Synthesis Mechanisms of the Combustion Synthesis of IntermetCers Composites

2006 ◽  
Vol 45 ◽  
pp. 1029-1034 ◽  
Author(s):  
C. Curfs ◽  
A.E. Terry ◽  
G.B.M. Vaughan ◽  
Erich H. Kisi ◽  
M.A. Rodriguez ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Nickel Aluminide ◽  
The Self ◽  
Scanning Electron Micrographs ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Combustion Modes ◽  
Intermediate Phases ◽  
Diffraction Patterns

Combustion synthesis techniques have been applied to an equiatomic mixture of Aluminium, Nickel, Titanium and Carbon powders in order to obtain NiAl/TiC composites. Both combustion modes have been used: the Self-propagating High-temperature mode (SHS), in which the reaction propagates through the sample under the form of a heat wave and the Thermal Explosion mode (TES), in which the reaction occurs simultaneously in the complete sample. The reactions have been followed in-situ by time-resolved diffraction, using synchrotron X-rays for the SHS mode and neutrons for the TES mode. Scanning Electron Micrographs and X-ray diffraction patterns of the final product have shown that the same final products were obtained when the mixture was synthesised under both combustion modes: a composite made of small and round TiC particles (~1 micron) embedded into a matrix of larger NiAl grains (5 microns). However, the Time-Resolved Diffraction studies have shown that, even with the same final products, the two combustion modes follow two completely different routes. Thus, for the SHS mode, the reaction is triggered by the formation of Nickel Aluminide and 3 intermediate phases are observed, and for the TES mode, the self-sustained reaction starts with the formation of Titanium Carbide and no intermediate phases have been seen.

scholarly journals Time-resolved X-ray diffraction at NERL

2001 ◽  
Vol 19 (1) ◽  
pp. 125-131 ◽  
Author(s):  
KENICHI KINOSHITA ◽  
HIDEKI HARANO ◽  
KOJI YOSHII ◽  
TAKERU OHKUBO ◽  
ATSUSHI FUKASAWA ◽  
...  
Keyword(s):  
Research Laboratory ◽  
Experimental Results ◽  
X Rays ◽  
Nuclear Engineering ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Engineering Research ◽  
Fs Laser ◽  
Diffraction Patterns

For ultrafast material analyses, we constructed the time-resolved X-ray diffraction system utilizing ultrashort X-rays from laser-produced plasma generated by the 12-TW–50-fs laser at the Nuclear Engineering Research Laboratory. Ultrafast transient changes in laser-irradiated GaAs crystals were observed as X-ray diffraction patterns. Experimental results were compared with numerical analyses.

scholarly journals Picosecond time-resolved X-ray diffraction from laser-shocked semiconductors

2004 ◽  
Vol 22 (3) ◽  
pp. 285-288 ◽  
Author(s):  
KAZUTAKA G. NAKAMURA ◽  
YOICHIRO HIRONAKA ◽  
HIDETAKA KAWANO ◽  
HIROAKI KISHIMURA ◽  
KEN-ICHI KONDO
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Structural Dynamics ◽  
Lattice Deformation ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Femtosecond Laser Beam ◽  
Diffraction Patterns

Ultrashort pulsed hard X rays are generated by focusing an intense femtosecond laser beam onto metal targets. Kαemissions are obtained from a Cu target. Picosecond time-resolved X-ray diffraction is performed to investigate structural dynamics of laser-shocked semiconductors using the laser plasma X-ray pulses. Lattice deformation associated with shock-wave propagation is directly observed. Evolution of strain profiles inside the crystal is determined without disturbance from the time-resolved X-ray diffraction patterns.

scholarly journals Direct mapping of fiber diffraction patterns into reciprocal space

2009 ◽  
Vol 42 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Norbert Stribeck ◽  
Ulrich Nöchel
Keyword(s):  
Direct Method ◽  
Reciprocal Space ◽  
Polymer Materials ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Direct Mapping ◽  
Fiber Diffraction ◽  
Mapping Parameters ◽  
Diffraction Patterns ◽  
A Direct Method

On the basis of the concept of Polanyi [Z. Phys.(1921),7, 149–180], the mapping of fiber diffraction patterns into reciprocal space is revisited. The result is a set of concise mapping relations that does not contain any approximations. This set permits the design of a direct method that, in principle, does not require refinement of mapping parameters even for patterns of tilted fibers. The method is unsuitable for diffuse scattering patterns. If inaccuracies of two pixels can be tolerated, a pattern is automatically mapped into reciprocal space in real time. The method is proposed for the processing of the extensive sets of patterns that are recorded in time-resolved wide-angle X-ray diffraction investigations of polymer materials.

scholarly journals CrisDi School: disseminating crystallography in Piedmont, Italy

2014 ◽  
Vol 70 (a1) ◽  
pp. C1277-C1277
Author(s):  
Domenica Marabello ◽  
Angelo Agostino ◽  
Piera Benna ◽  
Giovanna Dinardo ◽  
Carlo Lamberti ◽  
...  
Keyword(s):  
Large Scale ◽  
Kinetic Studies ◽  
Research Centre ◽  
Main Task ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
New Methodologies ◽  
The University ◽  
Basic Level

The Interdepartmental Research Centre for the Development of Crystallography (CrisDi) aims to be an institution of reference for researchers at the University of Turin interested on the field of diffraction (X-rays, neutrons and electrons), to promote the knowledge and dissemination of crystallography, and to facilitate the access to available laboratory instrumentation (diffractometers and TEM) and to large scale facilities (synchrotron and neutron sources). CrisDi hosts scientists with interest in the fields of solid state chemistry and physics, organic, inorganic, organometallic and theoretical chemistry, mineralogy, biology, pharmaceutical and agricultural sciences. The Centre encourages the design and the development of new methodologies and applications, and supports the enhancement of the available instruments. The submission of proposals at large scale instruments is encouraged specially for young researchers and PhD students. The cultural and scientific interchange among crystallographers coming from different disciplines is strongly encouraged by CrisDi. A main task of the CrisDi is the annual organization of a post-grade level School with a series of courses dedicated to: (i) basic level crystallography (symmetry, theory of diffraction, crystal-chemistry), diffraction techniques (single crystal and powder X-ray diffraction, neutron and electron scattering); (ii) advanced level (high temperature and high pressure structural studies, macromolecular crystallography, time resolved crystallography and kinetic studies); (iii) spectroscopic approaches (XAFS, XANES, XES and NMR) in crystallography. The school, which is held every year in May for about 20 ECTS equivalent, has no tuition fees and is also open to non-academia people.

X-Ray Diffraction

2021 ◽  
pp. 408-480
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Point Group ◽  
Polycrystalline Materials ◽  
X Rays ◽  
X Ray Diffraction ◽  
Symmetry Point Group ◽  
X Ray ◽  
Atomic Scattering ◽  
Scattering Factor ◽  
Diffraction Patterns ◽  
Lattice Planes

X-rays diffraction is fundamental to understanding the structure and crystallography of biological, geological, or technological materials. X-rays scatter predominantly by the electrons in solids, and have an elastic (coherent, Thompson) and an inelastic (incoherent, Compton) component. The atomic scattering factor is largest (= Z) for forward scattering, and decreases with increasing scattering angle and decreasing wavelength. The amplitude of the diffracted wave is the structure factor, F hkl, and its square gives the intensity. In practice, intensities are modified by temperature (Debye-Waller), absorption, Lorentz-polarization, and the multiplicity of the lattice planes involved in diffraction. Diffraction patterns reflect the symmetry (point group) of the crystal; however, they are centrosymmetric (Friedel law) even if the crystal is not. Systematic absences of reflections in diffraction result from glide planes and screw axes. In polycrystalline materials, the diffracted beam is affected by the lattice strain or grain size (Scherrer equation). Diffraction conditions (Bragg Law) for a given lattice spacing can be satisfied by varying θ or λ — for study of single crystals θ is fixed and λ is varied (Laue), or λ is fixed and θ varied to study powders (Debye-Scherrer), polycrystalline materials (diffractometry), and thin films (reflectivity). X-ray diffraction is widely applied.

The Use of 2-D Detector Utilizing Laser-Stimulated Luminescence for X-ray Diffraction Studies on Mechanical Behaviour of Materials

1989 ◽  
Vol 33 ◽  
pp. 389-396 ◽  
Author(s):  
Y. Yoshioka ◽  
T. Shinkai ◽  
S. Ohya
Keyword(s):  
Fracture Analysis ◽  
X Rays ◽  
Large Reduction ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Material Evaluation ◽  
Position Sensitive ◽  
Diffraction Patterns ◽  
Position Sensitive Detectors

The development of linear position-sensitive detectors (PSD) has resulted in a large reduction of data acquisition times in the field of x-ray stress analysis. However, we also require two-dimensional (2-D) diffraction patterns for material evaluation. Especially, the microbeam x-ray diffraction technique gives valuable information on the structure of crystalline materials and this technique has been applied to fracture analysis by x-rays. Many kinds of 2-D PSD have been developed that have insufficient spatial resolution. So x-ray film has still been used as a 2-D detector, but it requires relatively long exposure times and then the process after exposure is very troublesome.

scholarly journals A Flow-Through Reaction Cell for Studying Minerals Leaching by In-Situ Synchrotron Powder X-ray Diffraction

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 990
Author(s):  
Fatemeh Nikkhou ◽  
Fang Xia ◽  
Xizhi Yao ◽  
Idowu A. Adegoke ◽  
Qinfen Gu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Pressure Leaching ◽  
X Ray Diffraction ◽  
Reaction Cell ◽  
Time Resolved ◽  
X Ray ◽  
Ore Minerals ◽  
Flow Through ◽  
Diffraction Patterns

A flow-through reaction cell has been developed for studying minerals leaching by in-situ time-resolved powder X-ray diffraction, allowing for a better understanding of the leaching mechanisms and kinetics. The cell has the capability of independent control of temperature (up to 95 °C) and flow rate (>0.5 mL min−1) for atmospheric pressure leaching. It was successfully tested at the powder diffraction beamline at the Australian Synchrotron. Galena powder was leached in a citrate solution under flow-through condition at a flow rate of 0.5 mL min−1, while diffraction patterns were collected during the entire leaching process, showing rapid galena dissolution without the formation of secondary mineral phases. The flow-through cell can be used to study leaching processes of other ore minerals.

Electrochemical Deposition and Characterization of Cd-Fe-Se Thin Films

2009 ◽  
Vol 68 ◽  
pp. 69-76 ◽  
Author(s):  
S. Thanikaikarasan ◽  
T. Mahalingam ◽  
K. Sundaram ◽  
Tae Kyu Kim ◽  
Yong Deak Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Hexagonal Structure ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Selenide ◽  
Glass Substrates ◽  
Diffraction Patterns ◽  
Cadmium Iron Selenide ◽  
Deposited Films

Cadmium iron selenide (Cd-Fe-Se) thin films were deposited onto tin oxide (SnO2) coated conducting glass substrates from an aqueous electrolytic bath containing CdSO4, FeSO4 and SeO2 by potentiostatic electrodeposition. The deposition potentials of Cadmium (Cd), Iron (Fe), Selenium (Se) and Cadmium-Iron-Selenide (Cd-Fe-Se) were determined from linear cathodic polarization curves. The deposited films were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by x-rays (EDX) and optical absorption techniques, respectively. X-ray diffraction patterns shows that the deposited films are found to be hexagonal structure with preferential orientation along (100) plane. The effect of FeSO4 concentration on structural, morphological, compositional and optical properties of the films are studied and discussed in detail.

Combustion synthesis of AlN with melamine as an additive

2006 ◽  
Vol 21 (3) ◽  
pp. 747-753 ◽  
Author(s):  
Gunchoo Shim ◽  
Je-Shin Park ◽  
Sung-Wook Cho
Keyword(s):  
Aluminum Nitride ◽  
Combustion Synthesis ◽  
Reaction Rates ◽  
Nitrogen Pressure ◽  
Chamber Pressure ◽  
Nitrogen Flow ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
Diffraction Patterns ◽  
Nitrogen Contents

Melamine (C3H6N6) was used as an additive for synthesizing aluminum nitride by combustion synthesis. It was found that at least 0.1 M of melamine addition to 1 M of aluminum and 0.8 MPa of nitrogen pressure were necessary to initiate a stable reaction. In addition to melamine, however, use of aluminum nitride as a diluent and application of forced nitrogen flow yielded better results. Analyzing the reaction temperatures, reaction rates, nitrogen contents, x-ray diffraction patterns, and scanning electron microscopy photographs, the optimum conditions for synthesizing AlN were established: (i) reactants were 90 wt% (1 M Al + 0.1 M melamine) + 10 wt% AlN diluent, (ii) chamber pressure was 0.9 MPa, and (iii) nitrogen flow rate was 15 l/min. Under these conditions, aluminum nitride with the stoichiometric nitrogen content of 34 wt% could be obtained.

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