Micro X-ray diffraction on capillary powder samples: a novel and effective technique for overcoming preferred orientation

2001 ◽  
Vol 34 (5) ◽  
pp. 663-665 ◽  
Author(s):  
P. Bergese ◽  
E. Bontempi ◽  
I. Colombo ◽  
L. E. Depero
Keyword(s):  
Structural Parameters ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
Rapid Preparation ◽  
X Ray ◽  
Polymeric Carriers ◽  
Powder Samples ◽  
Promising Solution ◽  
Diffraction Patterns ◽  
Analytical Approaches

In past years, both experimental and analytical approaches have been developed for eliminating preferred orientation effects on powder X-ray diffraction patterns. The state of the art does not allow one to face the problem without difficult sample treatments, mechanical randomization, pole-figure study or pattern fitting based on the Rietveld approach. These methods are time consuming or need the knowledge of all the structural parameters, and, moreover, must be managed by specialized operators. Besides, none of the above techniques can be applied to powder samples of drugs loaded into polymeric carriers, the diffraction patterns of which present a structured amorphous halo from which the crystalline drug peaks rise up. In this paper, it is shown that micro X-ray diffraction on capillary powder samples, combined with a two-dimensional detector, is a promising solution to preferred orientation problems, since it provides easy and rapid preparation of randomly oriented powder samples, fast measurements (acquisition times of a few minutes) and correct powder diffraction patterns.

Sinterbility of (Bi4-xLax)Ti3O12 Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 841-844 ◽  
Author(s):  
Pasinee Siriprapa ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon
Keyword(s):  
Grain Orientation ◽  
Sintering Temperature ◽  
Orthorhombic Phase ◽  
Preferred Orientation ◽  
Doping Content ◽  
X Ray Diffraction ◽  
Microstructural Investigation ◽  
X Ray ◽  
Lanthanum Titanate ◽  
Diffraction Patterns

This research studied the effects of sintering temperature and La3+ doping content on phase, microstructure and densification of bismuth lanthanum titanate (Bi4-xLaxTi3O12; BLT) ceramics when x = 0, 0.25, 0.5, 0.75 and 1.0, respectively. The BLT powders were prepared using a mixed-oxide method. The mixtures were calcined at 750°C for 4 h before being pressed and sintered at 1000-1150°C for 4 h. The result of phase analysis by X–ray diffraction (XRD) indicated the existence of orthorhombic phase for all sintering temperatures. The XRD peak intensities of the ceramics showed preferred orientation of a particular set of {00l}-type planes. The ceramics mainly composed of plate-like grains. Increasing the sintering temperature increased grain size and increased preferred grain orientation. The present of La3+ in BLT ceramics reduced preferred orientation especially at higher sintering temperature. Results of microstructural investigation agreed well with X-ray diffraction patterns.

In situreaction furnace for real-time XRD studies

2012 ◽  
Vol 20 (1) ◽  
pp. 194-196 ◽  
Author(s):  
Pietro Riello ◽  
Andrea Lausi ◽  
Jennifer Macleod ◽  
Jasper Rikkert Plaisier ◽  
Giulio Zerauschek ◽  
...  
Keyword(s):  
Reaction Chamber ◽  
Radiative Heating ◽  
Materials Characterization ◽  
Imaging Plate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Samples ◽  
Flow Through ◽  
Xrd Studies ◽  
Diffraction Patterns

The new furnace at the Materials Characterization by X-ray Diffraction beamline at Elettra has been designed for powder diffraction measurements at high temperature (up to 1373 K at the present state). Around the measurement region the geometry of the radiative heating element assures a negligible temperature gradient along the capillary and can accommodate either powder samples in capillary or small flat samples. A double capillary holder allows flow-through of gas in the inner sample capillary while the outer one serves as the reaction chamber. The furnace is coupled to a translating curved imaging-plate detector, allowing the collection of diffraction patterns up to 2θ ≃ 130°.

Lattice and Peak Profile Parameters in GIXD Technique

2007 ◽  
Vol 130 ◽  
pp. 281-286 ◽  
Author(s):  
Tomasz Goryczka ◽  
Grzegorz Dercz ◽  
Lucjan Pająk ◽  
Eugeniusz Łągiewka
Keyword(s):  
Structural Parameters ◽  
Incident Beam ◽  
Half Width ◽  
Diffraction Line ◽  
Beam Angle ◽  
X Ray Diffraction ◽  
Parallel Beam ◽  
X Ray ◽  
Diffraction Patterns ◽  
Α Angle

Grazing incident X-ray diffraction technique was applied to determine the influence of incident beam angle (α angle) on structural parameters as well as peak profile. X-ray diffraction patterns were registered in asymmetrical geometry, in which a parallel beam was formed by Soller and divergence slits. Lowering of the α angle results in accuracy decrease of lattice parameters as well as in significant broadening of a half-width of X-ray diffraction line.

X-ray diffraction patterns of LuNi2B2C and YNi2B2C

1996 ◽  
Vol 11 (2) ◽  
pp. 88-90 ◽  
Author(s):  
W. Wong-Ng ◽  
R. Cava ◽  
J. J. Krajewski ◽  
W. F. Peck
Keyword(s):  
Preferred Orientation ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Arc Melting ◽  
Melting Technique ◽  
Diffraction Patterns

Reference X-ray diffraction patterns for the quarternary intermetallic superconductor phases of compositions LuNi2B2C and YNi2B2C are reported. Both materials were synthesized by the arc-melting technique. The patterns of these metallic phases exhibit preferred orientation in an ordinarily pressed sample, which was minimized through special specimen preparation. The observed intensities and the calculated values for both phases agree reasonably well with each other. Both compounds were refined in the space group I4/mmm, with a=3.4647(1) Å and c=10.6330(4) Å for LuNi2B2C and a=3.5271(1) Å, c=10.5361(7) Å for YNi2B2C.

scholarly journals Single-crystal diffraction data from powder samples via SFX

2014 ◽  
Vol 70 (a1) ◽  
pp. C1449-C1449
Author(s):  
Tao Zhang ◽  
Shifeng Jin ◽  
Yuanxin Gu ◽  
Yao He ◽  
Haifu Fan
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Monte Carlo Integration ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
Single Experiment ◽  
X Ray ◽  
Powder Samples ◽  
Diffraction Patterns

With the serial femtosecond crystallography (SFX) [1] using hard X-ray free-electron laser as light source, it is possible to obtained three-dimensional single-crystal diffraction data from powder samples consisting of submicron crystal grains. This offers two advantages. First, complicated crystal structures far beyond the ability of powder X-ray diffraction analysis now can be solved easily; second, mixtures of two or more crystalline components can be examined in a single experiment. The percentage of each component can be determined accurately and the crystal structure of them can be solved readily. Simulating calculations were performed with a mixture of two different kinds of zeolites. The program suite CrystFEL [2] was used for simulating SFX diffraction patterns, diffraction indexing and Monte-Carlo integration of diffraction intensities. The program suite SHELX [3] was used for structure determination. Satisfactory results have been obtained and will be discussed in detail.

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 Structural Analysis of Interstratified Illite-Smectite by the Rietveld Method

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 244
Author(s):  
Xiaoli Wang ◽  
Hejing Wang
Keyword(s):  
Structural Information ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Structural Parameter ◽  
X Ray Diffraction ◽  
Recursive Structure ◽  
X Ray ◽  
Powder Samples ◽  
Xrd Patterns

Rietveld method is a powerful tool in obtaining structural information of clay minerals by using of X-ray diffraction (XRD) patterns. However, the interstratified illite-smectites (I-S) show various stacking defects preventing the direct application of this method. It was shown that the Rietveld method combined with a recursive structure-factor calculation can be used for describing the stacking disorder of I-S. In this study, a series of samples with different stacking sequences and different proportions of layer types were chosen to verify the applicability of Rietveld method in determination of structural parameters of I-S. The Rietveld refinements were carried out on powder samples and oriented specimens in air-dry (AD) and ethylene glycol (EG) state. The structural information obtained by X-ray fluorescence (XRF) and thermal analysis were used as an independent test of the reliability of the refinements. The refined and experimental results were compared systematically and the relationship between structural parameter was discussed. For powder and oriented specimens, the refined results of occupancies of potassium and iron and the proportion of illitic layers showed consistent results. The refined value of cis-vacant layers was in good agreement with the experimental data. The reliability of the refinements increased with increasing proportion of illitic layers.

scholarly journals Variations to Spin Crossover in [FexZn(1−x)(Me1,3bpp)2(ClO4)2] molecular alloys examined by Magnetometry and Single Crystal X-Ray Diffraction

2021 ◽  
Author(s):  
Rosa Diego ◽  
Olivier Roubeau ◽  
Guillem Aromí
Keyword(s):  
Single Crystal ◽  
Spin Crossover ◽  
Structural Parameters ◽  
Structural Data ◽  
X Ray Diffraction ◽  
Chemical Pressure ◽  
X Ray ◽  
Diffraction Patterns ◽  
Gradual Variation ◽  
Composition Changes

Spin crossover (SCO) active solid solutions with formula [FexZn1-x(Me1,3bpp)2](ClO4)2 (x = 0.10, 0.15, 0.22, 0.33, 0.41, 0.48, 0.56 and 0.64, Me1,3bpp is a bis-pyrazolylpyridine) and the complex [Zn(Me1,3bpp)2](ClO4)2 have been prepared and characterized by single crystal X-ray diffraction. The structural data and the powder diffraction patterns of all the compounds have been compared with the reported isostructural molecular crystal [Fe(Me1,3bpp)2](ClO4)2. Increasing amounts of Zn diminishes monotonically the cooperativity of the SCO of the parent Fe(II) complex (T1/2=183 K) and cause a decrease of T1/2 in line with the negative chemical pressure exerted by the Zn(II) complexes on the Fe(II) lattice. The gradual variation of the magnetic properties as the composition changes are paralleled by the evolution of the structural parameters at the molecular, intermolecular and crystal lattice scales. Thermal trapping of a portion of the Fe(II) centers of these alloys by quenching the crystals to 2 K unveils that, upon warming, the temperature of relaxation of the metastable states is almost constant for all compositions.

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