bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Determination of the Acceptable 2θ Error for Non-Ambiguous Identification of Pure Phases wtth Diffrac-at
Authors: Nusinovici J. , Beitelmann D.
Published: March 2019

Search/match of XRD patterns of pure phases can prove useful for verifying the internal consistency of search algorithms. An additional benefit is to check whether there are other materials giving similar powder patterns. If displacements and/or distortions are applied to the input patterns, such trials become a convenient way to estimate the program's tolerance to 2θ errors.

This study has been performed on a set of 70 diffraction patterns from pure phases prepared by the International Centre for Diffraction Data (ICDD) for another purpose. Three search runs were performed on the background corrected full patterns, each time with the default parameters, and on the complete database (59,990 potential candidates): the first run without applying an offset, secondly with +0.20° 2θ offset and thirdly with -0.20°.

The results show that a +/- 0.20° error is still acceptable for non-ambiguous identification of pure phases.
Disposable Heater Strips for High Temperature Powder Diffractometer Furnaces
Authors: King H.W. , Payzant E.A. , Stanley M.B.
Published: March 2019

Commercial resistance heating and thermocouple materials specified for use in air at temperatures up to 1200°C were examined as possible alternatives to Pt-Rh for use as heater strips in high temperature x-ray diffractometer furnaces. Tests in air at 1150°C, showed that Chromel oxidized excessively, Nichrome oxidized moderately, while Kanthal was very slightly oxidized. Nichrome and Kanthal strips were sufficiently ductile to fabricate into strip heaters. The thickness of the Kanthal strip had to be reduced to 0.020 mm to match its resistance to the power and temperature control software of the high temperature diffractometer. Heater strips made from Nichrome proved effective, in terms of resistance to grain growth and surface degradation by adhesive liquid phases, at temperatures up to 1000°C, while Kanthal was effective up to 1150°C. The relatively low costs of these materials also make them viable as disposable heaters for use with chemically reactive or strongly adherent materials.
Residual Stress Measurements in Continuous Fiber Titanium Matrix Composites
Authors: James M. R. , Bourke M. A. , Goldstone J. A. , Lawson A. C.
Published: March 2019

Metal matrix composites develop residual strains after consolidation due to the thermal expansion mismatch between the reinforcement fiber and the matrix. X-ray and neutron diffraction measured values for the longitudinal residual stress in the matrix of three titanium MMCs are reported. For thick composites (> 6 plies) the surface stress measured by x-ray diffraction matches that determined by neutron diffraction and therefore represents the stress in the bulk region consisting of the fibers and matrix. For thin sheet composites, the surface values are lower than in the interior and increase as the outer rows of fibers are approached. While a rationale for this behavior has yet to be developed, accounting for composite thickness is important when using x-ray measured values to validate analytic and finite element calculations of the residual stress state.
Residual Stresses in Aluminum-Mullite (α-Alumina) Composites*
Authors: Balzar Davor , Ledbetter Hassel
Published: March 2019

We studied particle-reinforced 6061-aluminum-alloy composites with particle volume fractions ranging from 0 to 0.25. The mullite particles are approximately spherical and contain embedded α-alumina phase. We obtained lattice parameters of all three phases in the composites and starting materials by using Rietveld refinement of x-ray diffraction patterns. In all three phases stresses are tensile and approximately of the same magnitude, contradicting a requirement for mechanical equilibrium. Stresses increase with both increasing particle size and volume fraction. Measurements of extracted-from-composites particles showed no evidence of a possible chemical reaction at the matrix-particle interface. The matrix is [111] and [100] textured, but measurements of elastic constants reveal only small anisotropy. Thus, explanation of the mechanical-equilibrium violation remains uncertain.
Neutron Diffraction Study of the Pseudo-Macro Residual Stresses in ZrO2(CeO2)/Al2O3 Ceramic Composites
Authors: Wang Xun-Li , Hubbard C. R. , Alexander K. B. , Becher P. F. , Fernandez-Baca J. A. , Spooner S.
Published: March 2019

Neutron powder diffraction techniques have been used to characterize the pseudo-macro (PM) residual stresses in ZrO2(CeO2)/Al2O3 ceramic composites as a function of ZrO2(CeO2) volume fraction and fabrication procedures. The diffraction data were analyzed using the Rietveld structure refinement technique. From the refinement, we found that the CeO2 stabilized tetragonal ZrO2 particles were in tension and the Al2O3 matrix was in compression. Different sintering time had little impact on the PM stresses. On the other hand, the magnitude of the PM stresses in both ZrO2 and Al2O3 decreased linearly with the increase of their volume fractions.
X-Ray Residual Stress Measurement on Stress Corrosion Fracture Surfaces
Authors: Tsuda Masaaki , Hirose Yukio , Yajima Zenjiro , Tanaka Keisuke
Published: March 2019

X-ray fractography is a new method utilizing the X-ray diffraction technique to observe the fracture surface for the analysis of the micromechanisms and mechanics of fracture. X-ray residual stress has been confirmed to be a particularly useful parameter when studying the fracture surfaces of high strength steels. The method has been applied to the fracture surface of fracture toughness and fatigue specimens.
X-Ray Fractography Evaluation of the Plastic Zones of Dynamic Fracture
Authors: Matsui Kazuyuki , Nakada Osamu , Hirose Yukio , Tanaka Keisuke
Published: March 2019

To evaluate the plastic zones of dynamic fracture, instrumented Charpy impact tests of high carbon bearing steels are conducted. The amount of plastic zone size left on the fracture surface is evaluated from the X-ray diffraction profiles. An analysis is presented of the relationship between the X-ray diffraction profiles and fracture mechanics parameters. The results are discussed in correlations between dynamic stress intensity factor and absorbed energy values. A good correlation exists between the plastic zone size and the dynamic stress intensity factor.

The fraction of retained austenite is determined from X-ray diffraction profiles at surfaces of fractures and also beneath the surfaces of fractures.

It shows the work hardening is introduced by the strain energy in the plastic zones. The values of the proportionality constant, α, determined for various kinds of dynamic fracture are related to half-value breadth by the function

where B0and BFare average of half-value breadth which are given by core of material and plastic zone of dynamic fracture.
The Ladell Diffractometer: Geometry and Applications
Authors: Greenberg Berton
Published: March 2019

The Ladell x-ray diffractometer (LD) is designed to study “practical” polycrystalline materials. These are materials which exhibit some combination of texture, strain, and large grain size, or are inhomogeneous or anisotropic in other ways. LD features which make this possible are: the ability to study crystal planes inclined to the sample surface; a versatile reflection geometry; high 2θ resolution via a focusing geometry; a large irradiated sample area (up to 1.5 cm2) for improved intensity and sampling statistics; the ability to examine different sample areas to test for homogeneity; and the use of one sample with no instrument reconfiguration. Scans and/or applications are described that measure texture, strain, twinning, improve quantitative phase analysis, and eliminate substrate scattering.

The LD makes use of five independent computer controlled motions. These enable one to study a large fraction of that part of reciprocal space which is accessible by reflection. Instrument geometry and scans are described in terms of α, θ and reciprocal space diagrams. The effect of specimen displacement on peak position is described as are the effects of a number of geometrical factors on integrated intensity.
Use of a Two-Dimensional, Position Sensitive Detector for Collecting Pole Figures
Authors: Smith Kingsley L. , Ortega Richard B.
Published: March 2019

Conventional pole figure instruments consist of a scintillation detector mounted on a 4-circle goniometer operating under computer control. A few instruments make use of a linear PSD detector, which allows collecting data for multiple pole figures sinmltaneously. A PSD does not reduce the required data collection time for the primary pole figure; however, it does save time by eliminating the need to recollect multiple pole figure data. By using a 2D “area” detector, one can simultaneously collect multiple pole figures and reduce the data collection time for the primary pole figure, such an area detector pole figure processing package, GADDS v2, was developed at Siemens and will be discussed.
The D5000 HR System: Increased Resolution for the Multipurpose Siemens X-Ray Diffractometer
Authors: Brügemann L.
Published: March 2019

Lately available X-ray optics and 4-axis sample cradles increased the versatility of the Siemens D5000 diffractometer to high resolution applications. The possibilities of the D5000 HR hardware setup are illustrated by presenting diffraction measurements on systems relevant to semiconductor and thin film technology. Well known theoretical approaches are used for the software supported interpretation of the data.
Synchrotron and Laboratory Studies Utilizing a New Powder Diffraction Technique
Authors: Knapp G. S. , Beno M. A. , Jennings G. , Engbretson M. , Ramanathan M.
Published: March 2019

We have developed a new type of powder diffractometer. The diffractometer has the potential of both high count rates and very high resolution when used at a synchrotron source. The laboratory based instrument can achieve an order of magnitude improvement in count rate over existing methods with proper optics. The method uses a focusing diffracted beam monochromator in combination with a multichannel detector. The incident x-rays fall on a flat plate or capillary sample and are intercepted by a bent focusing monochromator which has the focus of the bend at the sample surface. The powder diffraction lines emerging from the bent crystal monochromator are detected by a linear or 2-dimensional detector. This allows us to eliminate the background from fluorescence or other scattering and to take data over a range of 3° to 4° instead of one angle at a time thereby providing a large improvement over conventional diffractometers.
High Resolution X-ray Diffraction for the Characterization of Semiconducting Materials
Authors: Tanner B. K.
Published: March 2019

Use of a reference crystal to condition the beam in the double-axis diffractometer permits the Bragg peak width to be reduced to the correlation of the two crystal reflecting ranges. Some recent applications of double axis diffractometry to the study of heteroepitaxial layers are discussed. The advantages of multiple reflections for beam conditioning and the four reflection DuMond monochromator are examined. Glancing incidence and exit diffractometry permits the study of very thin layers, down to a few tens of nanometres in thickness and both synchrotron radiation and skew reflections can be used to tune the glancing angle close to the critical angle. Recent applications of triple-axis diffraction, where an analyzer crystal is used after the specimen, to the study of very thin single epitaxial layers and multiquantum well structures are reviewed.
Deformation, Recovery and Stress Corrosion Cracking of Nickel-Base Alloy 600 by X-ray Rocking-Curve Measurements
Authors: Lo Chi Fung , Feng Gajiang , Mayo William E. , Weissmann Sigmund
Published: March 2019

The aim of this investigation was the establishment of a quantitative link between micro and macrodeformation and kinetic recovery of nickel-base Alloy 600 as well as the early detection of microcracks in this alloy when exposed to stress corrosion. To reach these objectives, X-ray rocking-curve measurements were carried out using the method known by its acronym CARCA (computer-aided rocking-curve analysis). Supported by transmission electron microscopy, a calibration curve was established relating dislocation density, X-ray rocking-curve halfwidth and strain. Applying CARCA, deformation levels and work-hardening characteristics of the alloys were measured by quantitative characterization of the induced defect structure. By correlating the analysis of the defect structure to the kinetic recovery of the alloys, including determination of the activation energies, it was possible to infer from the thermal stability of the alloys the dislocation obstacles responsible for hardening at different strain levels. It was shown that the recovery of the alloys was conditioned by their low stackingfault energy and that it depended on the strain level. Rapid recovery associated with grain boundary diffusion occurred at very small plastic strains up to about 0.7% with measured activation energies of recovery of about 25.6 Kcal/mol. At higher strains bulk diffusion was necessary to overcome the obstacles by dislocation climb with Q — 67 kcal/mol, The CARCA method proved itself to be a valuable research tool for assessing quantitatively the defect density and the mechanically and thermally induced changes. Relaxation effects, recorded by CARCA in the apex region of stressed C-rings exposed to a caustic medium, may open a path for early nondestructive detection of microcracks in stress-corrosion cracking.
X-ray Characterisation of Residual Surface Strains after Polishing of Silicon Wafers
Authors: Hart Linda , Bowen D. Keith , Fisher Graham R.
Published: March 2019

Detailed x-ray double-axis rocking-curve analysis has been made of a series of silicon wafers, polished using various colloidal silicas with a number of different conditions. Significant differences, attributable to the polishing conditions, were observed in the tails of the rocking curves, using a four-reflection, non-dispersive beam conditioner. These have been compared with theoretical simulations in order to deduce the strain profile near the surface.
X-ray Line Broadening Analysis of Tl-Superconducting Films
Authors: Eatough M. O. , Ginley D. S. , Morosin B.
Published: March 2019

Superconducting thin films (0.3-0.7μm) in the TI-Ca-Ba-Cu-0 system have been prepared on various single crystal substrates by sequential electron beam evaporation followed by appropriate sintering and annealing. Oxygen-annealed films show Tc as high as 110K and critical current densities to 600,000 A/cm2. X-ray diffraction analyses of these films show predominantly the Tl2Ca2Ba2Cu2O10 phase (c-parameter near 36Å), but some also contain up to 50 at% of the Tl2CaBa2Cu2O8 phase (c-parameter near 30Å). The complete absence of hkl reflections other than 00I demonstrates the highly oriented nature of the films as well as the absence of other Tl phases. The diffraction peaks are noticeably broader for the 36Å phase than for the 30Å phase. For a 0.7μm film such broadening is consistent with coherent sizes along the c-axis of 1200 - 1400Å and 500Å, respectively, for the 30Å and 36Å phases, and of strain values near 1.4-1.8 x 10-3 for both phases.
Application of Multi-Layer Thin Film Analysis by X-ray Spectrometry Using the Fundamental Parameter Method
Authors: Kataoka Y. , Arai T.
Published: March 2019

The fundamental parameter method for x-ray spectrometry has been used most commonly for bulk samples, because it permits an analysis utilizing a minimum number of standards, even for samples with complicated matrices. The need for the analysis of thin film materials, which includes multi-layer films, has been increasing in recent years along with the rapid progress of high technologies. However, there have been few reports that deal with the application of fundamental parameter methods to multi-layer thin films. There may be two situations in the analysis of thin films. In routine analysis of quality control applications, they usually require precise analysis. Fortunately, it is possible to prepare well characterized standards similar to the unknowns.
The Optimization of Step Size While Collecting a Digitized Diffraction Pattern at a Constant Total Scan Time
Authors: Burleson John R.
Published: March 2019

Given a limited amount of time for data collection, what parameters do you select to generate the highest quality x-ray diffraction pattern from an automated diffractometer? This paper addresses the major topic of diffractometer step size or its equivalent, chopper size, for instruments running in the continuous scanning mode. In general, step size and chopper size will be interchanged freely. A minor topic intertwined into the discussion will be the receiver slit width.
Residual Stress Distribution of Ceramic-Metal Joint
Authors: Kurita Masanori , Sato Makoto , Ihara Ikuo , Saito Akira
Published: March 2019

Ceramics are sometimes bonded to ductile metals in order to make up for their brittle behavior for industrial use. The residual stress will be induced in ceramics bonded to metals at high temeprature, and it has a strong influence on the strength of ceramic-metal joints. A silicon nitride plate was bonded to a carbon steel plate by brazing to a copper sheet sandwiched between the two materials. The residual stress distribution of the joint specimen was determined by x-ray diffraction using the Gaussian curve method. The measured residual stress distribution almost agreed with that calculated by the three-dimensional thermoelastoplastic stress analysis using FEM, but differed remarkably from that calculated by the two-dimensional stress analysis. This is because a stress concentration occurs at the ceramic-metal interface and the stress distributes three - dimensionally. The stress σx in the axial direction on the surface of the specimen takes maximum values at the center and the edge of the interface.
The Comparison of Several Standard Materials and Techniques for the Warren-Averbach Determination of Microstructure Characteristics of Calcium Hydroxide Sorbent Materials
Authors: Briden Frank E.
Published: March 2019

The Air and Energy Engineering Research Laboratory (AEERL) has been investigating the injection of dry calcium hydroxide into combustion streams for the removal of sulfur oxides. It has been known, for some time, that the reactivity of Ca(OH)2 with sulfur oxides varies over a wide range for different batches of calcium hydroxide. The reactivity is a critical factor in the economics of the process. Because of this it is desirable to have a method to predict the reactivity of calcium hydroxide batches. The reactivity can be affected by many factors including the origin of the calcium carbonate mineral from which the hydroxide is produced, the production conditions, and the concentration of additives used for reactivity enhancement. It has been theorized that all of the preceding contribute to such physical characteristics as surface area, particle size, and porosity. The examination of these physical characteristics has provided the basis for understanding the reaction processes but has net provided all the factors necessary to correlate intrinsic sorbent characteristics with reactivity.
The Determination of Quartz in Perlite by X-ray Diffraction
Authors: Hamilton R. D. , Peletis N. G.
Published: March 2019

IARC's designation of crystalline silica as a “probable carcinogen” triggered the requirement to label products containing greater than 0.1 % crystalline silica. For perlite and other materials which may contain crystalline silica in levels close to 0.1% an accurate determination is critical from both legal and marketing considerations.

Existing analytical techniques for the determination of crystalline silica at levels of less than 1.0% were found to be inadequate to meet the new requirements. An improved technique based on x-ray diffraction has been developed specifically to analyze perlite for crystalline silica, which occurs largely in the form of quartz, at the 0.1%. level. The technique employs long counting times and improved sample preparation and mounting to increase both precision and accuracy, and to lower the detection limit to less than 0.1%.

The technique was tested on a large number of samples from a variety of sources and proven to give excellent results for all types of expanded perlites and perlite ores. The procedures developed are applicable to a wide variety of materials in addition to perlite.
A Versatile Fundamental Alphas Program for Use with Either Tube or Secondary Target Excitation
Authors: Feng L. , Pella P. A. , Cross B. J.
Published: March 2019

During this decade, several influence-coefficient algorithms have been published which utilize fundamental parameter equations to correct interelement effects in bulk samples. The Comprehensive Algorithm of Lachance (COLA) is one such algorithm and is used in the program NBSGSC(l). Another COLA-based computer program called FLY-FPM has been developed in China by one of the authors (L. Feng). Using FLY-FPM as a starting point, we developed a new COLA-based program as part of a Cooperative Research Agreement with Kevex Instruments. This program was designed for use with x-ray spectrometers that employ both tube and secondary targets for excitation. For direct tube excitation, the NIST tube spectral distribution algorithm is used in this program (2). For secondary target excitation, the radiation is usually treated as being monochromatic, and fundamental parameter expressions are formulated with this in mind.
Absorption Corrections via Backscattered Radiation in Polychromatic Excitation Energy-Dispersive X-ray Fluorescence Spectrometry
Authors: Araüjo F. , He F. , Van Espen P. , Van Grieken R.
Published: March 2019

The incoherently and coherently scattered X-ray intensities with the corresponding scatter factors have been used previously define in a sample matrix the light elements (Z<12) constituents which can not be a s sessed via their fluorescent radiation in conventional XRF. Recently, a more complete sample definition has been achieved based on the backscattered X-rays, by using two excitation modes. However, all quantitative EDXRF methods, based on the scattered radiation from the sample relied hitherto uniquely on the use of monochromatic excitation radiation.
SPC: What is It and Why Should You Use It in Your Xray Analytical Laboratory?
Authors: DeGroot P. B.
Published: March 2019

Statistical Process Control (SPC) methods have become extremely popular in quality control and process improvement in the manufacturing environment, first in Japan and more recently in the U.S. They are gradually being introduced into the research and development setting as well, where they offer some advantages over more traditional statistical approaches. The greatest advantage of the SPC approach is that it ensures that the statistical description generated is valid, i.e., that the data on which it is based incorporate only random error. This is verified both initially and on a continuing basis. This means that the results provide valid predictions of future performance, not just a description of an historical set of replicate samples. SPC statistical evaluations of analytical results and instrument performance require only simple calculations and are easily applied in a consistent, valid manner by statistically unsophisticated analysts. Besides the numerical statistical analysis tools, the SPC approach provides other problem-solving techniques for improvement of the entire analysis process. These aspects of the SPC approach will be described and illustrated with examples from our x-ray fluorescence analysis laboratory.
X-ray Capillary Microbeam Spectrometer
Authors: Larsson S. , Engstrom P. , Rindby A. , Stocklassa B.
Published: March 2019

By utilizing the total reflecting properties of x-rays inside glass capillary tubes, intensive fine- or microbeams of x-rays can be attained. By using a conventional x-ray tube in combination with capillary technique, microbeams with a diameter of a few μm and with an intensity sufficient for trace elements, analyses have been achieved. By moving the sample, lineand areascan can be performed and trace element information can be directly superimposed on a micrograph from a built-in optical microscope.

The background of the capillary technique is reviewed and an EDXRF microbeam spectrometer for trace elements is described. Examples of applications for the microbeam spectrometer are given.
Application of PIXE Method for Environmental Protection in Poland
Authors: Zoltowski T. , Ratynski W. , Jaskola M. , Parus J. , Wawrzonek L.
Published: March 2019

Specific problems of environmental protection in Central Europe and dense industrialization in Poland that is powered by traditional power plants and having developed heavy industry, have resulted in a need for a special environmental protection policy. Reliable methods are needed to analyze low concentrations of trace elements in pollutants existing in atmospheres, precipitates, ground waters and soils. A knowledge of trace-elements concentration can help in setting industrial limits for emission, permanent control of emission perturbations and finally epidemiological studies. During recent years, methods based on the x-ray fluorescence phenomenon were being widely developed in Poland. Now due to the development of cyclotrons, proton-induced x-ray emission appears to be very useful for pollutant control.
X-Ray Diffraction Using Synchrotron Radiation - A Catalysis Perspective
Authors: Newsam J. M. , King H. E. , Liang K. S.
Published: March 2019

Synchrotron X-radiation provides unique opportunities for diffraction experiments and, therefore, for extending our understanding of the structure - property interplay in catalyst systems. The present status of opportunities and applications of synchrotron X-ray diffraction techniques in the structural chemistry and catalysis science areas is overviewed, and illustrated by selected recent results.
The Determination of Rare Earth Elements in Geological Samples by XRF Using the Proportional Factor Method
Authors: Yuanpan Chen
Published: March 2019

This paper describes the principle, method and application of the proportional factor method for the determination of rare earth elements (REE) in geological samples by XRF, The analytical results of this method are compared with REE recommended values in geological standards, and good agreement was observed. Five of the REE (Pr, Tb, Ho, Tm and Lu) have also been determined by interpolation from chondrite-normalized plots, and more satisfactory results were obtained.
The Homogeneity of Fe, Sr and Zr in SL-3/Lake Sediment Standard Reference Material by Radioisotope Induced X-ray Emission
Authors: LaBrecque J. J. , Rosales P. A.
Published: March 2019

Following an international interlaboratory comparison study of SL-3 Lake Sediment sample, the results showed a large range of values for the iron concentration (0.538 to 1.270% Fe) with an overall standard deviation of 18 percent from 38 accepted laboratory averages, see Figure 1 (1).
Impurity Analysis of Silicon Wafers by Total Reflection X-ray Fluorescence Analysis
Authors: Nomura Sigeaki , Nishihagi Kazuo , Tauiguchi Kazuo
Published: March 2019

High purity of silicon wafers is demanded by the high performance and highly integrated IC and LSI semiconductors. Impurities on, or in, the silicon wafer have a big influence on the characteristics of the semiconductor as a final product. Usually, these impurities are introduced by water during washing, by bad handling, or by reagents and processes.

Typical influences of these impurities are shown in Table 1. These elements are present at too small concentration to he detected by ordinary analytical methods (except for oxygen). Usually, XPS , AES, NAA, SIMS, ICPAES, ICP-MS and AAS are used for trace analysis.
Low Level Iodine Detection by TXRF Spectrometry
Authors: Hegedüs F. , Winkler P.
Published: March 2019

A special measurement technique has been developed to measure very low level iodine concentrations. The gas and water samples to be analysed are taken from the POSEIDON facility at PSI where retention of iodine in water pools in conjunction with light water reactor safety analysis is under investigation. The amount of iodine was measured by means of a Total Reflectance X-Ray Spectrometer (TXRF).
X-ray Diffraction of Thin Oxide Films on Soldered Module Pins
Authors: Adi T. Paul , Stehmeyer H. F.
Published: March 2019

The presence of metal oxide films from wave solder baths on timed module pins are partly responsible for non-wet problems in subsequent soldering steps. The cylindrical geometry of the pins lends itself to the characterization of thin oxide films by using the highly sensitive Debye-Scherrer camera method. As confirmed by Electron Hicroprobe Analysis (EMA), pins containing thin oxide films were used to obtain the diffraction patterns. A software program was developed that subtracts the diffraction angles of an oxids-free control pin from the pattern of the contaminated pin, and tabulates the residual d-spacing (interplanar distance) of the contaminant film.
Residual Stress Measurement of Silicon Nitride and Silicon Carbide by X-Ray Diffraction Using Gaussian Curve Method
Authors: Kurita Masanori , Ihara Ikuo , Ono Nobuyuki
Published: March 2019

The residual stress induced by grinding or some thermal treatment has a large effect on the strength of ceramics. The X-ray technique can be used to nondestructively measure the residual stress in small areas on the surface of polycrystalline materials. The X-ray stress measurement is based on. the continuum mechanics for macroscopically isotropic polycrystalline materials. In this method, the stress value is calculated selectively from strains of a particular diffraction plane in the grains which are favorably oriented for the diffraction. In general, however, the elastic constants of a single crystal depend on the plane of the lattice, since a single crystal is anisotropic, The behavior of the deformation of individual crystals in the aggregate of polycrystalline materials under applied stress has not yet been solved successfully. Therefore, the stress constant and elastic constants for a particular diffracting plane should be determined experimentally in order to determine the residual stress accurately by X-ray diffraction.
Residual Stresses in Al2O3/SiC (Whisker) Composites Containing Interfacial Carbon Films
Authors: Abuhasan Alias , Predecki Paul K.
Published: March 2019

Residual strains and stresses were measured in hot-pressed α-Al2O3 composites containing 25 wt% β (cubic) SiC whiskers with and without a 50-100Å thick carbon coating. X-ray diffraction methods were used including the separation of macrostresses from the microstresses in the -Al2O3 and SiC phases by the method of Noyan and Cohen. The presence of the carbon coating on the whiskers reduced the magnitude of the residual microstresses in the whiskers by ˜13% and in the matrix by ˜10%. The measured residual stresses in the whiskers and the reduction due to the carbon film were in good agreement with calculations from recent models proposed by Hsueh, Becher and Angelini, and by Li and Bradt.
Parameters Affecting X-Ray Microfluorescence (XRMF) Analysis
Authors: Nichols Monte C. , Boehme Dale R. , Ryon Richard W. , Wherry David , Cross Brian , Aden Gary
Published: March 2019

X-ray Microfluorescence (XRMF) analysis uses a finely collimated beam of X-rays to excite fluorescent radiation in a sample (Nichols & Ryon 1986). Characteristic fluorescent radiation emanating from the small interaction volume element is acquired using an energy dispersive detector placed in close proximity to the sample. The signal from the detector is processed using a computer-based multi-channel analyzer.

XRMF imaging is accomplished by translating the sample through the small X-ray beam in a step or continuous raster mode. As the sample is translated, a pixel by pixel X-ray intensity image is formed for each chemical element in the sample. The resulting digitized image information for each element is stored for subsequent processing and/or display. The images, in the form of elemental maps representing identical areas, may be displayed and color coded by element and/or intensity and then overlayed for spatial correlation.

The present study of parameters affecting the performance of an X-ray microfluorescence system has shown how such systems use X-ray beams with effective spot sizes less than 100 micrometers to bridge the gap in analytical capabilities between predominately surface micro analytical techniques such as SEM/EDX and bulk analytical methods such as standard XRF analysis. The combination of XRMF spectroscopy with digital imaging allows chemical information to be obtained and mapped from surface layers as well as from layers or structures beneath the sample surface. Simultaneously, it provides valuable high resolution chemical information in a readily interpreted visual form which displays the homogeneity within a given layer or structure. XRMF systems retain the advantages of minimal sample preparation, non-destructive analysis and high sensitivity inherent to XRF methods.
Imaging Techniques for X-Ray Fluorescence and X-Ray Diffraction
Authors: Gurker N.
Published: March 2019

Electron induced X-ray mapping together with modern SEM/EDX analysis systems has reached a high level of perfection due to established methods of beam deflection and focusing and today's standard in energy dispersive X-ray detection and data processing. X-ray analysis of specimens based on X-ray excitation (XRF/XRD) is routinely performed on comparatively large specimen areas without conserved spatial information. XRF-/XRD-imaging capabilities are not yet commonly available on standard spectrometers, since both suitable X-ray optical elements are missing and there is a large intensity loss due to the necessary primary beam collimation.
Robotic Automation Applied to X-Ray Fluorescence Analysis
Authors: Cross J. B. , Jones R. D.
Published: March 2019

X-Ray Fluorescence (XRF) Analysis is an established analytical technique, widely used in industry and research laboratories for accurate, reproducible, and timely analysis of liquid (aqueous and non-aqueous) and solid samples. Modern X-ray spectrometers are of many types, ranging from inexpensive, simple systems for single element analysis to complex, expensive, automated systems capable of providing thousands of determinations per week. Automated data handling is now relatively commonplace, as are sample changers and matrix correction techniques. For proper application of the technique, it is still necessary to prepare the sample in a suitable manner and present it to the spectrometer so that quantitative information can be obtained. This step, sample preparation, is the most labor intensive portion of the analysis.
X-Ray Fluorescence Analysis of Geological Materials Using Rousseau's Fundamental Algorithm
Authors: Johnson R. G.
Published: March 2019

The analysis of many types of geological samples by X- ray fluorescence (XRF) spectroscopy has become routine. For example, the analysis of major elements in silicate rocks is not a problem because of the large number of standard reference materials available, and because of the benefits of the fusion preparation. Even simple linear regression analysis provides accurate results when standards and samples are similar.
Monte Carlo Simulation of the X-Ray Fluorescence Spectra from Multielement Homogeneous and Heterogeneous Samples
Authors: Yacout A. M. , Gardner R. P. , Verghese K.
Published: March 2019

A Monte Carlo model that predicts the entire photon, spectrum for energy-dispersive X-ray fluorescence (EDXRF) analyzers excited by radio-isotope sources from multielement homogeneous samples is developed and demonstrated. The components of the photon spectrum include: (1) the and Kα and Kβ characteristic primary, secondary and tertiary X rays from both the unscattered and scattered source photons, (2) the characteristic X rays excited by other characteristic X rays that have been scattered, and (3) the scattered source photons from single, double, and multiple scatters in the sample.

The computer code NCSMCXF based on this model has been developed. It is capable of handling up to 20 elements per sample and provides a detailed account of the intensities of the X rays and backscattered source photons per unit source decay as well as a summary of the relative intensities from all elements present in the sample. Cubic splines are used within the code for photoelectric and total scattering cross sections and two-variable cubic splines for angular coherent and incoherent scattering distributions for efficiency in both computation time and storage. The code also provides the pulse-height spectrum of the sample by using the appropriate Si(Li) detector response function. The Monte Carlo predictions for benchmark experimental results on two alloy samples of known composition indicate that the model is very accurate. This approach is capable of replacing most of the experimental work presently required in EDXRF quantitative analysis.

A previous Monte Carlo model that uses the simple assumption of spherical homogeneous particles to approximate sample heterogeneities has been modified to improve the computer execution time requirements for the heterogeneous sample case. A new technique for photon tracking in this medium is used and reduces the computation time requirement by half.
A Quantitative Texture Analysis of Pluri-Crystals by Texture Goniometry
Authors: Vadon A. , Heizmann J. J. , C. Laruelle
Published: March 2019

To understand how a material evolves - its crystal growth, topotaxy, twinning, phase transformation, plastic deformation, microstress, etc. - it is important to know the crystal orientations, either between them or in respect to the sample.

The crystal texture of the material is quantified by the Orientation Distribution Function (O.D.F.). This function represents the part of the material volume having a given orientation. To compute this O.D.F, we must first measure one or several complete or incomplete pole figures and then analyse them either with Roe-Bunge's harmonic method or with Vadon, Ruer, Baro's vector method. In the case of a very sharp texture, the results obtained with the harmonic method are not good because developing a DIRAC function in spherical harmonics requires a high rank, hence a large number of pole figures. On the contrary, with the vector method, the results are good since discretizing amounts to developing on a step-function basis.
The Effects of Extinction on X-Ray Powder Diffraction Intensities
Authors: Cline Janies P. , Snyder Robert L.
Published: March 2019

Several factors have long been known to affect the intensity measurements of X-ray powder diffraction. The characterization of these effects has been impeded by difficulties in their isolation and the statistical nature of the data in which they manifest themselves. The most celebrated, and most detrimental, of the these effects is that of preferred orientation. This error can be eliminated with the spherical agglomeration of the sample (1). The spray drying process offers this result and is considered to have the broadest range of applicability to materials encountered by the powder diffractionist.
Analysis of Surface Layers and Thin Films by Low Incident Angle X-Ray Diffraction
Authors: Iyengar S. S. , Santana M. W. , Windischmann H. , Engler P.
Published: March 2019

Due to the current high interest in characterizing epitaxially deposited thin films required by the electronics industry as well as the increased attention in elucidating reactions between solid surfaces and the environment (e.g., corrosion), investigators have increased their efforts in developing X-ray procedures for analyzing films and surfaces less than 2 μm thick. For example, an entire session of the 1985 Denver Conference on Applications of X-ray Analysis was devoted to this subject and an excellent review of X-ray diffraction techniques for characterizing thin films was recently published by Segmuller (1). Specific techniques include grazing incidence diffraction (2, 3), double crystal diffraction (3), and the use of the Seemann-Bohlin focusing geometry (4, 5).
X-Ray Fractography of Fracture Surface of Alumina Ceramics
Authors: Mishima Tadao , Nanayama Yukio , Hirose Yukio , Tanaka Keisuke
Published: March 2019

X-ray diffraction observation of fracture surface yields useful information to analyze the cause of failure accidents of engineering structures. This experimental technique, named X-ray fractography, has been developed especially in Japan. The relationship between X-ray parameters and fracture mechanics parameters plays a key role in
determinating the mechanical condition of fracture.
Dosimetry of X-Ray Beams: The Measure of The Problem
Authors: de Castro Ted
Published: March 2019

While x-ray dosimetry is most definitely a "Measure of the Problem" in Analytical X-Ray Safety, there are additional factors which further enlarge the problem and are equally major considerations which must be taken into account when deciding upon the degree of action appropriate to prevent this problem.

Certainly, some idea of the nature of the typical levels of natural and man-made sources of radiation which surround us daily is useful to give us a perspective on the magnitude of radiation levels from analytical x-ray equipment. It is also important to know what levels of radiation exposure are considered unacceptable, either by regulatory limits or because of the potential for physiological damage.

The consequences of an exposure to radiation from analytical x-ray machines will often go beyond a report of an overexposure and investigation, or painful and lasting physiological damage. There are times when the matter will come before our courts in order to fix responsibility and decide compensation for injuries suffered.
Microstructural Characterization of Thin Polycrystalline Films by X-Ray Diffraction
Authors: Wagner C.N.J. , Boldrick M.S. , Keller L.
Published: March 2019

The Fourier analysis of the broadened profiles in a powder pattern allows the determination of the effective particle or domain size and the microstrains within each domain in polycrystalline materials. In order to apply this method to the diffraction patterns of thin films and coatings, deposited on crystalline or amorphous substrates, special diffraction techniques must be employed for the registration of the relatively weak intensities. The fitting of the experimental profiles to pseudo-Voigt functions permits the recovery of the peak tails and a precise determination of the background. The positions of the peak maxima or centroids yield information about any compositional variations, and about the occurrence of stacking faults and residual stresses in thin films and coatings.
Problems and Solutions in Quantitative Analysis of Complex Mixtures by X-Ray Powder Diffraction
Authors: Bish David L. , Chipera Steve J.
Published: March 2019

In spite of the wide availability of automated diffractometers and advanced data reduction software, numerous traditional problems still exist that make highly precise and accurate quantitative analyses of complex mixtures difficult. The problems include particle statistics, primary extinction, microabsorption, preferred orientation, overlapping and broad reflections, variation in standard data with composition, availability of pure standards, and detection of amorphous and trace phases. Our analyses of rocks use the matrix flushing method on < 5μm particle-size material mixed with a 1.0-μm corundum internal standard to minimize the first four effects. Integrated intensities are used, and we employ several peaks from each phase whenever possible. We overcame overlap problems through iterative calculations using integral, multiple peaks or with profile refinement. Use of observed and calculated diffraction patterns for every phase enables us to predict the effects of composition and preferred orientation on RIRs. This allows us to correct for these effects if reference intensity ratios (RIRs) are known as a function of composition and orientation. Detection of amorphous phases is a significant problem, and standard mixtures reveal that amounts of amorphous components below 30% are difficult to detect. The poor detection limit and the nature of the diffraction band from amorphous phases make internal standard or spiking methods the best approach for analyzing samples containing amorphous materials. The Rietveld method of quantitative analysis has the potential to minimize all of the above problems. This method requires a knowledge of the crystal structures of all component crystalline phases, but no calibration data are necessary, structural and cell parameters can be varied during the refinement process, so that compositional effects can be accommodated and precise cell parameters can be obtained for every phase. Since this method fits the entire diffraction pattern and explicitly uses all reflections from every phase, complex, overlapped patterns can be easily analysed. In addition, this method presents the opportunity to correct for preferred orientation and microabsorption during data analysis.
Measuring Graphitic Carbon and Crystalline Minerals in Coals and Bottom Ashes
Authors: Wertz David L. , Collins Leo W. , Froelicher Franz
Published: March 2019

The use of coal, as either a primary energy source or as a source of feedstock chemicals, has been complicated by the noxious and toxic chemical species formed in its gaseous effluents and also by the huge quantities of ash vhich result from its processing. Both the noxious gases and the ash have been the subjects of Federal legislations.

X-ray powder patterns (XRPP), composed of atom-pair and self x~ray scattering and the diffraction produced by crystalline phases, have long been used to investigate coals and particularly their combustion ashes (1-3). Over twenty different crystalline phases have recently been reported to exist in certain lignite fly ash (3). Analysis of the crystalline phases has typically been emphasized in previous papers involving coals and ashes, but the amorphous scattering has been given little treatment.
X-Ray Study of the BaO-Y2O3-CuOxSystem
Authors: Wong-Ng W. , Roth R. S. , Beech F. , Davis K. L.
Published: March 2019

Ten compounds are found in the Ba0-Y203-CuOxsystem. High temperature (≈950-1000°C) phases identified as Ba4Y2O7, Ba2Y2O5, Ba3Y4O9, BaY2O4, Y2Cu2O5, BaCuO2+x, Ba3YCu2OZBaY2Cu05and BazYCu306+xare formed in this temperature range. In addition, a new compound with composition of 2BaO:CuO, which possibly has a melting point below 950°C, was prepared at 850°C. A summary o£ the crystallographic data of these 10 phases is given. In particular, results of x-ray studies pertaining to four compounds, BazYCu306+x, which is currently the most promising high To' superconductor material, Ba2Cu03, BaY2Cu05, and Ba3YCu20Zare reviewed.