under 80 μm and size under 100 μm. Sizes of the PZT grains was determined according to the homogenization efficiency of the composite. Piezoelectric (piezoelectric coefficient d33) and dielectric properties (dielectric constant) were investigated. They have shown an interesting improvement with the increasing grains size up to 20 pC/N and 100, respectively. In order to understand the composite behavior on the microscopic scale, a simulation was carried out by mean of a finite element method (FEM) software. Finally, an estimation of the harvested voltage was modeled according to the grains size.

Enhanced pyroelectric property of PMN–PT/P[VDF–TrFE] thick film by optimizing poling temperature

Lead magnesium niobate–lead titanate (PMN–PT) ceramic powder and Poly[VinyliDeneFluoride-co-TriFluoroEthylene] (P[VDF–TrFE]) have been used to fabricate 0–3 composites thick films on ITO substrates by tape casting. The phase structure and grain size of PMN–PT were analyzed by XRD and SEM. The distribution of ceramic powder in polymer matrix was characterized by SEM. In order to find out the optimal poling temperature, dielectric-temperature spectrums of the composite films were measured to calculate the electric field applied to the ceramic phase (Ec). Finally, PMN–PT/P[VDF–TrFE] composite films were polarized by one-step polarization under optimized polarization temperature and their pyroelectric constant were compared with these of samples poled using conventional two-step polarization method. The results showed that the pyroelectric coefficient increases to 58.6 μC m−2 K−1 at a ceramic mass fraction of 55% at the optimized polarizing temperature 110 °C.

Physical and electrical properties of SrTiO3and SrZrO3

Perovskite type oxide strontium titanate (SrTiO3 ) and strontium zirconate (SrZrO3 ) ceramic powder has been synthesized using conventional solid state reaction method. The powders were mixed and ground undergone calcinations at 1400°C for 12 h and sintered at 1550°C for 5h. X-ray Diffraction exposes physical properties SrTiO3 which exhibit cubic phase (space group: pm-3m) at room temperature meanwhile SrZrO3 has Orthorhombic phase (space group: pnma). The electrical properties such as dielectric constant (er), dielectric loss (tan δ), and conductivity (σ) were studied in variation temperature and frequency. High dielectric constant of SrTiO3 and SrZrO3 were observed at 10 kHz for both samples about 240 and 21 respectively at room temperature. The dielectric loss of SrTiO3 and SrZrO3 is very low loss value approximately 0.00076 and 0.67512 indicates very good dielectric.

Pure and La<sup>3+/</sup>Nd<sup>3+</sup> Doped SrTiO<sub>3</sub> Powders Obtained by Solid State Reaction and Microwave Assisted Hydrothermal Synthesis

Strontium titanate ceramic powders (SrTiO3), pure and doped with lanthanum (La3+) and neodymium (Nd3+), were synthesized by solid state reaction (SSR) and microwave assisted hydrothermal technique (MHT). For SSR, a mixture of SrCO3, TiO2, La2O3and Nd2O3oxides was performed in stoichiometric ratio, to produce SrTiO3(STO), Sr0.96La0.04TiO3(STO-04La), Sr0.96Nd0.04TiO3(STO - 04Nd) and Sr0.96La0.02Nd0.02TiO3(STO-02La02Nd), in a ball mill, for 3.5 h. This mixture was dried at 70°C for 24h. This powder was calcined at 1150°C for 2h in a conventional oven. For MHT synthesis, Ti (C4H9O)4, SrCO3, La2O3and Nd2O3precursors were solubilized in nitric acid (10M), in stoichiometric proportions to form STO , STO-04La, STO-04Nd and STO-02La02Nd. This solution was precipitated adding NH4OH (10M). Quota of 2g of precipitated powder was then dried in an air oven at 70°C for 24 hours, and then added to 40 ml of a KOH solution (10M). These suspensions were subjected to MHT for 1h, at 120°C. The ceramic powders obtained by the two routes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The crystallite size was calculated by Scherrer method and from SEM image, linear intercept method for both the SSR and MHT powders was used to measure the particles size, which show the increase of particles size related to the cation substitution.

Microstructure and dielectric properties of ST ceramics prepared by the sol–gel combustion technique with chitosan addition

The effect of chitosan content and sintering temperature on phase formation, microstructure, physical properties and dielectric properties were studied. Strontium titanate (ST) ceramic powders were synthesized by the sol–gel combustion method with various chitosan contents (1, 3, 5, 7 and 10mol%) addition. The synthesized samples were characterized by XRD, FT-IR, SEM and TEM. The results showed that the obtained ST powders were uniform in size with a cubic perovskite structure. The highest percentage of the perovskite phase and well crystallinity were exhibited at 3mol% chitosan addition, while the perovskite phase decreased with increasing chitosan content. It was demonstrated that the chitosan adding process is beneficial to the homogenously distributed in the ST preparation. The highest density of the sintered ST ceramic was 4.3g/cm3 (84% of theoretic value) when sintered in the range of 1200–1300°C for 4h and had an average grain size of approximately 437±61.4nm. The high dielectric constant of ST ceramics sintered at 1200°C for 4h was 504 (at 1kHz).

Study of Phase Transitions and Response of Dielectric Behavior of Pb1–1.5xLaxTiO3 Ceramics

Polycrystalline samples of ferroelectric perovskite type lanthanum doped lead titanate, Pb1–1.5xLaxTiO3 (PLT) with x ranging from 0.00 ≤ x ≤ 0.3 ceramic system have been synthesized through the modified solid-state reaction technique. One of the objectives of this work was to optimize carefully the process variables which influence the structural and microstructural properties of the samples prepared. X-ray diffraction studies have been used to follow the evolution of the structural phases that occur with the increase of lanthanum content. The sharp peaks observed in XRD patterns and the absence of any impurity peaks confirmed the formation of single phase compounds. The analysis of the X-ray diffraction patterns for the samples with 0.00 ≤ x ≤ 0.2 confirmed the tetragonal phase formation. For x = 0.3 the observed X-ray diffraction peaks confirmed the presence of cubic phase as also evident from the absence of splitting of (101 110) and (002 200) peaks. The average linear particle sizes for all the compositions estimated using Scherrer's formula lie in the range 230–570 nm. The grain sizes of the lead lanthanum titanate ceramic powders increases with the increase of lanthanum content. The grain morphology and size were directly imaged using scanning electron microscopy (SEM) and the average grain size was determined by using a mean linear intercept method. Detailed studies of dielectric constant (ϵ) and tangent loss (tan δ) as a function of frequency (5 Hz–13 MHz) at room temperature (RT) and temperature (RT-900 K) suggest that compounds undergo ferroelectric-paraelectric phase transition of diffuse type. The value of diffusivity γ is extracted from the ln (1/ϵ−1/ϵmax) vs. ln (T−Tmax)γ plots and the values of γ vary between 1.18 to 1.75, which confirm that diffuse phase transition occurs in the lead lanthanum titanate (PLT) system. The results of differential scanning calorimetry (DSC) study also support the phase transition temperature observed in the dielectric measurements.

Microstructure and Dielectric Properties of Bi Substituted PLZMST Ceramics

Bismuth (Bi) and lanthanum (La) doped lead manganese antimoine zirconate titanate (PZMST) ceramic powders have been synthesized by high temperature solid-state reaction method. Preliminary X-ray structural analysis of the compounds shows the formation of tetragonal structure. Scanning electron micrographs (SEM) shows a uniform grain distribution and grain size of the order of ~2.28 μm. Detailed dielectric studies of the Pb0.95(La1-z Biz)0.05[(Zr0.6Ti0.4)0.95(Mn1/3Sb2/3)0.05]O3 samples as a function of the temperature (from 25°C to 450°C) at frequency 1 kHz suggest that the compounds undergo a diffuse phase transition. The transition temperature shifts increase with increasing the Bi ratio. Diffusivity (γ) study of phase transition of these compounds provided its value from 1.59 to 1.78 indicating the degree of the disordering in the system.

DIELECTRIC BEHAVIOR OF NANO BARIUM TITANATE FILLED POLYMERIC COMPOSITES

Rapid growth of electronic industry requires development of new materials that combine the high dielectric constant intrinsic to ferroelectric ceramic materials with easy processing characteristics of polymers. Ceramic-polymeric composites possess interesting properties for a variety of electronic applications including passive electronic devices. In fact, polymer-ceramic materials have drawn lot attention for use in microelectronic packaging, because they can give higher performance with lower cost, size and weight. In this work, attempts are made to prepare ceramic polymer composites followed by characterization of dielectric properties. The Barium Titanate ceramic powders are synthesized using the hydrothermal process. Crystal structure and crystallite size of particles are determined using X-ray diffraction. Silane treatment is carried out on Barium Titanate powder to increase its compatibility with polymer, followed with preparation of ceramic polymer composites. Epoxy and polyvinyledene fluoride (PVDF) polymers are used as matrices for preparation of the composites. The proportion of nanopowder is varied from 60 to 90 wt%. Dielectric properties such as volume resistivity, dielectric constant, dissipation factor are evaluated. Results indicate that the dielectric constant and dissipation factor vary between 18 -140 and 0.01 to 0.09, respectively as the relative ratio of polymer and silane modified Barium Titanate is varied. Specifically, at 90 wt% of 0.1 wt% silane modified Barium Titanate, the highest dielectric constant of 140 along with dissipation factor of 0.07 is obtained in the epoxy based system.

Influence of barium titanate content and particle size on electromechanical coupling coefficient of lead-free piezoelectric ceramic-Portland cement composites

The 0–3 lead-free piezoelectric ceramic-Portland cement composites were prepared by mixing and pressing the Portland cement (PC) and barium titanate (BT) ceramic powder. The influences of BT particle size and BT content on the electromechanical coupling coefficient (Kt) of the composites were investigated. The results indicate that the particle size of BT used to produce the composite under the conditions of the same BT content (at 50%BT) and fabrication technique has an influence on the Kt values. The electromechanical coupling coefficient was found to increase with the particle size of BT used where the values of Kt are found to be at 10.8% and 14.1% for composites with median particle size of 75μm and 425μm, respectively. Furthermore, Kt of composites increase with increasing content of BT (at the same particle size of 425μm) when the content of BT reaches 70%, Kt is 16.6%. In addition, the acoustic impedance of the composite also increase with an increase of BT content.

Performance of High-Permittivity Ceramic-Polymer Composite as a Substrate for UHF RFID Tag Antennas

A high-permittivity ceramic-polymer composite substrate is fabricated and proposed for its potential use in UHF RFID tags. The substrate is developed using high-permittivity Barium Titanate (BaTiO3) ceramic powder mixed with polydimethylsiloxane (PDMS) polymer. The resulting composite achieves a soft, hydrophobic, heat resistant, low loss, and flexible material with high dielectric constant. The percentage of the ceramic powder in the composite helps in achieving variable permittivity values. When this material is used as a substrate for a tag antenna, it will help the tag to be reduced in size, to conform to uneven or rough surface, and to be less vulnerable to breakage or other environmental damages. A small passive UHF RFID tag antenna is designed, fabricated, and attached to this type of composite substrate, to demonstrate the performance of this composite material.