The effect of iron content on dehydration kinetics of talc

2020 ◽  
Author(s):  
Li Yi ◽  
Ruixin Zhang ◽  
Siyu Yang
Keyword(s):  
Subduction Zone ◽  
Iron Content ◽  
Diffraction Experiment ◽  
Dehydration Reaction ◽  
X Ray Diffraction ◽  
Hydrous Mineral ◽  
Hydrous Minerals ◽  
X Ray ◽  
Kinetics Of

<p>    Subduction zone is a distinct activity structure of hypocenter distribution of earthquakes. Hydrous minerals are involved in the chemical and physical activities in subduction zones. As a widely distributed hydrous mineral in shallow depths, talc has potential significance in various fault activities, and its dehydration reaction may be an important cause of the earthquake. Iron is a main element of the earth's crust, and the iron contents of hydrous minerals have a large impact on melting point, the rheological strength physical and chemical properties of the rocks. As a common hydrous mineral, the iron content of talc is not uniform; therefore, it is very important to study the dehydration kinetics of talc with different iron content.</p><p>    The dehydration reaction of three different iron contents talc was studied by means of synchronous thermal analysis, high temperature and high pressure differential thermal experiment and in-situ synchrotron X-ray diffraction experiment. Data of synchronous thermal analysis was calculated by Flynn-Wall-Ozawa (FWO). The activation energies of different iron content talc were calculated as 359.8 kJ/mol（FeO：0.4wt%），368.2.0 kJ/mol（FeO：2.0wt％），belonging to the second-order reaction. Data of in-situ synchrotron X-ray diffraction experiment was fitted by Avrami equation, E=350 kJ/mol（FeO：2.0wt％），n=1.67. The dehydration of talc followed random nucleation and growth mechanism. High content of iron obviously resulted in lower dehydration temperature.</p><p>  The release rate of talc dehydration fluid was 2.3E-05 to 6.1E-06 obtained by in-situ synchrotron X-ray diffraction experiment，it could lead to local overpressure induced rock brittle fracture. The supercritical fluid produced by the dehydration of talc in the subduction zone further attenuates the rock, resulting in local overpressure, which eventually leads to rock failure. The results suggested that the dehydration of different iron contents of talc may occur at the different depth around hundreds of kilometers, so the study was significant to our understanding of the genetic mechanism of earthquakes in the subduction zone.</p>

scholarly journals In situ monitoring of hydrothermal reactions by X-ray diffraction with Bragg–Brentano geometry

2020 ◽  
Vol 53 (4) ◽  
pp. 1163-1166
Author(s):  
Karsten Mesecke ◽  
Winfried Malorny ◽  
Laurence N. Warr
Keyword(s):  
Quantitative Information ◽  
In Situ Monitoring ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Saturated Vapour Pressure ◽  
Concrete Production ◽  
Aerated Concrete ◽  
Kinetics Of

This note describes an autoclave chamber developed and constructed by Anton Paar and its application for in situ experiments under hydrothermal conditions. Reactions of crystalline phases can be studied by successive in situ measurements on a conventional laboratory X-ray diffractometer with Bragg–Brentano geometry at temperatures <483 K and saturated vapour pressure <2 MPa. Variations in the intensity of X-ray diffraction reflections of both reactants and products provide quantitative information for studying the reaction kinetics of both dissolution and crystal growth. Feasibility is demonstrated by studying a cementitious mixture used for autoclaved aerated concrete production. During a period of 5.7 h at 466 K and 1.35 MPa, the crystallization of torbermorite and the partial consumption of quartz were monitored.

Kinetics of Multi-Step Redox Processes by Time-Resolved In Situ X-ray Diffraction

2016 ◽  
Vol 88 (11) ◽  
pp. 1684-1692 ◽  
Author(s):  
Lukas C. Buelens ◽  
Vladimir V. Galvita ◽  
Hilde Poelman ◽  
Christophe Detavernier ◽  
Guy B. Marin
Keyword(s):  
Redox Processes ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of

In situ high temperature X-ray diffraction study of the kinetics of phase separation in the uranium-plutonium mixed oxide (U0.55Pu0.45)O2-x

2014 ◽  
Vol 1645 ◽  
Author(s):  
Romain VAUCHY ◽  
Renaud.C. BELIN ◽  
Anne-Charlotte ROBISSON ◽  
Fiqiri HODAJ
Keyword(s):  
Phase Separation ◽  
Room Temperature ◽  
Mixed Oxides ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
Fundamental Interest ◽  
X Ray ◽  
Uranium Plutonium ◽  
Kinetics Of

ABSTRACTUranium-plutonium mixed oxides incorporating high amounts of plutonium are considered for future nuclear reactors. For plutonium content higher than 20%, a phase separation occurs, depending on the temperature and on the oxygen stoichiometry. This phase separation phenomenon is still not precisely described, especially at high plutonium content. Here, using an original in situ fast X-ray diffraction device dedicated to radioactive materials, we evidenced a phase separation occurring during rapid cooling from 1773 K to room temperature at the rate of 0.05 and 2 K per second for a (U0.55Pu0.45)O2-x compound under a reducing atmosphere. The results show that the cooling rate does not impact the lattice parameters of the obtained phases at room temperature but their fraction. In addition to their obvious fundamental interest, these results are of utmost importance in the prospect of using uranium-plutonium mixed oxides with high plutonium content as nuclear fuels.

Grain-Growth Kinetics of Nanocrystalline Iron Studied In Situ by Synchrotron Real-Time X-ray Diffraction

2000 ◽  
Vol 104 (11) ◽  
pp. 2467-2476 ◽  
Author(s):  
H. Natter ◽  
M. Schmelzer ◽  
M.-S Löffler ◽  
C. E. Krill ◽  
A. Fitch ◽  
...  
Keyword(s):  
Real Time ◽  
Grain Growth ◽  
Growth Kinetics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanocrystalline Iron ◽  
Grain Growth Kinetics ◽  
Kinetics Of

A Model for Formation and Consumption of Transient Phase

2011 ◽  
Vol 172-174 ◽  
pp. 646-651 ◽  
Author(s):  
Gamra Tellouche ◽  
Khalid Hoummada ◽  
Dominique Mangelinck ◽  
Ivan Blum
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Formation ◽  
Transient Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Proposed Model ◽  
Transient Phases ◽  
Kinetics Of

The phase formation sequence of Ni silicide for different thicknesses is studied by in situ X ray diffraction and differential scanning calorimetry measurements. The formation of a transient phase is observed during the formation of δ-Ni2Si; transient phases grow and disappear during the growth of another phase. A possible mechanism is proposed for the transient phase formation and consumption. It is applied to the growth and consumption of θ-Ni2Si. A good accordance is found between the proposed model and in situ measurement of the kinetics of phase formation obtained by x-ray diffraction and differential scanning calorimetry for higher thickness.

IN SITU STUDIES OF EPITAXIAL GROWTH BY SYNCHROTRON X-RAY DIFFRACTION

2006 ◽  
Vol 13 (02n03) ◽  
pp. 155-166 ◽  
Author(s):  
WOLFGANG BRAUN ◽  
KLAUS H. PLOOG
Keyword(s):  
Ostwald Ripening ◽  
Crystal Surface ◽  
High Energy ◽  
Molecular Beam Epitaxy Growth ◽  
X Rays ◽  
Surface Kinetics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetics Of

X-rays are ideal to study the structure of crystals due to their weak interaction with matter and in most cases allow a quantitative analysis using kinematical theory. To study the incorporation of atoms during crystal growth and to analyze the kinetics on the crystal surface high primary beam intensities available at synchrotrons are required. Our studies of the molecular beam epitaxy growth of III–V semiconductors reveal that, despite their similarity in crystal structure, the surface kinetics of GaAs (001), InAs (001) and GaSb (001) differ strongly. GaAs shows an unexpectedly large coarsening exponent outside the predicted range of Ostwald ripening models during recovery. GaSb exhibits dramatically different surface morphology variations during growth and recovery. Overgrowth of GaAs by epitaxial MnAs demonstrates the ability of X-ray diffraction to follow an interface as it is buried during heteroepitaxy, which is not possible by reflection high-energy electron diffraction.

Recrystallization of AA1050 Studied by 3DXRD

2006 ◽  
Vol 519-521 ◽  
pp. 1569-1578
Author(s):  
Dorte Juul Jensen
Keyword(s):  
Single Crystals ◽  
High Energy ◽  
Nucleation And Growth ◽  
X Rays ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
3 Dimensional ◽  
Kinetics Of

By 3 dimensional X-ray diffraction (3DXRD) using high energy X-rays from synchrotron sources it is possible to study in-situ the nucleation and growth during recrystallization. In this paper it is described and discussed how 3DXRD can supplement EBSP measurements of nucleation and growth. Three types of studies are considered: i) orientation relationships between nuclei and parent deformed matrix, ii) recrystallization kinetics of individual bulk grains and iii) filming of growing grains in deformed single crystals.

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