scholarly journals ADVANTAGES AND DISADVANTAGES OF DIFFERENT METHODS FOR STUDYING THE PHASE-STRUCTURAL STATES OF MATERIALS (A REVIEW)

2021 ◽  
pp. 51-55
Author(s):  
Hanna Kniazieva (Postelnyk) ◽  
Serhii Kniaziev ◽  
Mykola M. Tkachuk ◽  
Natalia Pinchuk
Keyword(s):  
Phase Composition ◽  
Materials Science ◽  
Phase Identification ◽  
Structural Studies ◽  
Electronic Database ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Specialized Software ◽  
Modern Methods ◽  
Diffraction Patterns

The paper provides a brief overview of the standard capabilities of X-ray techniques for studying materials with examples of modern performance of elemental and structural studies. X-ray research methods make it possible to reveal the elemental and phase-structural state. Thanks to modern software and electronic databases, the use of previously complex techniques is becoming simpler and more accessible. To illustrate the solution of specific problems, several examples of obtaining and decoding diffraction patterns and identifying the phase composition of the coating and ceramic material are given. An example of work in modern specialized software for acceleration and automation of phase identification is shown. For clarity, an example of identifying phases using electronic database cards is presented, which is still used today for manual decoding.  The practice of interaction between researchers shows that even specialists in the field of X-ray structural analysis are not always aware of modern methods of processing and decoding the obtained data. The possibilities and algorithm of action in research can be interesting for students, engineers, researchers of materials science and mechanical engineering profile. Keywords: microscopy, X-raystructural analysis, X-rayfluorescence analysis

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

X-Ray Absorption Spectroscopy as an in-situ Tool in Materials Science

1997 ◽  
Vol 502 ◽  
Author(s):  
T. Ressler ◽  
Joe Wong ◽  
W. Metz
Keyword(s):  
Absorption Spectroscopy ◽  
Materials Science ◽  
Ex Situ ◽  
Structural Studies ◽  
Time Resolved ◽  
X Ray ◽  
Complementary Techniques ◽  
X Ray Absorption ◽  
Established Technique

ABSTRACTIn addition to being an established technique for ex-situ structural studies, x-ray absorption spectroscopy (XAS) has recently been realized to be a powerful tool for in-situ time-resolved investigations in materials science. This paper describes two complementary techniques: quick-scanning EXAFS (QEXAFS) and energy-dispersive XAS (DXAS) which offer time resolution in the seconds and milliseconds range, respectively. Formation of a heterogeneous catalyst from a solid-state reaction of a precursor is presented as an example of a time-resolved XAS application.

scholarly journals Clay minerals in sediments from contact zones with basalt sills

2019 ◽  
pp. 234-247
Author(s):  
V. B. Kurnosov ◽  
B. A. Sakharov ◽  
A. R. Geptner ◽  
Yu. I. Konovalov ◽  
E. O. Goncharov
Keyword(s):  
Phase Composition ◽  
Clay Minerals ◽  
Mixed Layer ◽  
Gulf Of California ◽  
Layered Silicates ◽  
Total Thickness ◽  
Upper Pleistocene ◽  
X Ray ◽  
Diffraction Patterns ◽  
Trioctahedral Smectite

Clay minerals (fraction <0.001 mm) of Upper Pleistocene clayey-sandy-silty sediments recovered by DSDP Holes 481 and 481A in the Northern Trough, Guaymas Basin, Gulf of California, were studied by X-ray based on the modeling of diffraction patterns and their comparison with experimental diffractograms. Terrigenous clay minerals are represented mainly by dioctahedral micaceous varieties (mixed-layer disordered illite-smectites, illite) with the chlorite admixture and by kaolinite in the upper section of unaltered sediments. Intrusion of hot basalt sills (total thickness of the complex is about 27 m) provoked alterations in the phase composition of clay minerals in sediments (7.5 m thick) overlying the sill complex. These sediments include newly formed triooctahedral layered silicates (mixed-layer chlorite-smectites, smectite). Sediments inside the sill complex include trioctahedral mixed-layer mica-smtctite-vermiculite or trioctahedral smectite. The trioctahedral mixed-layer chlorite-smectite coexisting with smectite was found in a single sample of the same complex.

Bayesian approach to powder phase identification

2017 ◽  
Vol 50 (3) ◽  
pp. 776-786 ◽  
Author(s):  
Alexander Mikhalychev ◽  
Alex Ulyanenkov
Keyword(s):  
Phase Identification ◽  
X Ray Diffraction ◽  
X Ray ◽  
Prior Probabilities ◽  
Manual Search ◽  
Diffraction Patterns ◽  
Qualitative Phase ◽  
Established Technique ◽  
Standard Strategy ◽  
Powder Phase

Identification of unknown materials using X-ray powder diffraction patterns is a commonly used and well established technique with a number of proved implementations. Generally, qualitative phase analysis of X-ray diffraction data includes ranking of candidate phases on the basis of similarity of their diffraction patterns to the measured one. A standard strategy of such a ranking by algorithmization of manual search criteria may become inconvenient for modification and adaptation for problems that are not supported by our intuition. Here, the problem of providing physically grounded expressions for candidate phase ranking is addressed. The approach is based on calculation of Bayesian posterior probabilities of the phases' presence in the sample. The choice of the expressions for the prior probabilities for deviations of phases' diffraction patterns from database entries determines the degree of physical detailing and may be made according to the specifics of the problem being solved. It is shown that even for simple exponential expressions for prior probabilities the approach identifies the phases for IUCr round robin cases correctly, as well as ensuring sufficient robustness of the results with respect to diffraction peak shifts and intensity variations.

scholarly journals Using a non-monochromatic microbeam for serial snapshot crystallography

2013 ◽  
Vol 46 (3) ◽  
pp. 791-794 ◽  
Author(s):  
Catherine Dejoie ◽  
Lynne B. McCusker ◽  
Christian Baerlocher ◽  
Rafael Abela ◽  
Bruce D. Patterson ◽  
...  
Keyword(s):  
Laser Source ◽  
Single Shot ◽  
Structural Studies ◽  
Proof Of Concept ◽  
Partial Reflection ◽  
Crystalline Materials ◽  
X Ray ◽  
Reflection Measurement ◽  
Type Zeolite ◽  
Diffraction Patterns

The new X-ray free-electron laser source (SwissFEL) that is currently being developed at PSI will provide a broad-bandpass mode with an energy bandwidth of about 4%. By using the full energy range, a new option for structural studies of crystalline materials may become possible. The proof of concept of broad-bandpass diffraction presented here is based on Laue single-crystal microdiffraction and the experimental setup on BL12.3.2 at the Advanced Light Source in Berkeley. Diffraction patterns for 100 randomly oriented stationary crystallites of theMFI-type zeolite ZSM-5 were simulated assuming several bandwidths, and the statistical and structural results are discussed. With a 4% energy bandwidth, the number of reflection intensities measured in a single shot is significantly higher than with monochromatic radiation. Furthermore, the problem of partial reflection measurement, which is inherent to the monochromatic mode with stationary crystals, can be overcome.

Characteristic of Crystallite Sizes and Lattice Deformations Changes in the Oxide Layer Formed on Steel Operated for a Long Time at an Elevated Temperature

2013 ◽  
Vol 203-204 ◽  
pp. 204-207 ◽  
Author(s):  
Monika Gwoździk
Keyword(s):  
Phase Composition ◽  
Elevated Temperature ◽  
Oxide Layer ◽  
Flue Gas ◽  
Phase Identification ◽  
X Ray ◽  
Term Operation ◽  
Long Time ◽  
Crystallite Sizes

The paper presents results of studies on the phase composition, crystallite sizes and lattice deformations of oxide layers formed during a long-term operation on X10CrMoVNb9-1 steel. Test specimens were taken from a live steam pipeline operated at 535°C for 70,000 hours. X-ray studies were carried out on the tube outside surface (on the flue gas side), then the layer’s surface was polished and the diffraction measurements repeated to reveal differences in the originated oxides layer. X-ray phase analysis was performed using a SEIFFERT 3003 T/T X-ray diffractometer, with a cobalt tube of λCo= 0.17902nm wavelength. crystallographic database were used for the phase identification.

An automated procedure for the correction of background due to inelastic scattering in electron diffraction patterns

1977 ◽  
Vol 10 (1) ◽  
pp. 64-66 ◽  
Author(s):  
R. D. B. Fraser ◽  
T. P. Macrae ◽  
E. Suzuki ◽  
P. A. Tulloch
Keyword(s):  
Electron Diffraction ◽  
Inelastic Scattering ◽  
Digital Processing ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Fibrous Polymers

The use of electron diffraction in structural studies of fibrous polymers is complicated by the presence of an intense background associated with inelastic scattering. A method of digital processing is described which effectively removes the undesirable features of this background. The method is also applicable in low-angle X-ray diffraction studies.

Materials-science applications of novel methods for the analysis of electron-diffraction patterns

1992 ◽  
Vol 50 (2) ◽  
pp. 1444-1445
Author(s):  
G.J.C. Carpenter ◽  
Y. Le Page
Keyword(s):  
Electron Diffraction ◽  
Materials Science ◽  
Interplanar Spacing ◽  
Convergent Beam Electron Diffraction ◽  
Phase Identification ◽  
Primitive Cell ◽  
Transmitted Beam ◽  
Analytical Microscopy ◽  
Diffraction Patterns ◽  
Convergent Beam

Electron diffraction provides a highly effective method for the identification of microscopic, crystalline phases in the solid state. The following examples are given to illustrate applications of three new analytical methods to typical problems in analytical microscopy of materials.Phase identification using convergent beam electron diffraction (CBED) patterns can often be simplified when measurements from the zero and high order Laue zones (ZOLZ and HOLZ) are combined to calculate the primitive cell volume, Vc. Defining g1 and g2 as two primitive vectors in the ZOLZ (e.g. two non-collinear spots closest to the transmitted beam) the volume of the primitive reciprocal cell is;Vc* = g1 × g2 . H,where H is the reciprocal interplanar spacing calculated from the diameter(s) of the HOLZ ring(s). This calculation can be performed without indexing the pattern. The inverse of Vc* is the volume of the primitive cell, Vc, which is easily compared with literature data for possible phases.

The Quality of X-ray Diffraction Standards for Phosphate Minerals and the Degree of Success in Computer Identification

1984 ◽  
Vol 28 ◽  
pp. 305-308
Author(s):  
Frank N. Blanchard
Keyword(s):  
Data Base ◽  
Powder Diffraction ◽  
Data Reduction ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns ◽  
Computer Identification

Sixty-five years ago Hull first described X-ray powder diffraction as a means of phase identification, and 45 years ago Hannawalt and co-workers compiled the first catalogue of powder diffraction patterns, which has evolved into a file of about 44,000 patterns (the X-ray Powder Diffraction File or PDF). The Hannawalt method of manually searching the PDF is a time-tested, effective tool in seeking a match between an unknown pattern and its correct counterpart(s) in the PDF. Recently, computerized powder diffractometers with software to perform data reduction and search the PDF have become relatively common, and these systems offer tremendous potential for rapid and accurate phase identification in simple and complex systems where the data base may include 44,000 patterns.

Determination of Lattice Parameters by the Kossel and Divergent X-Ray Beam Techniques

1967 ◽  
Vol 11 ◽  
pp. 345-358 ◽  
Author(s):  
A. Lutts
Keyword(s):  
Historical Review ◽  
Lattice Parameters ◽  
General Relationship ◽  
Cubic Crystals ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Diffraction Patterns ◽  
Classical Means ◽  
High Degree ◽  
Beam Patterns

AbstractThe principal aim of this article is to develop in a clear and orderly manner a general relationship and show how it can be used to determine with a high degree of precision lattice parameters of tetragonal and hexagonal as well as cubic crystals. The introduction and extensive use of electron-probe microanalyzers provides a ready-made means of obtaining both Kossel and divergent X-ray beam patterns which could previously be produced only with specially constructed X-ray tubes. The present ease of their production as well as the continuing need for precise lattice parameters for the study of many problems associated with crystallized solids has stimulated a renewed interest in these two techniques. As has been recently shown by several experimental results limited to cubic crystals, these techniques are capable of giving lattice parameters with the same degree of precision as those obtained by the more classical means. The development of the general relationship is preceded by a brief historical review, a discussion of the relative merits of the methods, a short description of the nature of the diffraction patterns, and the geometrical conditions necessary for realizing precision parameter measurements. In conclusion, the advantages and disadvantages of the Kossel and divergentbeam methods compared with those of the classical powder techniques are enumerated and discussed.

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