XRD studies on hydrothermally synthesised BaTiO3 from TiO2–Ba(OH)2–NH3 system (original) (raw)

Hydrothermal Synthesis of Barium Titanate: Effect of Titania Precursor and Calcination Temperature on Phase Transition

Industrial & Engineering Chemistry Research, 2008

Nanosized barium titanate powders were synthesized by a hydrothermal method. The effect of titania precursors on the phase transition of BaTiO 3 with respect to Ba/Ti ratio, reaction temperature, reaction time, and calcination temperature was investigated. The synthesized materials were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. BaTiO 3 in pure cubic phase with spherical morphology was observed with a lower calcination temperature, Ba/Ti ratio, reaction temperature, and time. Increase in the tetragonal phase was ascertained in treatments at higher reaction temperature with a longer reaction time. The lattice hydroxyl release is believed to be the reason for tetragonality at high reaction and calcination temperatures. To prepare tetragonal BaTiO 3 using HClO 4 -TiO 2 , the optimum synthesis conditions viz., Ba/Ti ratio, reaction temperature, and reaction time, are 1.2, 160°C, and 3 h, respectively, at a calcination temperature of 1150°C. The reaction time and reaction temperature for the cubic-tetragonal phase transformation of BaTiO 3 shifted toward shorter reaction time and lower reaction temperature when TiO 2 was synthesized by hydrolysis using HClO 4 as the acid catalyst.

X-ray diffraction and microstructural studies on hydrothermally synthesized cubic barium titanate from TiO 2–Ba(OH) 2–H 2O system

Materials Letters, 2007

In our earlier studies synthesis of pure barium titanate (BT) from TiO2–Ba(OH)2–NH3 system was reported. This work describes a novel route for preparing cubic barium titanate from TiO2–Ba(OH)2–H2O system without addition of any mineraliser. The experimental parameters varied were: reaction time (half-an-hour to 3 h), reaction temperature (80 to 150 °C) and [Ba/Ti] ratio (0.92 to 1.64). The progress of reaction for formation of BT was monitored by analyzing the X-ray diffraction data obtained under different processing conditions. Mono-phasic barium titanate powder having a mean crystallite diameter (MCD) of 26 nm along (101) plane was formed when the reaction was carried out for 3 h at 150 °C. The estimated strains on the planes of the BT nano-crystals were found to be negligible. The microstructure of pure BT showed the particles to be of single crystallite nature with average size matching with the MCD value calculated from the XRD data.

Synthesis of Barium Titanate from Aqueous Solution of Barium Acetate and Titanium Dioxide Precursors

In this study, BaTiO 3 has been prepared from aqueous solution of barium acetate and titanium dioxide mixture. After drying, the barium titanate was obtained through solid state reaction. The thermal analysis TG-DTA and XRD techniques were used to study the formation of BaTiO 3 and the mechanism of formation as well. The effects of powder activation, calcination temperature and time on the formation of barium titanate were studied. It was found that, the use of barium acetate retarded the formation of BaTiO 3 and increased the temperature at which the reaction is completed. However, the coating process offered by this synthesis method for unmilled powder might be very useful in producing BaTiO 3 powder having core shell morphology, where the BaTiO 3 core is surrounded by a thin layer of Ba 2 TiO 4 as a shell.

Effect of temperature, time and particle size of Ti precursor on hydrothermal synthesis of barium titanate

Materials Science and Engineering B-advanced Functional Solid-state Materials, 2008

Barium titanate (BaTiO 3 ) nanopowder is synthesized using two TiO 2 powder precursors with different particle sizes and barium hydroxide via hydrothermal route. Effect of temperature, time and particle size is studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. Crystallite size of barium titanate is observed to decrease with increasing temperature, while morphology of obtained BaTiO 3 changed from porous irregular shape at lower reaction temperature (90 • C) to compact facetted shape at higher reaction temperature (150 • C). TEM observation of low reaction temperature samples (60 • C) supports in situ transformation or short range dissolution-precipitation reaction mechanism. The fine grained TiO 2 (∼25 nm) precursor reacted faster than coarse grained TiO 2 (∼110-125 nm) precursor. Reaction rate may depend on size of TiO 2 precursor particles. The phase of obtained BaTiO 3 in all samples is found to be cubic.

Preparing of Barium Titanate Using Chemical Method and Studying of its Structural Properties

Single crystalline BaTiO 3 (BT) was prepared using TiCl 4 , BaCl 2 and oxalic acid. The structure of the prepared nanocrystalline BT powders were a tetragonal perovskite according to XRD and HRTEM analysis. Annealing powder to 750 o C show that pure BT phase was formed according to XRD, TG, and FTIR spectroscopy. The TEM images of the prepared powder reveal spherical morphology of BT, while a finger twin, dendritic and embryo shape are observed of BT powder calcined at 230, 530, and 750 o C respectively. SAED and HRTEM images showed a high crystalline BT powder and a single crystalline BT respectively.

Advances in the synthesis, characterizations and applications of barium titanate. A review

Dutse Journal of Pure and Applied Sciences, 2023

Barium titanate (BaTiO3) is a compound that has a structure called perovskite. Synthesis of BaTiO3 can be done by employing separate methods. BaTiO3 has four polymorphs which are cubic, tetragonal, orthorhombic and rhombohedral, depending on the temperature, it has a tetragonal structure at ambient temperature. This paper aims to review different synthesis methods of BaTiO3, these techniques can be used in the process of making ceramics as a molding material and also as an intermediate between thin films of metal oxides in various applications. The characterization techniques mostly used in determining the lattice constant, crystal structure functional group, morphology, elemental compositions and electrical properties, of the nanomaterial, including the various applications of BaTiO3 which includes modern electronic appliances and electrical power systems, the Multilayer Ceramic Capacitors (MLCs), biological, and microwave absorption, due to their piezoelectric and dielectric properties are reviewed.

Hydrothermal preparation of barium titanate from barium-titanium acetate gel precursors

Journal of the European …, 1991

from Abstract Clear, transparent gels' of BaTi acetate have been prepared from titanium tetrabutylate (TBT), Ba acetate aqueous solution, isopropanol and acetic acid. Inl?ared spectroscopy and transmission electron microscopy (TEM) of such gels revealed linked clusters oJ" polymer Ti oxyacetate with surface adsorbed Ba acetate. Spray dried Ti oxyacetate has been .found to have the stoichiometric composition 1720 3 [CH3C0012. Calcination of BaTi acetate gels to BaTiO 3 in air turned out to be a less.favourable preparative route, because stable intermediate carbonate phases were Jormed. Corresponding to the high su@tce area and fine dispersion of Ba and Ti, BaTi acetate gels are highly reactive precursors .[or hydrothermal synthes'is of BaTiO 3. Nearly quantitative (>99.7%) chemical reactions were obtained without using Ba excess at processing. TEM provided interesting in[brmation about the chemical mechanisms of hydrothermal processing.

Synthesis and Characterization of Barium Titanate by Solid-State Reaction

Materials Science Forum, 2014

Solid-state reactions were used to synthesize pure and doped barium titanate powder. Barium titanate formation with tetragonal perovskite structure was detected by X-ray diffraction and occurred at a temperature above 700°C for pure powder and 500°C for doped powder. However, quite crystalline samples were observed only at 800oC and 600°C for pure and doped barium titanate, respectively, what made the refinement of the synthesized powders possible. They were characterized by X-ray diffraction and Fourier transform infrared spectroscopy and scanning electron microscopy. X-ray diffraction data was analyzed by using the Fullprof Rietveld refinement approach, Thompson-Cox-Hastings pseudo-Voigt with function. The refinement method was effective in the study of the temperature influence on the microstructure of the analysis of pure and doped barium titanate.

Solid-State Synthesis of Ultrafine BaTiO3 Powders from Nanocrystalline BaCO3 and TiO2

Journal of the American Ceramic Society, 2005

Barium titanate has been prepared by solid-state reaction of nanocrystalline TiO 2 (70 nm) with BaCO 3 of different particle size (650, 140, and 50 nm). The results give evidence of a strong effect of the size of BaCO 3 in the solid-state synthesis of barium titanate. The use of nanocrystalline BaCO 3 already leads to formation of the single-phase BaTiO 3 after calcination for 8 h at 8001C. The final powder consists of primary particles of % 100 nm, has a narrow particle size distribution with d 50 5 270 nm, and no agglomerates larger than 800 nm. For the coarser carbonate, 4 h calcination at 10001C are required and the final powder is much coarser. Solid-state reaction of nanocrystalline BaCO 3 and TiO 2 represents an alternative to chemical preparation routes for the production of barium titanate ultrafine powders.