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

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.

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.

Microstructure and Properties of Zirconia-Mullite Nanocomposites Obtained from Si-Al-Zr-O Amorphous Bulks Doped with CaO and MgO

2011 ◽  
Vol 142 ◽  
pp. 87-91 ◽  
Author(s):  
Xiao Ping Tan ◽  
Shu Quan Liang ◽  
Li Yuan Chai
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Treatment ◽  
Anisotropic Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Zirconia-mullite nanocomoposites were prepared from Si-Al-Zr-O amorphous bulk with diffrent content of CaO and MgO by two-step thermal treatment between 900 and 1200°C. The effects of the additives on the phase and microsturcture were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results show that the addition of CaO promotes cristobalite phase formation and the anisotropic growth of mullite grains. An indention micro-crack method was used to measure the fracture toughness of zirconia-mullite nanocomoposites. The results demonstrate that the fracture toughness increases with higher concentration of CaO. The improvement of fracture toughness is attributed to the anisotropic growth of grains.

Reactivity Towards O2 and NO of the Soot Formed from Ethylene Pyrolysis at Different Temperatures

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
M Pilar Ruiz ◽  
Alicia Callejas ◽  
Angela Millera ◽  
María U. Alzueta ◽  
Rafael Bilbao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gas Chromatography ◽  
Raman Spectroscopy ◽  
Residence Time ◽  
Formation Temperature ◽  
Influence Of Temperature ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The influence of temperature on the formation of soot from ethylene pyrolysis has been studied. Pyrolysis experiments were carried out in a quartz reactor in the 1000-1200 °C temperature range, for an inlet C2H4 concentration of 50000 ppmv and a gas residence time of 4552/T(K) seconds. Outlet gases were analyzed by gas chromatography and the amount of soot produced measured. The reactivity of the soot samples obtained towards O2 and NO was also studied. Results show that the higher the formation temperature, the less reactive the soot. The soot samples were further characterized using elemental analysis, scanning electron microscopy and Raman spectroscopy, in order to study their structural properties, and relate them to their reactivity. Additionally, a comparison of the reactivity towards NO between acetylene and ethylene soot samples obtained under similar conditions has been carried out. The soot samples obtained from ethylene pyrolysis present higher reactivity towards NO than the soot samples formed from acetylene.

Influence of Temperature and Alkaline Activation for Synthesis Zeolite A from Natural Kaolin

2017 ◽  
Vol 751 ◽  
pp. 410-416 ◽  
Author(s):  
Pimpreeya Thungngern ◽  
Phanwatsa Amnaphiang ◽  
Panuruj Asawaworarit ◽  
Vituruch Goodwin ◽  
Nuwong Chollacoop ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Second Step ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
Hydrothermal Technique ◽  
Influence Of Temperature ◽  
Alkaline Activation ◽  
X Ray ◽  
Scanning Electron

Zeolite A from natural kaolin have been successfully synthesized via calcination and hydrothermal. However, these techniques have one drawback since, the impurities in kaolin such as muscovite and quartz in the kaolin structure, which depend on temperature and alkaline activation. This work was separated into two steps, first step was used calcination technique, and second step was used hydrothermal technique. Reaction of temperature in the first step was studied the influence of temperature from 500°C to 800°C for 3 hours. In this step, kaolin transformed to metakaolin and remain the impurities. Next, reaction of alkaline activation in second step was studied about the influence of NaOH. The concentration of NaOH in hydrothermal was varied from 1M to 4M and mixed with metakaolin at 90°C for 72 hours. X-ray Diffraction Spectroscopy (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used for characterization. The solid products were formed to zeolite A at 1M NaOH hydrothermal with 500°C to 800°C calcination and it can be seemed good of euhedral structure at 700°C

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.

Sign in / Sign up

Export Citation Format

Share Document