Thermal conversion of gels to YBa2Cu3Ox, Bi2Sr2CaCu2Ox, and (Bi, Pb)2Sr2Ca2Cu3Ox and their decarbonization by low-temperature treatment with nitric acid

1996 ◽  
Vol 11 (1) ◽  
pp. 1-4 ◽  
Author(s):  
A. Deptula ◽  
T. Olczak ◽  
W. Lada ◽  
K. C. Goretta ◽  
A. Di Bartolomeo ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Nitric Acid ◽  
Thermal Treatment ◽  
Thermal Conversion ◽  
Temperature Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Temperature Treatment ◽  
Intermediate Phases ◽  
Superconducting Compounds

Thermal conversion of acetate-derived gels to YBa2Cu3Ox (Y–123), Bi2Sr2CaCu2Ox (Bi–2212), and (Bi, Pb)2Sr2Ca2Cu3Ox (Bi-2223) has been studied by thermal analysis, x-ray diffraction, and infrared spectroscopy. Carbonates formed above 200 °C during thermal treatment of all gels. Decomposition of the carbonates proved to be more difficult for Y-123 than for Bi-2212 or Bi-2223. However, all of the gels that were heated contained significant amounts of carbon after calcination. Complete decarbonization of materials was attained by treating the intermediate phases (e.g., those formed after calcination at 600 °C) with nitric acid and then subjecting them to a final thermal treatment. Removal of carbonates from the intermediate phases strongly accelerated formation of the superconducting compounds.

Study on Character of Ilmenite Modified by Thermal Treatment

2011 ◽  
Vol 284-286 ◽  
pp. 2090-2093 ◽  
Author(s):  
Xue Liang Xiong ◽  
Zhi Yang ◽  
Hong Yong Ouyang
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Oxidation Temperature ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray

The character of ilmenite was modified by pretreatment, the effect of pre-oxidation temperature and time on structure of ilmenite were investigated by X-ray diffraction(XRD) and Thermo-gravimetric/differential thermal analysis. The results indicated that new microcrystal rutile and FeTiO3·Fe2O3 solid solution were appeared on the surface of mineral below 800°C, but evident rutile crystals and pseudobrookite Fe2O3·TiO2 were appeared above 850°C with the structure of ilmenite disrupting simultaneously. The preoxidation time increased from 15min to 60min, evident microcrystal rutile and FeTiO3·Fe2O3 solid solution were appeared by degrees without structure of ilmenite breaking.

Effect of thermal treatment on lanthanide montmorillonites: dehydration

Clay Minerals ◽  
1980 ◽  
Vol 15 (4) ◽  
pp. 421-428 ◽  
Author(s):  
T. Mozas ◽  
S. Bruque ◽  
A. Rodriguez
Keyword(s):  
Thermal Analysis ◽  
Thermal Treatment ◽  
Interlayer Space ◽  
Lanthanide Ions ◽  
Water Molecules ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
X Ray ◽  
Water Layers

AbstractHydration/dehydration behaviour and the effect of various thermal treatments on montmorillonites saturated with lanthanide ions have been investigated by X-ray diffraction, thermal analysis (DTA, TG, DTG), IR spectroscopy and sorption-desorption of water vapour techniques. Heating at 150°C under 10−5 torr did not eliminate all the interlayer water of the montmorillonite, neither did it affect the CEC. Heating above 160°C caused a reduction in CEC. At 25°C La-montmorillonite takes up a maximum of three water layers in the interlayer space, the water molecules adopting a nonacoordinated distribution around the La3+ cation.

scholarly journals Thermal Annealing and Phase Transformation of Serpentine-Like Garnierite

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Micro Raman Spectroscopy

This study is focused on the vibrational and microstructural aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite were annealed in static air between room temperature and 1000 °C. The kinetic of the transformation was investigated by means of thermogravimetric and differential thermal analysis, and the final product was extensively characterized via micro-Raman spectroscopy and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

Phase Assembly of Ti2SnC Powders

2011 ◽  
Vol 412 ◽  
pp. 187-190 ◽  
Author(s):  
Chun Long Guan ◽  
Guo Qin Liu ◽  
Ying Chun Shan
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Intermetallic Compounds ◽  
Single Phase ◽  
Reaction Path ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermediate Phases ◽  
Reaction Equations ◽  
Phase Relationships

Ti2SnC powders (Ti: Sn: C =2: 1.2: 1, mol.%) were synthesized by pressureless sintering in argon in the temperature range of 600 to 1050°C using Ti, Sn and graphite powders as the initial materials. The phase relationships during reaction in the ternary system Ti-Sn-C have been investigated. The products for identification and analysis were characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). The reaction path for the formation of Ti2SnC can be described in the following steps. Sn melted at 230°C, which provided a favorable liquid circumstance for the reactions between Ti and Sn to form Ti-Sn intermetallic compounds. Results showed that Ti6Sn5 and Ti5Sn3 intermediate phases were formed in turn with increase of temperature. Up to 1050°C, with consumption of Ti5Sn3 phases completely, the amount of Ti2SnC increased significantly. Single phase Ti2SnC with small amount of TiC was produced. Combined with the results of differential thermal analysis (DTA) and X-ray diffraction (XRD), it is revealed that Ti2SnC phase is formed by the reaction of Ti–Sn intermetallic compounds, Ti and graphite. In addition, the reaction equations of the process from 230 to 1050°C were given.

scholarly journals Structural changes of Cr-beidellite treated up to 1350 °C in oxygen or nitrogen atmospheres

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 64-68
Author(s):  
H. S. Santos ◽  
A. M. Cesio ◽  
M. Gauna ◽  
V. F. Justo ◽  
C. Volzone
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Thermal Treatment ◽  
Structural Changes ◽  
Pillared Clay ◽  
Nitrogen Atmosphere ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineralogical Phases

Abstract Beidellite clay mineral after intercalation of OH-Cr(III) species were thermally analyzed up to 1350 °C in oxygen and nitrogen atmospheres. OH-Cr-beidellite can be used as a pillared clay precursor for catalysis or as adsorbent applications. However, in this paper beidellite enriched in chromium were analyzed at different thermal treatments up to high temperature for evaluating structural changes for possible future ceramic applications. The structural changes were followed by thermal analysis and X-ray diffraction. The thermal treatment of OH-Cr-beidellite in oxygen and nitrogen atmospheres developed different mineralogical phases up to 1050 °C, but at higher temperatures, the same phases were developed in both atmosphere treatments. Eskolaite phase (Cr2O3) appeared in the sample after heating at 400 °C in oxygen atmosphere, whereas grimaldite (CrO-OH) in nitrogen atmosphere, maintaining the starting phases. At 1000 °C the raw clay minerals disappeared, as it is knew. At 1050 °C in nitrogen atmosphere, grimaldite was absent and eskolaite appeared. At 1350 °C in the samples calcined in both atmospheres, quartz, cristobalite and mullite as the main phases and in lower contents aluminum oxide and aluminum-chromium oxide [(Al,Cr)2O3] were present.

scholarly journals Correlation between the green-like coloration and the structural and electronic properties of celadon glazes (I)

Cerâmica ◽  
2012 ◽  
Vol 58 (347) ◽  
pp. 328-337 ◽  
Author(s):  
M. Hidaka ◽  
K. Takeuchi ◽  
R. P. Wijesundera ◽  
L. S. R. Kumara ◽  
M. Watanabe ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Treatment ◽  
Fluorescence Analysis ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electronic Properties ◽  
X Ray Absorption ◽  
Fe Ions

Celadon glazes have been investigated by means of ordinary X-ray fluorescence analysis, and X-ray diffraction and X-ray absorption spectra using synchrotron radiation. The tentative glazes are prepared by mixing raw celadon materials of Masuda feldspar, limestone, quartz, and extra-added Fe2O3 of about 1wt% at thermal treatment till about 1300 °C. It is found that the glaze-colors strongly depend on the Fe2O3 amount and the high-temperature treatment under oxidizing and deoxidizing in the used kiln. Especially, the characteristic color of blue-green, white-green-brown, and white-blue-green result from complex hybridized 3d5L and 3d6L bands. The 3d6L hybridization is induced by an electronic exchange interaction between an empty 3d6 orbital of Fe ions and an occupied 2p orbital of surrounding O ions in the (SiO2 - Al2O3 - CaO) basic complex ceramics of glass-state under the deoxidizing thermal treatment.

Phase Formation Route of Cr2AlC Ceramics from Cr, Al and Graphite Powders

2010 ◽  
Vol 105-106 ◽  
pp. 192-194 ◽  
Author(s):  
Chun Long Guan ◽  
Guo Qin Liu ◽  
Ying Chun Shan
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Ternary System ◽  
Intermetallic Compounds ◽  
Single Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermediate Phases ◽  
Reaction Equations ◽  
Phase Relationships

Cr2AlC ceramics (Cr:Al:C =1:1.2:1 mol.%) were synthesized by powder metallurgical method in argon in the temperature range of 700 to1250°C using Cr, Al and graphite powders as the initial materials. The phase relationships during reaction in the ternary system Cr-Al-C were investigated. The products were characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). It was found that Cr9Al17, Al8Cr5 and Cr2Al intermediate phases were formed in turn with increase of temperature. Up to 1050°C, with consumption of Cr9Al17 and Al8Cr5 phases completely, the amount of Cr2Al increased significantly. Single phase Cr2AlC with small amount of Cr7C3 was produced until 1250°C. Combined with the results of differential thermal analysis (DTA) and X-ray diffraction (XRD), it is revealed that Cr2AlC phase is formed by the reaction of Cr–Al intermetallic compounds, Cr, Al and graphite. In addition, the reaction equations of the process from 660 to1250°C were given.

GRAFTING INTERLAYER MoO42- IN Mg/Al LAYERED DOUBLE HYDROXIDE BY THERMAL TREATMENT BELOW COLLAPSING THE LAYERED STRUCTURE

2012 ◽  
Vol 06 ◽  
pp. 127-132
Author(s):  
Kennichi Muranishi ◽  
Akihiro Shimamura ◽  
Masashi Kurashina ◽  
Eiji Kanezaki
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Layered Double Hydroxide ◽  
Interlayer Spacing ◽  
Basal Spacing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interlayer Anion ◽  
Double Hydroxide

Some kinds of Mg / Al layered double hydroxide (LDH) with oxometalate have been prepared by mean of anion exchange. Products were characterized by powder X-ray diffraction (XRD), chemical analysis and Thermogravimetry - Differential Thermal Analysis (TG-DTA). Results showed that the basal spacing of heated LDH decreased with heating to 300 °C. This revealed the decrease of interlayer spacing and the interlayer anion being grafted to the layer of LDH because the decreased interlayer spacing of the heated LDH was smaller than the size of the interlayer anion.

scholarly journals Effect of Deposition Conditions on Oxide Parameters of Silicon

2021 ◽  
Vol 229 ◽  
pp. 01046
Author(s):  
Souad Merabet ◽  
Ahlem Alioua
Keyword(s):  
Diffusion Coefficient ◽  
Thermal Treatment ◽  
Thermal Oxidation ◽  
Parabolic Rate Constant ◽  
Oxide Thickness ◽  
Temperature Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Films ◽  
Deposition Conditions

In this study, the effect of deposition conditions and the temperature thermal treatment on the oxide parameters of two structures of silicon layers were investigated. The study present the evolution of boron profiles following a dry thermal oxidation in poly-Si/SiO2/c-Si films deposited at 520°C and 605°C temperatures and thermally oxidized in dry oxygen at respectively temperature 840°C, 945°C and 1050°C for tr=1h33’duration. The results show that the deposition conditions and the temperature treatment make a very important impact on the obtained films, which affect the redistribution and localization of dopants. It has been observed that the obtained value of the linear and the parabolic rate constant, the diffusion coefficient and the oxidation thickness are higher in the films deposited at Td = 520°C than those deposited at Td = 605°C. Also, the X-ray diffraction is strongly affected by the oxide thickness deposited between poly-silicon layers and crystalline substrates.

scholarly journals Effect of Deposition Conditions on Oxide Parameters of Silicon

2021 ◽  
Vol 229 ◽  
pp. 01037
Author(s):  
Souad Merabet ◽  
Ahlem Alioua ◽  
Bilal Djellil
Keyword(s):  
Diffusion Coefficient ◽  
Thermal Treatment ◽  
Parabolic Rate Constant ◽  
Oxide Thickness ◽  
Temperature Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Films ◽  
Deposition Conditions

In this study, the effect of deposition conditions and the temperature thermal treatment on the oxide parameters of two structures of silicon layers were investigated. The study present the evolution of in situ boron profiles following a dry thermal oxidation in poly-Si/SiO2/c-Si films deposited at 520°C and 605°C temperatures and thermally oxidized in dry oxygen at respectively temperature 840°C, 945°C and 1050°C for duration tr=1h33’. The results show that the deposition conditions and the temperature treatment make a very important impact on the obtained films, which affect the redistribution and localization of dopants. It has been observed that the obtained value of the linear and the parabolic rate constant, the diffusion coefficient and the oxidation thickness are higher in the films deposited at Td = 520°C than those deposited at Td = 605°C. Also, the X-ray diffraction is strongly affected by the oxide thickness deposited between poly-silicon layers and crystalline substrates.

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