scholarly journals Correction of Integrated X-Ray Intensities for Preferred Orientation in Hexagonal Close-Packed Powders Using Edxrd

1980 ◽  
Vol 4 (2) ◽  
pp. 63-71 ◽  
Author(s):  
J. Kivilä ◽  
E. Laine ◽  
S. Parviainen
Keyword(s):  
Density Distribution ◽  
Polar Axis ◽  
Preferred Orientation ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Integrated Intensities

It is shown that energy-dispersive x-ray diffraction (EDXRD) method can be used for correction of integrated intensities for preferred orientation in hexagonal close-packed powders. The theory is based upon examination of the polar axis density distribution and upon the use of hexagonal harmonics in its representation. The reflexion method by Schulz added with defocusing correction was used. Measurements were carried out on three zinc samples with different degrees of orientation, the largest correction being 54 percent.

scholarly journals A Study of Preferred Orientation by Energy-Dispersive X-Ray Diffraction

1977 ◽  
Vol 2 (4) ◽  
pp. 243-251 ◽  
Author(s):  
E. Laine ◽  
J. Kivilä ◽  
I. Lähteenmäki
Keyword(s):  
Density Distribution ◽  
Diffraction Method ◽  
Polar Axis ◽  
Preferred Orientation ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
Powder Specimen ◽  
X Ray ◽  
Aluminium Powder ◽  
Energy Dispersive Diffraction

The influence of preferred orientation on integrated x-ray intensities in powder specimen using energy-dispersive diffraction method is investigated. The theory used is based upon examination of the polar axis density distribution. The measurements were carried out using the Schulz technique added with defocusing correction. Experimental results are given for three aluminium powder specimens.

scholarly journals Quantitative Determination of Preferred Orientation by Energy-Dispersive X-Ray Diffraction

1976 ◽  
Vol 2 (2) ◽  
pp. 95-111 ◽  
Author(s):  
L. Gerward ◽  
S. Lehn ◽  
G. Christiansen
Keyword(s):  
Quantitative Determination ◽  
Rolling Texture ◽  
Tension Test ◽  
Preferred Orientation ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fibre Texture

The use of energy-dispersive X-ray diffraction for quantitative determination of preferred orientations in polycrystalline specimens is analysed. The method is applied to determinations of rolling texture and fibre texture. The adaptability of the method to in situ studies is demonstrated by observations of texture changes simultaneous with the deformation of a specimen in a tension test.

scholarly journals The suppression of fluorescence peaks in energy-dispersive X-ray diffraction

2014 ◽  
Vol 47 (5) ◽  
pp. 1708-1715 ◽  
Author(s):  
G. M. Hansford ◽  
S. M. R. Turner ◽  
D. Staab ◽  
D. Vernon
Keyword(s):  
Excitation Energy ◽  
Preferred Orientation ◽  
Energy Dispersive ◽  
Source Spectrum ◽  
Natural State ◽  
X Ray Diffraction ◽  
Scattering Angle ◽  
X Ray ◽  
Back Reflection ◽  
Diffraction Peaks

A novel method to separate diffraction and fluorescence peaks in energy-dispersive X-ray diffraction (EDXRD) is described. By tuning the excitation energy of an X-ray tube source to just below an elemental absorption edge, the corresponding fluorescence peaks of that element are completely suppressed in the resulting spectrum. SinceBremsstrahlungphotons are present in the source spectrum up to the excitation energy, any diffraction peaks that lie at similar energies to the suppressed fluorescence peaks are uncovered. This technique is an alternative to the more usual method in EDXRD of altering the scattering angle in order to shift the energies of the diffraction peaks. However, in the back-reflection EDXRD technique [Hansford (2011).J. Appl. Cryst.44, 514–525] changing the scattering angle would lose the unique property of insensitivity to sample morphology and is therefore an unattractive option. The use of fluorescence suppression to reveal diffraction peaks is demonstrated experimentally by suppressing the Ca Kfluorescence peaks in the back-reflection EDXRD spectra of several limestones and dolomites. Three substantial benefits are derived: uncovering of diffraction peak(s) that are otherwise obscured by fluorescence; suppression of the Ca Kescape peaks; and an increase in the signal-to-background ratio. The improvement in the quality of the EDXRD spectrum allows the identification of a secondary mineral in the samples, where present. The results for a pressed-powder pellet of the geological standard JDo-1 (dolomite) show the presence of crystallite preferred orientation in this prepared sample. Preferred orientation is absent in several unprepared limestone and dolomite rock specimens, illustrating an advantage of the observation of rocks in their natural state enabled by back-reflection EDXRD.

Parallel-beam X-ray diffractometry using X-ray guide tubes

2000 ◽  
Vol 33 (2) ◽  
pp. 389-391 ◽  
Author(s):  
Toyoko Yamanoi ◽  
Hiromoto Nakazawa
Keyword(s):  
Large Diameter ◽  
Preferred Orientation ◽  
X Rays ◽  
X Ray Diffraction ◽  
Parallel Beam ◽  
X Ray ◽  
Orientation Effects ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Integrated Intensities

A parallel-beam X-ray diffraction geometry using X-ray guide tubes is proposed to eliminate preferred-orientation effects in powder X-ray diffraction (XRD) patterns and for new applications of XRD. A bundle of X-ray guide tubes (polycapillaries) is used to provide an intense quasi-parallel (approximately 0.2° divergence) and large-diameter (approximately 20 mm) beam of X-rays needed for parallel-beam diffractometry. Mica and silicon particles were agitated inside a cylindrical chamber by a steady flow of N2gas so that they were randomly oriented. The quasi-parallel incident X-ray beam passed through the cloud of floating particles. The diffracted X-rays were detected using a standard 2θ diffractometer. The integrated intensities observed agree well with those calculated from the known model of the crystal structure. This result demonstrates that this type of diffractometry is capable of avoiding preferred-orientation effects and of collecting XRD data for moving powder samples.

scholarly journals Defocusing in the Reflexion Technique for the Determination of Preferred Orientation Using EDXRD

1982 ◽  
Vol 4 (4) ◽  
pp. 201-210
Author(s):  
J. Kivilä ◽  
E. Laine
Keyword(s):  
Preferred Orientation ◽  
Slit Width ◽  
Energy Dispersive ◽  
Bragg Angle ◽  
X Ray Diffraction ◽  
X Ray

The defocusing effect in the reflexion technique for the determination of the preferred orientation using energy-dispersive x-ray diffraction (EDXRD) method is studied experimentally. The measurements show that the defocusing effect is dependent on the Bragg angle, the receiving slit width, the reflexion hkl and the metallurgical condition of the specimen. The defocusing correction or at least the optimizing of the measuring geometry is found to be necessary in quantitative texture measurements.

Structural Characterization of Gallbladder Stones Using Energy Dispersive X-ray Spectroscopy and X-ray Diffraction

2018 ◽  
Vol 21 (7) ◽  
pp. 495-500 ◽  
Author(s):  
Hassan A. Almarshad ◽  
Sayed M. Badawy ◽  
Abdalkarem F. Alsharari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Major Health Problem ◽  
X Ray ◽  
Gallbladder Stones ◽  
Pure Cholesterol ◽  
Scanning Electron

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.

Selective catalytic reduction of NO by Co-Mn based nanocatalysts

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vahid Zabihi ◽  
Mohammad Hasan Eikani ◽  
Mehdi Ardjmand ◽  
Seyed Mahdi Latifi ◽  
Alireza Salehirad
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Energy Dispersive ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
Acidic Sites ◽  
Temperature Window ◽  
Temperature Programmed

Abstract One of the most significant aspects in selective catalytic reduction (SCR) of nitrogen oxides (NOx) is developing suitable catalysts by which the process occurs in a favorable way. At the present work SCR reaction by ammonia (NH3-SCR) was conducted using Co-Mn spinel and its composite with Fe-Mn spinel, as nanocatalysts. The nanocatalysts were fabricated through liquid routes and then their physicochemical properties such as phase composition, degree of agglomeration, particle size distribution, specific surface area and also surface acidic sites have been investigated by X-ray diffraction, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD) analysis techniques. The catalytic activity tests in a temperature window of 150–400 °C and gas hourly space velocities of 10,000, 18,000 and 30,000 h−1 revealed that almost in all studied conditions, CoMn2O4/FeMn2O4 nanocomposite exhibited better performance in SCR reaction than CoMn2O4 spinel.

scholarly journals Energy dispersive X-ray diffraction (EDXRD) for operando materials characterization within batteries

2020 ◽  
Vol 22 (37) ◽  
pp. 20972-20989 ◽  
Author(s):  
Amy C. Marschilok ◽  
Andrea M. Bruck ◽  
Alyson Abraham ◽  
Chavis A. Stackhouse ◽  
Kenneth J. Takeuchi ◽  
...  
Keyword(s):  
Materials Characterization ◽  
Energy Dispersive ◽  
System Level ◽  
X Ray Diffraction ◽  
X Ray ◽  
Non Destructive ◽  
Non Destructive Characterization

This review highlights the efficacy of EDXRD as a non-destructive characterization tool in elucidating system-level phenomena for batteries.

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