Microwave Synthesis of BaTiO3 from BaCO3 and TiO2

2007 ◽  
Vol 336-338 ◽  
pp. 669-671
Author(s):  
Yan Yi Liu ◽  
Wei Pan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Oven ◽  
X Ray Diffraction ◽  
X Ray ◽  
Batio3 Powder ◽  
Domestic Microwave Oven ◽  
Intermediate Phases ◽  
Different Temperatures ◽  
Scanning Electron

BaTiO3 powder was synthesized from BaCO3 and TiO2 using a domestic microwave oven. The samples were synthesized under different temperatures with various holding times. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to examine the phase compositions and morphologies of the result samples. The main phase obtained at 950°C was BaTiO3, and the intermediate phases Ba2TiO4 and Ba4TiO9 were also detected. The pure, well-crystallized BaTiO3 powder could be obtained at 1050°C within 10 minutes and the particle size ranged from 300~500nm. In comparison with conventional synthesis, faster speed and finer grains could be achieved through microwave heating.

Effects of V2O5 on the synthesis of Ba2Ti9O20 powders

2005 ◽  
Vol 20 (10) ◽  
pp. 2741-2744 ◽  
Author(s):  
Huixing Lin ◽  
Wei Chen ◽  
Lan Luo
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Eutectic Liquid ◽  
X Ray ◽  
Intermediate Phases ◽  
Phase Pure ◽  
Scanning Electron

Phase-pure Ba2Ti9O20 powders were made by doping 3 wt% of V2O5 to a Ba:Ti = 2:9 molar composition, and the effects of the dopant on the phase formation were investigated. The study shows that BaTiO3, BaTi2O5, and BaTi4O9 were the intermediate phases before the formation of Ba2Ti9O20 for samples with or without V2O5. However, with V2O5 doping, the temperature at which Ba2Ti9O20 occurred were lowered from 1150 to 1050 °C and single phase Ba2Ti9O20 powders was easily obtained at 1150 °C for 2 h. Microstructure of the powders was examined by field emission scanning electron microscopy. No evidence of V2O5–Ba2Ti9O20 solid-solution was found by x-ray diffraction and energy-dispersive spectroscopy. The benefit of V2O5 to facilitate the Ba2Ti9O20 synthesis is most probably due to a vanadium-containing eutectic liquid phase which accelerates the migration of reactant species.

Study of the Influence of Temperature on the Optical and Structural Properties of Dolomite

2020 ◽  
Vol 74 (10) ◽  
pp. 1280-1286
Author(s):  
Lucas Train Loureço ◽  
Celso de Araujo Duarte ◽  
Dietmar William Foryta ◽  
Bruno Guimarães Titon ◽  
Eleonora Maria Gouvêa Vasconcellos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Treatment ◽  
X Ray Diffraction ◽  
Electron Dispersive Spectroscopy ◽  
Influence Of Temperature ◽  
X Ray ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The present work reports the results of structural and optical investigations in samples of natural dolomite, subjected to thermal treatment at different temperatures (500 ℃ to 700 ℃) and times (one up to three hours). The motivation is the evaluation of the changes that may occur in carbonaceous asteroids and meteorites, respectively, subjected to the action of the solar radiation and heated during the fall in the atmosphere. We carried out scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, optical reflectance and photoluminescence measurements

scholarly journals Electrical and microstructural properties of microwave sintered SnO2-based varistors

Cerâmica ◽  
2012 ◽  
Vol 58 (346) ◽  
pp. 151-157 ◽  
Author(s):  
P. S. Furtado ◽  
M. M. Oliveira ◽  
J. S. Vasconcelos ◽  
J. H. G. Rangel ◽  
E. Longo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Oven ◽  
Sample Holder ◽  
Microstructural Properties ◽  
Electrical Field ◽  
Heating Chamber ◽  
X Ray ◽  
Domestic Microwave Oven ◽  
Scanning Electron

An investigation was made of the microstructural and electrical properties of SnO2-based varistors microwave sintered at 1200 ºC, applying a heating rate of 120 ºC/min and treatment times of 10, 20, 30, 40, 50 and 60 min. The system used in this study was (98.95-X) %SnO2.1.0%CoO.0.05%Cr2O3.X%Ta2O5, where X corresponds to 0.05 and 0.065 mol%. Sintering was carried out in a domestic microwave oven (2.45 GHz) fitted for lab use. Silicon carbide was placed in a refractory vessel to form a heating chamber surrounding the sample holder. The pellets were examined by scanning electron microscopy, X-ray diffractometry, direct current measurements and impedance spectroscopy. The parameters of density, medium grain size, coefficient of nonlinearity, breakdown electrical field, leakage current, and height and width of the potential barrier were analyzed.

Study of Synthesis and Crystal Structure of Barium Cerate at High Temperatures

2017 ◽  
Vol 891 ◽  
pp. 473-477
Author(s):  
Renáta Verbová ◽  
Viktor Kavečanský ◽  
Pavel Diko ◽  
Samuel Piovarči
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Barium Cerate ◽  
X Ray Diffraction ◽  
Oxalate Precursor ◽  
X Ray ◽  
Different Temperatures ◽  
Average Size ◽  
Scanning Electron

Crystalline barium cerate was synthesized by oxalate coprecipitation from nitrates of barium and cerium [1]. The oxalate precursor prepared by chemical methods was calcined at different temperatures up to 950°C. The barium cerate was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction investigation enables the determination of the phases that originate at different stages of synthesis and the crystal structure of final barium cerate, as well. From XRD patterns the average size of coherent regions was estimated by using Halder-Wagner method [2]. Both size and shape of crystallites were also studied by scanning electron microscopy. It was found that crystallites of barium cerate arise within the initial particles of the oxalate precursor.

Research of Rough Structure of Superhydrophobic Film

2011 ◽  
Vol 287-290 ◽  
pp. 253-256
Author(s):  
Zhan Shen Zheng ◽  
Rui Jiao Li ◽  
Pei Qi Yan ◽  
Rong Yang ◽  
Peng Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Scanning Electron

Superhydrophobic film was fabricated mainly by ethyl silicate (TEOS) and ethanol (EtOH) using sol-gel method. SiO2 gel and samples coated with SiO2 sol were calcined at different temperatures, and their morphology and composition were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results indicate that increasing calcining temperature appropriately improved the bond of nanoparticles of film successfully. Furthermore, there were only amorphous SiO2 and hydroxyl existing in the calcined film which would be benefit for the further modification.

scholarly journals Структурные превращения в борате железа при высокотемпературном отжиге

2019 ◽  
Vol 89 (8) ◽  
pp. 1229
Author(s):  
С.В. Ягупов ◽  
Н.И. Снегирёв ◽  
К.А. Селезнева ◽  
Е.Т. Милюкова ◽  
Ю.А. Могиленец ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Iron Borate ◽  
X Ray ◽  
Different Temperatures ◽  
Scanning Electron

Surface morphology and crystal structure of iron borate, FeBO3, annealed at different temperatures, have been studied by scanning electron microscopy and X-ray diffraction analysis. The temperature range of structurally stability of iron borate has been determined. It has been established that in the range of temperatures 800–900°C recrystallization in the iron orthoborate Fe3BO6 phase, and more than 900°C − in α-Fe2O3 phase, occurs.

Microraman Spectroscopy and X-Ray Diffraction Studies of Ti-W-O Thin Films

1996 ◽  
Vol 441 ◽  
Author(s):  
Luigi Sangaletti ◽  
Elza Bontempi ◽  
Laura E. Depero ◽  
P. Galinetto ◽  
Silvio Groppelli ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Microraman Spectroscopy ◽  
Scanning Electron

AbstractThin films of the Ti-W-O system grown by r.f. reactive sputtering from a Ti-W (10%–90% weight) target have been studied by Raman and microraman spectroscopy, X-ray diffraction and scanning electron microscopy with the aim to investigate their microstructural and morphological properties. To this purpose, the kinetics of structural transformations at different temperatures (600 °C, and 800 °C) have been studied, and the effect of Ti on the WO3 lattice has been singled out. The results show that annealing at different temperatures induces a microstructural evolution from the amorphous phase of the as-deposited thin film to WO3 crystalline phases via an intermediate cubic disordered phase of WO3. The effect of Ti on this cubic phase and on the thin film morphology is also investigated with the aid of microraman and scanning electron microscopy analysis. The results show that two distinct phases arise upon long annealing treatments; namely, small crystallites belonging to the WO3 monoclinic phase are dispersed on a layer composed of a disordered cubic WO3 phase with a high Ti content.

scholarly journals Sintering of anorthite based ceramics prepared from kaolin DD2 and calcite

Cerâmica ◽  
2016 ◽  
Vol 62 (364) ◽  
pp. 317-322 ◽  
Author(s):  
S. Zaiou ◽  
A. Harabi ◽  
E. Harabi ◽  
A. Guechi ◽  
N. Karboua ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Raw Materials ◽  
Bimodal Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Powders ◽  
Different Temperatures ◽  
Scanning Electron

Abstract In this work, the preparation of anorthite based ceramics using a modified milling system and 80 wt% kaolin (DD2 type) and 20 wt% calcium oxide extracted from CaCO3 is shown. The choice of these raw materials was dictated by their natural abundance. Previous studies have shown that a simple and vibratory multidirectional milling system using a bimodal distribution of highly resistant ceramics can be successfully used for obtaining fine powders. The prepared samples were sintered at different temperatures ranging between 800 and 1100 °C. It has been found that the relative density of samples sintered at 900 °C for 1 h with a heating rate of 5 °C/min was about 96% of the theoretical density of anorthite (2.75 g/cm3). Finally, the prepared samples were also characterized by scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

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