A flame-heated gas-flow furnace for single-crystal X-ray diffraction

1992 ◽  
Vol 25 (5) ◽  
pp. 545-548 ◽  
Author(s):  
R. C. Peterson
Keyword(s):  
High Temperature ◽  
Gas Flow ◽  
Flow Regulation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Capability ◽  
Computer Controlled ◽  
Controlled Flow ◽  
The Stability ◽  
Flow Devices

A furnace using an inert-gas stream heated by an acetylene torch has been designed to conduct high temperature X-ray diffraction experiments. The design makes use of the stability of electrically heated gas-flow devices and the high-temperature capability of flame heaters. The gas flow is coaxial with the crystal mounting fibre resulting in a thermally stable environment controlled by the composition of the heated gas stream. Temperatures from 373 up to 1573 K are maintained by computer-controlled flow regulation of the acetylene flame based on the signal from a thermocouple on which the crystal is mounted. The results of a high-temperature X-ray diffraction study of Mg0.54Fe2+ 0.46Fe2O4, spinel are given as an example of the application of this furnace.

Computer-controlled high-temperature single-crystal X-ray diffraction experiments and temperature calibration

2008 ◽  
Vol 42 (1) ◽  
pp. 140-142 ◽  
Author(s):  
Hannes Krüger ◽  
Ludger Breil
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Open Source Software ◽  
Gas Flow ◽  
X Ray Diffraction ◽  
New Developments ◽  
X Ray ◽  
Computer Controlled ◽  
Interactive Data ◽  
Data Collections

This work provides a simple way to operate and calibrate single-crystal gas flow heaters that use heating currents up to 10 A. Devices used for this task are an I-7019R data acquisition interface (ICP DAS Co. Ltd, Hsinchu, Taiwan) and an SDP-2210 power unit (Manson Engineering Industrial Ltd, Hong Kong;Imax= 10 A,Vmax= 20 V), which are both connected to one computer. The presented open source softwarehtcontrol(http://htcontrol.sourceforge.net) is able to control the heating current and to monitor the temperature, which allows automated calibrations. In particular, this work targets Stoe IPDS II diffractometer systems with a Heatstream high-temperature (HT) device. The extra hard- and software enables computer-controlled HT data collection series, which are performed utilizing theWinXposesoftware (Stoe & Cie GmbH, Darmstadt, Germany). New developments inWinXposeallow non-interactive data collections, which are controlled by means of an XML file specifying the measurement conditions.

500℃ high-temperature reliability of Ni/Nb Ohmic contact on n-type 4H-SiC

2021 ◽  
Author(s):  
Vuong Van Cuong ◽  
Tadashi Sato ◽  
Takamichi Miyazaki ◽  
Tetsuya Meguro ◽  
Seiji Ishikawa ◽  
...  
Keyword(s):  
High Temperature ◽  
Ohmic Contact ◽  
Chemical Compounds ◽  
Etching Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ohmic Behavior ◽  
Transmission Electron ◽  
Current Voltage ◽  
The Stability

Abstract The reliability of Ni/Nb ohmic contact on n-type 4H-SiC at 500℃ was investigated. The current-voltage characteristics showed that, while the Ni(50)/Nb(50)/4H-SiC sample without applying the CF4:O2 etching process degraded just after 25-hour and lost ohmic behavior after 50-hour aging, the Ni(75)/Nb(25)/4H-SiC contact undergone CF4:O2 surface treatment still showed excellent stability after aging for 100 hours at 500℃. Though X-ray diffraction results indicated that the chemical compounds remained stable during the aging process, transmission electron microscopy showed that there was a redistribution of the chemical compounds at the interface of the contact after 500℃ aging. The depth distribution of the elements and energy dispersive X-ray analyses revealed that the contribution of carbon agglomeration at the interface accounted for the degradation of the sample without applying the etching process. Whereas the well-controlled excess carbon atoms of the contact undergone CF4:O2 treatment ensured the stability of this contact when operating at high-temperature ambient.

In-situ analysis of chemical expansion and stability of SOFC cathodes

2014 ◽  
Vol 1655 ◽  
Author(s):  
Mirela Dragan ◽  
Scott Misture
Keyword(s):  
High Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Lattice Parameter ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
Chemical Expansion ◽  
X Ray ◽  
Reducing Conditions ◽  
The Stability

ABSTRACTIn this work high-temperature X-ray diffraction has been used to investigate thermal and chemical expansion as well as overall phase stability for various cathode materials: Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF), La0.3Sr0.7CoO3 (LSC37), La0.6Sr0.4CoO3 (LSC64) and La0.6Sr0.4Fe0.8Co0.2O3 (LSCF), as a function of temperature in reducing conditions. When perovskites materials are under a low oxygen partial-pressure condition, the lattice parameter and overall dimension increase. Their chemical expansion has comparable values. From the viewpoint of the stability of these phases, the high-temperature X-ray diffraction results indicate no phase decomposition can be one of the reasons for material failure at the current experimental oxygen partial pressure. LSF is most stable, while LSC and LSCF form oxygen vacancy-ordered phases and then decompose when heated to 1000°C under atmospheres with pO2 as low as 10-5 atm.

High-temperature structural study of decagonal Al–Cu–Rh

2014 ◽  
Vol 70 (2) ◽  
pp. 306-314 ◽  
Author(s):  
Pawel Kuczera ◽  
Janusz Wolny ◽  
Walter Steurer
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Structural Study ◽  
Structural Disorder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Decagonal Phase ◽  
Comparative Structure ◽  
The Stability

The structure of decagonal Al–Cu–Rh has been studied as a function of temperature byin-situsingle-crystal X-ray diffraction in order to contribute to the discussion on energy or entropy stabilization of quasicrystals. The experiments were performed at 293, 1223, 1153, 1083 and 1013 K. A common subset of 1460 unique reflections was used for the comparative structure refinements at each temperature. A comparison of the high-temperature datasets suggests that the best quasiperiodic ordering should exist between 1083 and 1153 K. However, neither the refined structures nor the phasonic displacement parameter vary significantly with temperature. This indicates that the phasonic contribution to entropy does not seem to play a major role in the stability of this decagonal phase in contrast to other kinds of structural disorder, which suggests that, in this respect, this decagonal phase would be similar to other complex intermetallic high-temperature phases.

An improved goniometer head for high-temperature single-crystal X-ray diffraction

1999 ◽  
Vol 32 (4) ◽  
pp. 824-826 ◽  
Author(s):  
Patrice Delarue ◽  
Michel Jannin
Keyword(s):  
High Temperature ◽  
Data Collection ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Charge Coupled Device ◽  
X Ray ◽  
Space Saving ◽  
The Stability ◽  
Ccd Detectors ◽  
Goniometer Head

A reliable and inexpensive goniometer head has been designed. Its stability, resulting from its compact construction, makes it very suitable for accurate measurements. Moreover, its space-saving design facilitates its application in X-ray data collection using charge-coupled device (CCD) detectors. This head has been improved for high-temperature measurements and has been tested by comparison of accurate K0.88Rb0.12TiOPO4data collected both at room temperature and at 973 K on the same crystal. The excellent structure results obtained at 973 K during the 360 h of measurements prove the stability of the goniometer head.

scholarly journals A high-pressure and high-temperature gas-loading system for the study of conventional to real industrial sized samples in catalysed gas/solid and liquid/solid reactions

2014 ◽  
Vol 47 (1) ◽  
pp. 245-255 ◽  
Author(s):  
Jerome Andrieux ◽  
Christophe Chabert ◽  
Anthony Mauro ◽  
Hugo Vitoux ◽  
Bernard Gorges ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Pressure ◽  
High Temperature ◽  
Gas Flow ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Reaction Cell ◽  
X Ray ◽  
Loading System ◽  
High Temperature Gas

A high-pressure–high-temperature gas-loading system (GLS) is described for combinedoperandoX-ray diffraction and mass spectrometry investigations during catalysed gas/solid or liquid/solid reactions. The pressure cell consists of a single-crystal sapphire tube which serves as both high-pressure container and reaction cell, with up to 6 mm inner diameter. The system can operate in two different configurations, under either static high pressure or dynamic pressurized flow. The transportable reaction cell can be filled under inert atmosphere inside a glove box, enabling studies with oxygen-sensitive compounds to be conducted. The five main benefits of this system can be summarized as follows: (i) the temperature, pressure and gas-flow ranges of 298–1273 K, 10−3 mbar–200 bar (0.1–2 × 107 Pa) and 0–1 l min−1, respectively, (ii) the combination of different gases, (iii) the flexibility of the cell design, (iv) the full rotation of the pressurized cell, and (v) the combination of X-ray diffraction and mass spectrometry as analytical tools. These key points open new possibilities for studying the evolution of catalysts or compounds from a fundamental point of view as well as for industrial applications, in both cases inoperandoconditions.

Thermal Expansion Behaviour of Inconel-690 by In Situ High Temperature X-Ray Diffraction

2015 ◽  
Vol 830-831 ◽  
pp. 367-370 ◽  
Author(s):  
D. Ramachandran ◽  
A.M. Kamalan Kirubaharan ◽  
Arul Maximus Rabel ◽  
P. Kuppusami
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Thermal Exposure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Temperature Range ◽  
High Temperature Xrd ◽  
Inconel 690 ◽  
The Stability

Ni-Cr-Fe based alloy Inconel 690 is widely used in power plant, marine, chemical and nuclear applications due to its excellent mechanical properties, resistance to thermal creep deformation, good thermal stability and resistance to corrosive and oxidizing environments. In order to study the microstructure of the alloy and the precipitates formation during thermal exposure, the alloy was subjected to in-situ high temperature X-ray diffraction technique (HT-XRD) in the temperature range 298-1273K. Results of high temperature XRD patterns show (111), (200), (220) and (311) reflections confirming the stability of fcc structure in the temperature of investigation. With increase in the temperature, a shift in peak positions towards lower 2θ values due to lattice expansion was noticed. The average thermal expansion coefficient (TEC) of the alloy increased from 1.33 x 10-5 K-1 to 1.53 x 10-5 K-1 in the temperature range 298-1273 K. Scanning electron microscopy indicates austenitic grains of sizes in the range 100-150μm and chromium carbide precipitate at grain boundaries after the HT-XRD heat treatment.

Fractionation of polymethylene chains: An electron crystallographic investigation

1986 ◽  
Vol 44 ◽  
pp. 794-795
Author(s):  
Douglas L. Dorset
Keyword(s):  
Cross Section ◽  
Binary Systems ◽  
Linear Chain ◽  
Pure Component ◽  
Organic Substrates ◽  
Crystallographic Investigation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Sizes ◽  
The Stability

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

High temperature X-ray diffraction investigation of an aluminium-silicon-corundum system

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 369-374 ◽  
Author(s):  
D. Garipoli ◽  
P. Bergese ◽  
E. Bontempi ◽  
M. Minicucci ◽  
A. Di Cicco ◽  
...  
Keyword(s):  
High Temperature ◽  
X Ray Diffraction ◽  
X Ray
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