Using X-ray diffraction in forensic science

2007 ◽  
Vol 222 (3-4) ◽  
Author(s):  
Marek Kotrlý
Keyword(s):  
Quantitative Analysis ◽  
Forensic Science ◽  
Phase Analysis ◽  
Analytical Methods ◽  
Small Volume ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Phase Analysis ◽  
Forensic Expert ◽  
Non Destructive

The majority of expert examination in forensic science is concerned with comparison, determination, and description of diversified samples. X-ray diffraction (powdered and/or single crystal) is bringing big benefits and analytical possibilities into forensic expert work, which are not easily provided by other methods. XRD methods are used in combination with other analytical methods (SEM with EDS/WDS, micro XRF, optical microscopy, FTIR, etc.).Importance of XRD phase analysis in forensic science lies namely in: analysis of relatively small-volume samples, relatively non-destructive, exact phase analysis, quantitative analysis (in majority of cases). And method is conclusive for a court.

scholarly journals Quantitative Phase Analysis by X-ray Diffraction—Doping Methods and Applications

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27 ◽  
Author(s):  
Stanko Popović
Keyword(s):  
Quantitative Analysis ◽  
Phase Analysis ◽  
Powder Diffraction ◽  
Phase Fraction ◽  
Quantitative Phase Analysis ◽  
Intermetallic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Phase

X-ray powder diffraction is an ideal technique for the quantitative analysis of a multiphase sample. The intensities of diffraction lines of a phase in a multiphase sample are proportional to the phase fraction and the quantitative analysis can be obtained if the correction for the absorption of X-rays in the sample is performed. Simple procedures of quantitative X-ray diffraction phase analysis of a multiphase sample are presented. The matrix-flushing method, with the application of reference intensities, yields the relationship between the intensity and phase fraction free from the absorption effect, thus, shunting calibration curves or internal standard procedures. Special attention is paid to the doping methods: (i) simultaneous determination of the fractions of several phases using a single doping and (ii) determination of the fraction of the dominant phase. The conditions to minimize systematic errors are discussed. The problem of overlapping of diffraction lines can be overcome by combining the doping method (i) and the individual profile fitting method, thus performing the quantitative phase analysis without the reference to structural models of particular phases. Recent suggestions in quantitative phase analysis are quoted, e.g., in study of the decomposition of supersaturated solid solutions—intermetallic alloys. Round Robin on Quantitative Phase Analysis, organized by the IUCr Commission on Powder Diffraction, is discussed shortly. The doping methods have been applied in various studies, e.g., phase transitions in titanium dioxide, biomineralization processes, and phases in intermetallic oxide systems and intermetallic alloys.

Non-Destructive Quantitative Phase and Residual Stress Analysis Versus Depth Using Grazing X-Ray Diffraction

2007 ◽  
Vol 130 ◽  
pp. 47-52 ◽  
Author(s):  
S.J. Skrzypek ◽  
M. Goły ◽  
Wiktoria Ratuszek ◽  
Mieczyslaw Kowalski
Keyword(s):  
Residual Stresses ◽  
Phase Analysis ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Ball Bearings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Phase ◽  
Diffraction Geometry ◽  
Non Destructive

The non-destructive structure characterisation of surface layers for various kinds of ball bearings can be a powerful method in surface characterization and in quality control. The ball bearings were made of 100Cr6 steel and they were superfinished and mechanically burnished. An application of classical X-ray diffraction sin2ψ method and classical Bragg-Brentano diffraction geometry in these kinds of surface examinations make some problems in term of X-ray real depth of penetration. An application of methods based on grazing angle X-ray diffraction geometry, made possible to get real value of residual macro-stresses, retained austenite and additionally could be suitable in estimation of their gradient-like distribution versus depth under surface. An application of this geometry to X-ray diffraction phase analysis enabled to get phase contents versus thickness under surface in non-destructive way as well. The results are not infected by gradient-like distribution. The X-ray quantitative phase analysis was used to establish volume fraction of transformed retained austenite. Theoretical calculation of residual macro-stresses due to volume fraction of transformed austenite in ball bearings and following measurements of residual stresses were curried out as well. The mechanical burnishing of ball bearings caused big compressive residual stresses about – 1000 MPa and phase transformation of austenite in thin surface layer. These factors can influence on properties of following exploitation and durability.

Quantitative Phase Analysis of Devonian Shales by Computer Controlled X-Ray Diffraction of Spray Dried Samples

1978 ◽  
Vol 22 ◽  
pp. 181-191 ◽  
Author(s):  
Steven T. Smith ◽  
Robert L. Snyder ◽  
W. E. Brownell
Keyword(s):  
Quantitative Analysis ◽  
Phase Analysis ◽  
Powder Diffraction ◽  
Convenient Method ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intractable Problems ◽  
Computer Controlled ◽  
Spray Dried

Spray drying is shown to be an effective and rapid method for preparing samples for quantitative analysis by x-ray powder diffraction. Previously intractable problems like the simultaneous analysis of multiple phases in orientation prone systems can be carried out. Using this method, and a computer controlled diffractometer, five and six phase analyses of Devonian shales can be accomplished in approximately forty minutes. A rapid and convenient method for using the absorption diffraction technique for x-ray quantitative analysis is described.

Non-destructive phase analysis and residual stresses measurement using grazing angle X-ray diffraction geometry

2006 ◽  
Vol 2006 (suppl_23_2006) ◽  
pp. 375-380 ◽  
Author(s):  
S. J. Skrzypek ◽  
J. Jeleńkowski ◽  
T. Borowski ◽  
W. Ratuszek ◽  
T. Wierzchoń
Keyword(s):  
Residual Stresses ◽  
Phase Analysis ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Geometry ◽  
Non Destructive

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

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