Development of an in situ X-ray diffraction system for hydrothermal reactions and its application to autoclaved aerated concrete formation

2011 ◽  
Vol 26 (2) ◽  
pp. 126-128 ◽  
Author(s):  
J. Kikuma ◽  
M. Tsunashima ◽  
T. Ishikawa ◽  
S. Matsuno ◽  
A. Ogawa ◽  
...  

An in situ time-resolved XRD system for hydrothermal reaction has been developed in order to investigate the phase evolution during autoclave process in autoclaved aerated concrete (AAC) formation. The system includes a novel autoclave cell for transmission XRD with thin beryllium windows, a two-dimensional photon-counting pixel array detector, and uses high energy X-rays from a synchrotron radiation source. The temperature and pressure inside the cell are extremely stable during hydrothermal reaction over the course of several hours. The system was utilized for the formation reaction of AAC. Phase evolution was clearly observed, including several intermediate phases, and detailed information on the structural changes during the hydrothermal reaction were obtained.

2011 ◽  
Vol 26 (2) ◽  
pp. 134-137 ◽  
Author(s):  
K. Matsui ◽  
A. Ogawa ◽  
J. Kikuma ◽  
M. Tsunashima ◽  
T. Ishikawa ◽  
...  

Hydrothermal formation reaction of tobermorite in the autoclaved aerated concrete (AAC) process has been investigated by in situ X-ray diffraction. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. XRD measurements were conducted in a temperature range 100–190°C throughout 12 h of reaction time with a time interval of 4.25 min under a saturated steam pressure. To clarify the tobermorite formation mechanism in the AAC process, the effect of Al addition on the tobermorite formation reaction was studied. As intermediate phases, non-crystalline calcium silicate hydrate (C-S-H), hydroxylellestadite (HE), and katoite (KA) were clearly observed. Consequently, it was confirmed that there were two reaction pathways via C-S-H and KA in the tobermorite formation reaction of Al containing system. In addition, detailed information on the structural changes during the hydrothermal reaction was obtained.


2010 ◽  
Vol 25 (2) ◽  
pp. 210-210
Author(s):  
J. Kikuma ◽  
M. Tsunashima ◽  
T. Ishikawa ◽  
S. Matsuno ◽  
K. Matsui ◽  
...  

1998 ◽  
Vol 524 ◽  
Author(s):  
D. D. Dominguez ◽  
P. L. Hagans ◽  
E. F. Skelton ◽  
S. B. Qadri ◽  
D. J. Nagel

ABSTRACTWith low energy x-rays, such as those from a Cu x-ray tube, only the outer few microns of a metallic sample can be probed. This low penetrating power prohibits structural studies from being carried out on the interior of an electrode in an electrochemical cell because of absorption by the cell material, electrodes and the electrolyte. The work described in this paper circumvents this problem by utilizing high energy, high brightness x-rays produced on the superconducting wiggler beam line, X-17C, at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The penetrating power of the higher energy x-rays allowed Pd diffraction spectra to be obtained in-situ on a 1 mm diameter Pd wire cathode during electrolysis of heavy water. Moreover, the beam (28 × 28 μm in cross-section) allowed diffraction spectra to be acquired as a function of distance across the sample. Spectra were recorded in 50 μm steps from the edge of the Pd wire to its core. This was done at 2 minute intervals as a function of electrolysis time. The α-β phase transition induced in the Pd while deuterium was electrochemically absorbed was observed by monitoring the Pd-(422) diffraction peaks. Results allowed the diffusion rate and the diffusivity of deuterium atoms in the Pd wire to be determined. Other features of the structural changes associated with the absorption of deuterium into Pd are reported.


2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
David Pennicard ◽  
Heinz Graafsma ◽  
Michael Lohmann

The new synchrotron light source PETRA-III produced its first beam last year. The extremely high brilliance of PETRA-III and the large energy range of many of its beamlines make it useful for a wide range of experiments, particularly in materials science. The detectors at PETRA-III will need to meet several requirements, such as operation across a wide dynamic range, high-speed readout and good quantum efficiency even at high photon energies. PETRA-III beamlines with lower photon energies will typically be equipped with photon-counting silicon detectors for two-dimensional detection and silicon drift detectors for spectroscopy and higher-energy beamlines will use scintillators coupled to cameras or photomultiplier tubes. Longer-term developments include ‘high-Z’ semiconductors for detecting high-energy X-rays, photon-counting readout chips with smaller pixels and higher frame rates and pixellated avalanche photodiodes for time-resolved experiments.


ce/papers ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 253-258
Author(s):  
Furkan Gokmen ◽  
Baris Binici ◽  
Erdem Canbay ◽  
Alper Aldemir ◽  
Mustafa Kagan Ogdu ◽  
...  

2018 ◽  
Vol 25 (6) ◽  
pp. 1627-1633 ◽  
Author(s):  
Koji Ohara ◽  
Satoshi Tominaka ◽  
Hiroki Yamada ◽  
Masakuni Takahashi ◽  
Hiroshi Yamaguchi ◽  
...  

A dedicated apparatus has been developed for studying structural changes in amorphous and disordered crystalline materials substantially in real time. The apparatus, which can be set up on beamlines BL04B2 and BL08W at SPring-8, mainly consists of a large two-dimensional flat-panel detector and high-energy X-rays, enabling total scattering measurements to be carried out for time-resolved pair distribution function (PDF) analysis in the temperature range from room temperature to 873 K at pressures of up to 20 bar. For successful time-resolved analysis, a newly developed program was used that can monitor and process two-dimensional image data simultaneously with the data collection. The use of time-resolved hardware and software is of great importance for obtaining a detailed understanding of the structural changes in disordered materials, as exemplified by the results of commissioned measurements carried out on both beamlines. Benchmark results obtained using amorphous silica and demonstration results for the observation of sulfide glass crystallization upon annealing are introduced.


2020 ◽  
Vol 91 (9) ◽  
pp. 093901
Author(s):  
C. Gombola ◽  
G. Hasemann ◽  
A. Kauffmann ◽  
I. Sprenger ◽  
S. Laube ◽  
...  

2016 ◽  
Vol 714 ◽  
pp. 116-121 ◽  
Author(s):  
Ester Helanova ◽  
Rostislav Drochytka ◽  
Vit Cerný

The quality of the aerated concrete strongly depends on the chemical composition of the raw materials, as well as the process of the hydrothermal reaction during autoclaving. Due to the variable chemical composition of fly ashes, it is necessary to identify the effect of each ion on the formation of the microstructure of aerated concrete. This paper examines the process of formation of tobermorite with the addition of sulphates in various percentage representation. The microstructure of aerated concrete is assessed using SEM images and the mineralogical by means of X-ray analysis.


2006 ◽  
Vol 13 (02n03) ◽  
pp. 155-166 ◽  
Author(s):  
WOLFGANG BRAUN ◽  
KLAUS H. PLOOG

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.


2006 ◽  
Vol 519-521 ◽  
pp. 1569-1578
Author(s):  
Dorte Juul Jensen

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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