bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative XRD Analysis by Partial Least Squares Application in a Commercial Product
Authors: Mateos Arthur G.
Published: March 2019

A new approach to quantitative XRD by Partial Least Squares (PLS) used region(s) or the entirety of the diffraction pattern of calibration standards (also called a training set) in the model. The basic concept of this approach states that the information in many observed variables, expressed as matrix I = (i1, i2 … , ik,) is concentrated onto a few underlying latent variables, called factors, by the process of data compression. In XRD, the data points of the diffraction pattern are compressed to few factors T, computed according to their ability to explain the variation in the diffraction pattern or matrix I. The procedure incorporates into the model that part of I that is correlated to C concentrations. Data compression preserves the redundancy between variables due to collinearity and stabilizies the predictions against noise in I. The resulting calibration model allows for detection of outliers. Another important effect of data reduction is the ability to analyze muticomponent systems even when lines of the components are overlapped, Examples of quantitative analysis by PLS are demonstrated in the analysis of a commercial product.
Application of Synchrotron and Flash X-Ray Topography to Improved Processing of Electronic Materials
Authors: Winter J.M. , Green R.E. , Green K.A.
Published: March 2019

White beam transmission topography was used to image defect structures in gallium arsenide single crystal substrates representative of those used for microwave integrated circuit fabrication. A scanning topographic camera was developed for Beamline X-19C at the National Synchrotron Light Source. Acquiring film topographs within a particular range of scan rates and x-ray fluxes was found to produce distorted images. The distortions were shown to be thermoelastic, arising from inhomogeneous deposition of thermal energy through the absorption of residual x-rays. The problem could be circumvented using faster scans with some sacrifice in spatial resolution. Real time electrooptic topographs were recorded using x-ray fluxes about one percent of those used for the film topographs. The potential for reducing the flux requirement to even lower levels which would be accessible to flash x-ray generators is considered.
Correcting Effect of Preferred Orientation in Transparent Samples
Authors: Järvinen Matti , Laakkonen Marja-Liisa , Paakkari Timo
Published: March 2019

Accurate diffraction intensity measurement from powder samples with a modern automatic x-ray diffractometer is nowadays a routine work. Most of the difficulties are caused because the samples are not the ideal ones. Especially, the effect of preferred orientation (or texture) may drastically distort the ratios of intensities in the collected data. To diminish these effects more careful preparation of the samples is needed. This is, however, often tedious and its success is not certain.
Calibrating for X-Ray Diffraction Analysis of Trace Quartz
Authors: Renault Jacques , McKee Chris , Barker James
Published: March 2019

Trace analysis of quartz at the <0.1 wt% level can be routinely accomplished by x-ray diffraction using rotating pressed-powder briquettes and a peak deconvolution strategy due to Wiedemann, et al. (1937a, b) which permits reproducible determination of background and enhances peak resolution without changing the integrated intensity.

Four calibration methods were tested: (1) calibration with perlites microscopically analyzed by Hamilton and Peletls (1988), (2) with artificial mixtures of quartz and glass, (3) with chemical analysis and massbalance calculation of quartz in glass mixtures, and (4) with a new method of additions for XRD.

Methods (2) and (4) gave the best results. Method (2) has a precision of 16.9 pet at the 0.1 wt% level and a LLD of 0.05 wt% at 3σ. Method (4) is particularly attractive because large spikes can be used which minimize homogenization errors and permit preparation of standards which have properties very similar to run-of-the-mill samples; the problem of non-zero intercepts is avoided.
Focusing W Kα1 with a Curved Si Crystal
Authors: Short M. A. , Fallon M. R. , Nagel D. J. , Dozier C. M.
Published: March 2019

The design, construction and operation of toroidal focusing X-ray monochromators have been described in detail by Marcus, et al. (1980) and by Furnas, et al. (1982), Marcus, et al. used 100 mechanically damaged, singly bent LiF (200) (2d = 4.02 Å) single crystals in a toroidal array to focus Cu Kα characteristic X-rays (8.04 keV, 1.54 Å, Θ = 22.6 deg). The diameter of the LiF toroid was 166 mm and the source-detector distance was 400 mm. Furnas, et al. used a series of singly bent, highly oriented graphite (2d = 6.72 Å) crystals, also in a toroidal array, to focus Pb Lα, Se Kα, Th Lα and U Lα X-rays (10.5 - 13.6 keV, 1.18 - 0.91 Å, Θ= 10.1 - 7.8 deg). Their system dimensions were not disclosed. The LiF and graphite crystals were both curved along the direction of X-ray propagation. That is, the cylindrical axes were orthogonal to the X-ray path.
Dependence of Stress Constant on Microstructure of Quenched and Tempered Steels in X-Ray Stress Measurement
Authors: Kurita Masanori , Saito Akira
Published: March 2019

The residual stress measurement of quenched and tempered steels is of practical importance because the quenching can sometimes induce the high residual stress which affects the strength of materials. The stress constants of carbon steels quenched and tempered at various temperatures were measured in order to determine the residual stress of steels by x-ray diffraction. The stress constant increased slowly with increasing tempering temperatures below 500°C; it increased rapidly with tempering temperatures above about 500°C, This rapid increase in the stress constant is closely related to the change in microstructure of the steels in tempering; above the tempering temperature of around 500°C, the tempered martensite recrystallized and transformed to ferritic iron and fine cementite particles dispersed in the matrix; these coalesced and grew to be speroidized cementites and finally laminar cementite plates.
New Directions in the X-Ray Diffraction Analysis of Organic Materials
Authors: Jenkins Ron
Published: March 2019

The analysis of crystalline organic phases by X-ray powder diffraction presents special problems, beyond those typically associated with inorganic materials. The large unit cells often associated with organic compounds, combined with the low symmetry of the structures, give rather complicated diffraction patterns which contain many low angle lines. The Bragg-Brentano geometric arrangement employed in most commercial diffractometers gives maximum d-spacing error at low diffraction angles. This, in turn, means that not only can the large d-spacing data be of poor quality, but also that much of the low angle data required for the indexing of the pattern is subject to large errors.
Preliminary Study Of the Behavior Of HPGe Detectors With Ion Implanted Contacts in the Ultralow-Energy X-Ray Region
Authors: Slapa M. , Chwaszczewska J. , Jurkowski J. , Latussynski A. , Huth G.C. , Dabrowski A.J.
Published: March 2019

Preliminary study of performance of an HPGe detector with an ion implanted entrance window in the spectrometry of the ultralowenergy x-rays is presented.

For the first time it has been shown that almost symmetric photopeaks and absence of low energy tailing can be obtained in this region from HPGe detectors.
X-Ray Diffraction and Fluorescence in the Analysis of Pharmaceutical Excipients
Authors: Durbetaki A. J. , Quail T. F.
Published: March 2019

The majority of pharmaceutical dosage forms are marketed as tablets which are formulated to satisfy various basic requirements. The analysis of the resultant multicomponent pharmaceutical and product is usually a lengthy task.

This paper describes the complementary use of X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRS) to characterize and quantify excipients in pharmaceutical tablets.
Internal Strain (Stress) in an Sic/Al Particle-Reinforced Composite
Authors: Ledbetter H. M. , Austin M. W.
Published: March 2019

Silicon carbide and 6061 aluminum alloy possess very different thermalexpansion coefficients; 3-3 and 22.5.10-6K-1, respectively. Thus, one expects large internal strains and stresses in these composites because the two constituents form interfacial bonds at high temperatures and are cooled to ambient temperatures. From a simple elastic model, one expects a hydrostatic tensile stress in the aluminum matrix and a-hydrostatic compressive stress in the silicon-carbide particles. Using conventional diffraction geometry, using Cu Kα radiation, we studied three surfaces of a plate specimen. For both phases, we determined the unit-cell dimensions for two situations: unmixed and mixed in the final composite. The silicon-carbide particles showed a compressive stress and the aluminum matrix a tensile stress, seventy-five percent of the yield strength. Measurements show that both stress tensors are approximately hydrostatic.
Measurements of the Special Distribution Emitted From X-Ray Spectrographic Tubes
Authors: Arai Tomoya , Shoji Takashi , Omote Kazuhiko
Published: March 2019

The fundamental parameter method for quantitative analysis of composite elements has been a powerful technique for x-ray spectrochemical analysis in which the x-ray intensity and spectral distribution from x-ray spectrographic tubes are the moste ssential factors in the calculating process based on x- ray physics.
Incident and Take-Off Angles for Commercial X-Ray Spectrometers for Use With Fumdamental Parameter Software
Authors: Leyden D.E. , Bilbrey D.B.
Published: March 2019

In recent years there has been substantial development of computer programs which permit the computation of elemental concentration in a variety of samples from basic principles of X-ray absorption and emission. These prog rates are generally called "fundamental parameter" programs. For many years these programs required large main frame computers for execution. An example is the well known NRLXRF program. For the past few years, programs have been available for minicomputers such as the PDP/11 OR LSI/11 systems. The XRF-11 program from Criss Software, the SAP3 program from Batelle Pacific Northwest Laboratory. and a variety of programs from the X-ray instrumentation vendors are examples. Some fundamental parameter programs have been available for several years that can be executed on microcomputers or the so-called personal computers. Some programs use an "effective wavelength" approximation of the tube output to simplify computations.
Soft X-Ray Instrumentation for Space Experiments
Authors: Reidy W. P.
Published: March 2019

This paper will discuss some of the techniques used for soft x-ray astronomy (10 kev - 0.5 kev). A more extensive treatment will be found in review papers by Giacconi, Reidy, Vaiana, Van Speybroeck and Zehnpfennig and by Giacconi, Gursky and Van Speybroeck. The earliest experiments in x-ray astronomy were performed using mechanically collimated small area ( ∼ 10 cm2) geiger tubes flown in open stabilized rockets. Subsequent improvements in sensitivity have resulted from the use of much larger ( ∼ 1000 cm2) counters and improved background rejection techniques. Important spectral information has been obtained by using gas counters which are operated as proportional counters rather than as geiger tubes and the development of the modulation collimator has significantly improved the obtainable angular resolution. The most promising new technique for x-ray astronomy is the development of grazing incidence x-ray optics .
The Application of X-Ray Data to the Determination of Atomic Energy Level
Authors: Burr A. F.
Published: March 2019

Atomic energy levels, which represent the energy necessary to remove an electron in a given level from the atom, are used for a variety of purposes-from predicting possible interfering x-ray lines in analysis to serving as experimental values with which to compare the results of complicated computer calculations. X-ray wavelength data is essential to determine energy level differences but cannot be used to place the resulting level scheme on an absolute energy basis , X-ray absorption data can be so used but the results of photoelectron energy measurements are superior. Since there are a very large number of possible x-ray lines from a typical element, one can readily obtain many more energy differences than there are energy levels ; hence, to make the best use of the data available, a least squares fitting procedure is used to obtain the most probable value for each energy level,
A New Method for yhe Determination of the Texture of Materials of Cubic Structure From Incomplete Reflection Pole Figures
Authors: Ruer Daniel , Baro Raymond
Published: March 2019

The main characteristics of a new method of texture analysis are presented as well aa a comparative study of the results obtained with three different methods.
Polarized Radiation Produced by Scatter for Energy Dispersive X-ray Fluorescence Trace Analysis
Authors: Ryon Richard W.
Published: March 2019

Polarized x-radiation produced by scatter at 90° from boron carbide is shown to be a superior excitation source for the measurement of trace elements by energy dispersive x-ray fluorescence. In a close-coupled system which uses a high power x-ray tube as the primary source, the losses due to the geometric requirements and scattering efficiency of the polarizer can be more than compensated. With the system described here which uses a Mo anode x-ray tube, detection limits for the element between K and Sr in NBS orchard leaves are approximately 2 to 4.5 times lower using polarized excitation in comparison to direct excitation, and about <1 to 3 times lower in comparison to secondary excitation.
Search/Match Implications of the Frequency Distribution of "D" Values in the JCPDS Powder Data File
Authors: Toyohisa Shozo , Fujiwara Iwao , Ui Takuji , Asada Eiichi
Published: March 2019

Interplanar spacings (d values) from X-ray powder diffraction data occur over a wide range of values for the phases that have been described to date. They are not; however, uniformly distributed; rather, the d values are concentrated near certain values and thinly distributed in other regions, We have investigated the possibility of utilizing this distribution of d's to develop a search/ match method for phase identification. We found that there exist single d values that can be unique or almost unique to a certain phase. Also, the number of phases that could be uniquely characterized by single d's was increased by limiting the classes of compounds that were searched. The use of such characteristic d values resulted in a simpler search/match procedure.
Time Share Computer Capability for Phase Identification by X-Ray Diffraction
Authors: Wims Andrew M.
Published: March 2019

In the past, we were limited to manual methods for the identification process. Identification was done manually with a data base of reference spectra (in card and search manual format) supplied by the Joint Committee on Powder Diffraction Standards (JCPDS). Most single substances can be identified with relative ease using this approach. But when the number of components gets much beyond two, the measured pattern is a complex composite of sub-patterns which makes the identification a tedious and uncertain process taking 60 to 90 minutes per pattern in most simple cases.
Bragg-Borrmann X-Ray Spectroscopy from a Line Source
Authors: Das Gupta K.
Published: March 2019

Earlier, I reported in this conference the results obtained with (i) a three crystal spectrometer (ii) two curved crystal spectrometer of Cauchois type and (iii) spherically bent crystal spectrometer. These instruments were developed to obtain higher resolution that helped us to observe fine structures of Kα1, Kα2 lines of transition elements. Our work has been followed in other laboratories.

Here I present the essential points of a very simple spectrometer hitherto unreported. The most attractive feature of the spectrometer is its simplicity of adjustment in a minimum time.
Software Packages for the Automatic Assessment of XRF Data for Qualitative and Semi-Quantitative Analysis
Authors: Warren P. L. , Smith A. E. , Aalten J. D. V. , Hodkinson N.
Published: March 2019

Qualitative inorganic analysis is required for the identification of unknowns, the classification of type, and sometimes to decide what subsequent quantitative analysis is needed. The traditional way of performing qualitative XRF analysis on unknown materials is by subjecting the sample to a full spectral scan. This takes time and an experienced operator to interpret the spectra. Classifying the elements detected as major, minor or trace can also be person dependent. Round robin tests have confirmed this by showing considerable variation in results between laboratories.
Layer Thickness Determination of Thin Films by Grazing Incidence X-Ray Experiments using Interference Effect
Authors: Sakurai Kenji , Iida Atsuo
Published: March 2019

A novel method using Fourier transform algorithm is proposed to determine each layer thickness of multi-layered thin films from interference oscillation observed in X-ray specular reflection. The peak position in Fourier space gives each layer thickness of the film. The principle of the present technique as well as its applications are described.
Light Element Analysis with TXRF
Authors: Streli Christina , Wobrauschek Peter , Aiginger Hannes
Published: March 2019

Total Reflection X-Ray Fluorescence Analysis (TXRF) has become a powerful analytical tool for trace element analysis. Because of its advantages in excitation and background reduction TXRF has been applied for the analysis of light elements (C,O,F,Na,...). A special Ge(HP) detector offering an ultra thin window in combination with a spectrometer specially designed for the requirements of light element analysis was used. Also a new windowless X-ray tube for efficient excitation of the light elements was tested. The system was checked with standard aqueous solutions; detection limits in the ng range (7 ng for O) are obtained.
Application of TXRF in Environmental Research
Authors: Michaelis Walfried , Pepelnik Rudolf , Prange Andreas
Published: March 2019

In the framework of interdisciplinary research projects TXRF has been applied for multielement analysis of rainwater, size-fractionated airborne particulates, throughfall samples and litter fall in forests, soil solutions, seepage water, river water filtrates and suspended particulate matter. Essential aspects of sample preparation techniques are briefly described. Some results are given on trace element fluxes in a forest ecosystem and on contaminant transport phenomena in estuaries in order to demonstrate the outstanding capabilities of TXRF in demanding environmental research projects.
Measurement of Macrosegregations of Steels by X-Ray Microfluorescence
Authors: Welfringer J. , Benoit P. , Guyon M.
Published: March 2019

An apparatus based on X-ray microfluorescence has been developed at IRSID in order to routinely and quantitatively determine the state of segregation in steels. The equipment consists principally of an iron anticathode X-Ray tube, a Si(Li) energy - dispersive detector and a “on the fly” operation in a multi-scale analysis mode. The acquisition of a chromium or manganese mapping in a (150 × 150 mm2) steel sample is possible over a total time of about one hour. The calibration curves for chromium or manganese are linear for the usual compositions of steels between 0.3% to 3%.
Coordination Analysis by High Resolution X-ray Spectroscopy*
Authors: Bai You-Zhao , Fukushima Sei , Gohshi Yohichi
Published: March 2019

Various X-ray fluorescence spectrometers are now commercially available, and these spectrometers are classified into two categories, i.e., energy dispersive and wavelength dispersive (Table 1). Energy dispersive instruments are of low resolution. Wavelength dispersive instruments are often referred to as high resolution. However, commercially available wavelength dispersive instruments are usually equipped with a one-crystal dispersion unit. Therefore, to be more precise, these instruments could be called medium resolution apparatuses. There are other types of spectrometers which are two- or three-crysral spectrometers, and which are known to have very high resolving power. High resolution X-ray fluorescence spectrometers, however, have rarely been constructed. This is because this type of spectrometer needs a very precise and complicated scanning mechanism, and also because the intensity of X-ray fluorescence is often lost.
The Application of Tunable Monochromatic Synchrotron Radiation to the Quantitative Determination of Trace Elements
Authors: Giauque R. D. , Jaklevic J. M. , Thompson A. C.
Published: March 2019

The potential advantages of synchrotron sources for x-ray fluorescence analysis have been discussed by several authors. These advantages include high incident flux, tunable excitation energies using crystal monochromators, and reduction of scattered background due to polarization effects. Minimum detectable limits have both been calculated and measured, and have demonstrated the improvements that can be achieved vising synchrotron sources. In this paper we present results obtained using tunable, monochromatic excitation and a high resolution lithium-drifted silicon, Si(Li), spectrometer for the quantitative analysis of a variety of sample types. Our experiments were designed to investigate the advantages and limitations of tunable monochromatic excitation with respect to optimum sensitivity, accuracy, and elemental selectivity in energy dispersive x-ray fluorescence analysis.
The Rapid Simultaneous Measurement of Thermal and Structural Data by a Novel DSC/XRD Instrument
Authors: Fawcett T. G. , Crowder C. E. , Whiting L. F. , Tou J. C. , Scott W. F. , Newman R. A. , Harris W. C. , Knoll F. J. , Caldecourt V. J.
Published: March 2019

Over the past 25 years, numerous studies utilizing both X-ray diffraction (XRE) and differential scanning calorimetry (DSC) have been reported In the literature. Generally, conventional high-temperature X-ray data identifies solid-state transitions, then attempts to correlate them with thermal events observed by the calorimeter. Since changes occur in the sample during studies such as these, separate portions of the sample must be used for XRD and DSC experiments. When comparing results of the two experiments, questions arise concerning sample homogeniety as well as temperature and environmental differences. In fact, no conventional high-temperature X-ray diffraction instrument can give the precise control over temperature and heating rate available with a DSC, The problems of sample inhomogeneltles and Instrumental differences could be avoided if X-ray diffraction and DSC could be performed simultaneously on one sample.
Determination of the Unstressed Lattice Parameter “a0” for (Triaxial) Residual Stress Determination by Xrays
Authors: Noyan Ismail Cevdet
Published: March 2019

Stress gradients in the direction of the surface normal influence the shape of the interplanar spacing “d” vs. sin2ψ (where ψ is the specimen tilt) plot obtained from the surface layers of a specimen.(1-3) If the gradients are caused by the shear stresses σ13, σ23, the “d” vs. sin2ψ plot exhibits “psi-splitting”, that is the “d” values measured at positive ψ tilts are different from the values measured at negative if tilts. (2) If the shear stresses σ13, σ23, are zero, but the normal stress σ33 exists in the layets penetrated by the x-ray beam, “d” vs. sin2ψ, plot exhibits curvature. (3) Various methods have been proposed to obtain the complete stress tensor from split or curved “d” vs. sin2ψ data, and all of these methods require the “unstressed” lattice spacing “d0” for their calculations.
Chemical Bonding Studies of Solutions by High Resolution X-ray Fluorescence Spectroscopy
Authors: Scimeca Tom , Fukushima Sei , Miyamura Kazuo , Gohshi Yohichi
Published: March 2019

High resolution X-Ray Fluorescence Spectroscopy(HRXRFS) has been extensively used as a chemical bonding probe for both solids and gases for quite some time. However there have been virtually no HRXRFS studies reported on liquid phase systems and particularly on solution systems. This seems somewhat surprising not only because this is an unexplored area, but because much of chemistry and chemical bonding occurs in solution. Furthermore, since HRXRFS is a “photon in - photon out” technique, providing one uses relatively energetic x-rays, the experimental techniques for performing these types of measurements are relatively straightforward, especially when compared to techniques which utilize charged particles.
Practical Application for the Use of Statistics to Establish Quality Control and Implement Quality Assurance in X-ray Fluorescence
Authors: Ruggiero Philip A.
Published: March 2019

Increasing demands are being placed on the supervisors and operators of laboratories using XRF to establish the capability of their instruments in order to comply with internal requests and to meet customer quality assurance requirements through an audit procedure. To quantify just how accurate or precise the instrumentation is, a baseline must first be established on the instrument capability. Once the capability is documented, the precision of the instrument can be established and detection limits can be calculated. Establishing the capability of the instrument can provide a basis for developing a quality assurance procedure.
Graphite Fusion of Geological Samples
Authors: Luedemann Gary , Mann David , Hagan Roland
Published: March 2019

Proper sample preparation is very important for quantitative X-ray fluorescence analyses. Our first approach to fusing geological samples was a slight modification of a method described by Taggart(l) of fusing in platinum crucibles, with 1 g of sample to 10 g lithium tetraborate fired over bunsen burners. This method provided good results and was used until recently. Due to physical constraints, the required exhaust hoods could not be installed which prompted our investigation into new methods of fusion. The first reported application of a borate-glass fusion was in 1913(2); the melt consisted of 0.3 g of sample, 1.5 g of lithium carbonate, and 1.5 g of boron oxide (or about 3 g of lithium tetraborate). This mixture was heated in a graphite crucible at 1150 °C for twenty minutes and then poured into a brass ring on a copper-surfaced hot plate. Ironically our current procedure resembles this early technique.
Phase Analysis of Metallic Plutonium-Containing Fuel Alloys Using Neutron Diffraction
Authors: Mueller M. H. , Richardson J. W. , Strain R. V. , Hofman G. L.
Published: March 2019

Pulsed neutron powder diffraction studies at IPNS have expanded our understanding of the phases present in Integral Fast Reactor (IFR) metal fuel alloys at temperatures in the range of reactor operating conditions. We report results from the binary alloy (U-10wt.%Zr) and ternary alloys (U-8%Pu-10%Zr) and (U-19%Pu-10%Zr). Determining the role and the location of Zr and Pu in these alloys is considered of fundamental importance for maximizing engineering efficiency.

Rietveld profile analysis was utilized to study the phase diagrams. Data were collected at temperatures ranging from 25-650°C. Although the expected U/Pu/Zr phases (α-U, β-U, γ-U, δ-U/Zr/Pu, ζ-U/Pu) were observed in appropriate temperature ranges, there were some unexpected results. Relative amounts of all phases at each temperature were calculated from Rietveld scale factors and inferences were made as to the location of zirconium and plutonium, i.e. amounts in each phase, from site occupancies and absorption characteristics of the phases present. Finally, we were able to identify ZrO and ZrO1-x inclusion phases in the U-Zr alloy present in very small (0.5-1.0%) amounts.
X-ray Elastic Constants for β-SiC and Residual Stress Anisotropy in a Hot-Pressed Al2O3/SiC(Whisker) Composite
Authors: Predecki Paul , Abuhasan Alias , Barrett Charles S.
Published: March 2019

X-ray elastic constants for the 511+333 and the 422 reflections of β-SiC were calculated from the single crystal data of Tolpygo using the Voigt-Reuss, Eshelby-Kroner and x-ray methods. Agreement was satisfactory for the 511+333, but less so for the 422. A hot-pressed α-Al2O3/ 29 vol % β-SiC (whisker) composite was investigated on its 3 principal faces. The total residual strains were found to be consistently anisotropic on all 3 faces suggesting that texture was present in the whiskers as a result of hot-pressing. Assuming no texture in the matrix, it was found possible to determine the average residual microstresses in the whiskers using the theory of Noyan and Cohen, without needing to know the whisker elastic constants or texture. The average microstresses were determined in each phase as well as the average residual macrostresses on each face.
Residual Stresses in Unidirectional Al2O3 Fiber/Silicate Glass Composites by X-ray Diffraction
Authors: Hehn Lucien , Predecki Paul
Published: March 2019

Unidirectional continuous fiber composites fabricated from 20 μm diameter α-AI2O3 fibers (duPont FP) and 5 different silicate glass matrices (Corning 9013 and 7740, Owns Illinois N51A and Schott 8229 and 8228) were examined for residual strain and stress in the fibers using x-ray diffraction and the results compared with the predictions of two simple residual stress models. The glasses were chosen to have thermal expansion coefficients ranging from 1.3 to 10.2 x 10-6 /°C, compared with 7.2 x 10-6 /°C for the fiber, so as to produce a range of residual stresses. The magnitudes of the measured normal strains and stresses increased with increasing fiber/matrix thermal expansion mismatch in the order expected except for the sample containing Corning glass 7740 which showed extensive microcracking. Small shear strains were also detected in most of the samples due to the fibers not lying precisely along the presumed uniaxial direction. Agreement with the models was qualitative only but revealed that the residual stresses in the samples containing Corning 7740 and Schott 8229 glasses were substantially less than expected, possibly due to microcracking and/or fiber degradation.
Standardless Thickness Measurement of Steel Coatings by X-Ray Fluorescence Spectrometry
Authors: Ohno Katsumi
Published: March 2019

Because the cost of the large number of standards required for quantitative X-ray fluorescence analysis is prohibitive, a mathematical procedure, the “fundamental parameters method” is gaining popularity. A major problem in using the method is the limited knowledge of the spectral distribution of the primary radiation from the X-ray tube, the need for a large computer memory which makes it difficult to use with minicomputers and uncertainties in the basic parameters. A monochromatic X-ray source was developed to avoid the problem of the spectral distribution. This permitted simple calculations for the calibration and a simple algorithm to transform the intensities to mass fraction or coating thickness. The calculations were made with a slide rule calculator.
Measuring Triaxial Stresses in Embedded Particles by Diffraction
Authors: Barrett C. S. , Predecki P. K.
Published: March 2019

The method presented In 1976 for measuring stresses in polymeric materials including fiber-reinforced composites (1,2) yielded directly only one or two of the principal stresses and (elastic) strains in the embedded crystalline particles. The method is now extended so as to yield determinations of all three principal stresses σ1, σ2, σ3 and strains, ε1, ε2, ε3, The method applies to both residual and applied stresses and strains.

High angle diffractometry such as is used in ordinary X-ray stress determinations in metal objects is used, with suitable particles being embedded in a homogeneous plastic or reinforced composite before curing.
Application of X-Ray Examination to Fracture Surface of Ti A1 Intermetallic Compound
Authors: Tabata Hiroyukt , Yajima Zenjiro , Sasaki Toshihiko , Hirose Yukio
Published: March 2019

Titanium aluminide base allays are new materials of interest with exellent potential for high temperature structural applications. Several studies on the fracture toughness of these alloys have been reported and the beneficial effect of lamellar microstructure consisting of Ti3Al(α2) and TiAl(γ) has been detected. While these studies indicate such an enhancement of the fracture toughness is caused by micro-crack toughening, SEM observation alone is insufficient to clarify the fracture mechanism.
Measurement Of Retained Austenite in Stainless Steel Using Imaging Plate
Authors: Sasaki Katsunari , Hirose Yukio , Sasaki Toshihiko
Published: March 2019

There are several methods for the measurement of retained austenite in steels, which influences mechanical behavior and corrosion resistance of steels. Among them, X-ray diffraction methods using a wide angle goniometer or X-ray stress analyzer are commonly used because the methods are non-destructive, giving useful information about residual stress or lattice strain as well.
Why The Fundamental Algorithm is So Fundamental
Authors: Rousseau Richard M.
Published: March 2019

In X-ray fluorescence (XRF) analysis, one of the major problems is the correction for matrix effects (absorption and enhancement). One of the solutions proposed was the use of influence coefficients, which are numerical coefficients that correct for the effect of each matrix element on the analyte. For many years, these coefficients were considered as an empirical approach having little connection with X-ray fluorescence theory. They were considered useful only when no other alternative was available to solve the problem of matrix effect.
Characterization of Laterites by X-Ray Techniques
Authors: Chandra D. , Ruud C. O. , Barrett C. S. , Siemens R. E.
Published: March 2019

To assure an adequate supply of such critical metals as nickel and chromium, extraction procedures must be developed to process low grade domestic sources. In optimizing these procedures it is essential to use suitable analytical procedures to characterize the materials, identify phase transformations, and determine metal and mineral association of the critical metallic elements through all stages of the process. Evaluation of complex sources such as laterites requires special material handling techniques coupled with X-ray diffraction and with optical and SEM analyses of many individual particles. A joint study by the Bureau of Mines and the Denver Research Institute using these procedures has resulted in optimizing a new modification of an extraction process.
X-Ray Strain Measurements in IV-VI Semiconductor Super-Lattices at Low Temperature
Authors: Fantner E.J. , Clemens H. , Bauer G.
Published: March 2019

Multilayers composed of many thin films of PbTe and Pb1-xSnxTe on BaF2 substrates were grown epitaxially by hot-wall-vapor deposition. In order to investigate the fraction of the total misfit (2.5x10-3 at x=O, 12) accommodated by misfit strain we have performed strain measurements on these superlattices by two different X-ray diffractometer techniques. We also report on substrate induced strain due to different thermal expansion coefficients of films and substrate. For film thicknesses smaller than 300 nm there is clear evidence for almost complete accommodation of lattice mismatch by misfit strain. Below room temperature the substrate induces a tensile strain which is comparable to that of the misfit strain.
Stress Measurement at Fatigue Crack Tip using PSPC
Authors: Yoshioka Yasuo
Published: March 2019

The growth of fatigue crack builds up the compressive residual stress with the plastic zone in front of the crack tip. The presence of this residual stress is one of the main causes for the crack closure. The consequence of residual stress is a reduction of the crack tip stress intensity variation during a load cycle. Although this effect is well understood in a qualitative manner, it has not been completely quantified because of a lack of information about the load and residual stress distributions at the crack tip.
X-Ray Fractography on Stress Corrosion Cracking of High Strength Steel
Authors: 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. The line broadening of X-ray diffraction profiles and the residual stress are two of the important X-ray parameters. Among them, the X-ray residual stress has been confirmed to be particularly useful for the fracture surfaces of high strength steels, and applied to the fracture surface of fracture toughness specimens and the fatigue fracture surface.
A Low Cost Rejuvenation of Old G.E. and Picker X-Ray Generators
Authors: Raykhtsaum G. , Georgopoulos P.
Published: March 2019

General Electric (G.E.) and Picker generators are currently installed in many research laboratories all over the United States. These units are old and do not satisfy the modern requirements for X-ray generators. Instabilities of high voltage and tube current complicate the experiment. To maintain G.E. and Picker generators is becoming more and more expensive due to the high cost of vacuum tubes and replacement parts. To replace old generators with new high performance commercial units can cost even more and requires additional adaptations. In the present paper another alternative is proposed, which assumes the replacement of vacuum tube mA and KV controls with solid state circuits using the old G.E. or Picker high voltage transformers. This alternative allows rejuvenation of old generators without difficulties of reinstallation and does not require adaptations to the existing experimental X-ray equipment. The combination of old high voltage transformers with modern solid state control devices provides high performance at low cost. For this purpose the control device was designed and is described below.
X-Ray Tube Improvements for Better Performance in an Energy-Dispersive X-Ray Spectrometer System
Authors: Vane Ronald , Skillicorn Brian
Published: March 2019

Improvements in x-ray tube technology for the low-power tubes used in energy-dispersive XRF systems can provide better performance. These improvements are occurring in six areas: thin-window tubes, lower kV capability, higher kV and mA capability, pulsed tubes, smaller focal spots, and miniaturization. These improvements will lead to better excitation of the light elements, analysis of low-mass samples, higher count rates, small spot analysis, and smaller systems.
Lama III - A Computer Program for Quantitative XRFA of Bulk Specimens and Thin Film Layers
Authors: Mantler Michael
Published: March 2019

The previous LAMA I and II programs have been completely rewritten in this new version. Better precision and an order of magnitude increase in speed were achieved with a different numerical method and more efficient code. Fundamental parameters and/or empirical parameter calculations can be used. New routines for the analysis of oxides and other compounds of light elements, and multiple thin film layers with secondary enhancement factors are included.
A Rapid, Low Cost, Manual Fusion Sample Preparation Technique for Quantitative X-Ray Fluorescence Analysis
Authors: Bowling Gerald D. , Ailin-Pyzik Iris B. , Jones David R.
Published: March 2019

This study compares the quality of the fused samples obtained by three separate methods. The first set of samples was prepared by the method used at USGS in Denver and reported by Taggart and Whalberg (1). The second set was fused by our manual method and cast in graphite molds. The third set was fused in the Herzog HAG-12 automated fusion device.

The manual fusion technique requires the use of a muffle furnace capable of 1100°C (2100°F) and graphite molds. No release agents such as KBr and LiBr are required since the disks release easily from the graphite. The 25mm diameter center of the “fire-polished” upper surface of the disk is used for analysis without further surface preparation. This method has been shown to be suitable for preparation of a wide variety of glasses and raw materials including burned dolomite, silicates* high zircon materials such as BCS-388, calcined alumina and alumina refractories.
Quantitative XRFA of Light Elements by the Fundamental Parameter Method
Authors: Mantler Michael
Published: March 2019

Analysis of light elements, such as C, B, and Be, differs from analysis of heavier elements by the low fluorescent yields as well as by the wide gap between their absorption edge energies and the low energy limit of the available tube-photons. Because of the fact that the (relatively large) difference between these energies is transferred to the photoelectron after an ionization event, additional excitations of light elements are very likely to occur. Other possibilities of unusual secondary excitation effects include excitation by Auger electrons and by Lα-photons after K-shell ionization. The order of magnitude of these effects has been computed for the system Fe/Fe3C. The mathematical models are based on the methods of Green and Cosslett, and Scott and Love. Results show that the C-Kα counts of pure carbon are increased by a factor 2.5-3, and count rate ratios in Fe-C binary systems increase by a factor 5-10, depending upon the experimental conditions. Fit coefficients for mass absorption coefficients of Fe and C have been calculated from experimental data collected by Saloman and Hubbel for energies between 100eV and 1keV.
XRF Analysis of Pb in Occasional Paint Chips
Authors: McKee Chris , Renault Jacques
Published: March 2019

Federal laws require that urban redevelopment projects characterize the Pb hazard of old painted surfaces. In large metropolitan surveys, the Pb analyses are commonly obtained with a portable XRF unit; however, for small surveys, capital investments in such instrumentation may be unwarranted. In 1988, the city of Las Cruces, NM, requested our help in providing needed Pb in paint analyses. We developed an economical XRF method for Pb analysis suitable for small scale urban surveys and the requirements of individual home owners, it is described below.

1) A standard wavelength dispersive XRF spectrometer is used to determine the CI countrate from a 3.6 cm KCl disk and the countrate per square cm is computed. 2) The paint chip is weighed to the nearest 0.1 mg and cemented onto the disk. 3) The prepared disk is counted for CI, Pb, and Rb using the same spectrometer. 4) The CI countrate deficit is used to compute the area of the paint chip. 5) The mass of Pb corrected for Rb interference is determined from an appropriate calibration curve, and the results are reported in mg Pb/cm2.

The Pb analysis is calibrated against geochemical standards. Spex Mix containing Pb is sprinkled on double faced mylar tape of known area and used as an independent check on the calibration curve. We present the results of our calibration curves and our analytical experience over the last 5 years.
Quantitative XRD Analysis of Advanced Coal Combustion Solid Residuals by the RIR Method
Authors: Bender J.A. , Solem J.K. , McCarthy G.J. , Oseto M.C. , Knell J.E.
Published: March 2019

Reference intensity ratios (RIRs) with zincite (ZnO) as the internal standard have been measured and calculated for key phases in coal combustion solid residuals. Detailed comparisons of measured and calculated corundum RIRs (converted from zincite RIRs), and literature I/Ic values led to the conclusion that for best results, laboratory measured values must be used. Using measured zincite RIRs and standard mixtures of important crystalline phases, a protocol for routine semi-quantitative analysis has been developed. The need to grind under ethanol to minimize decomposition of hydrated phases was demonstrated. An unusual procedure employing mixed peak and integrated intensities in the RIR of one key phase, ettringite (Ca6Al2(SO4)3(OH)12-26H2O), has been adopted for this protocol.
Application of Grazing Incidence X-Ray Diffraction to Polymer Blends
Authors: Garbauskas Mary F. , LeGrand Donald G. , Goehner Raymond P.
Published: March 2019

The physical properties of polymer blends consisting of one or more crystallizable components are affected by the microstructure of these materials. In particular, the degree of crystallinity can be influenced by processing parameters, and the crystallinity, as well as the phase distribution, may vary as a function of depth through an injection molded part. Conventional x-ray diffraction techniques can provide information regarding both phase composition and degree of crystallinity, but, because of the relative transparency of these materials to wavelengths generally available in the laboratory, these techniques provide information representative of only the bulk. By employing parallel beam optics at varying grazing incidence angles, the x-ray sampling depth can be varied without loss of resolution, This technique can be used to vary the effective analysis depth from the top several hundred angstroms for low grazing incidence to centimeters for transmission diffraction patterns, Grazing incidence techniques have found initial application in the characterization of thin metallic and ceramic films. This paper demonstrates the feasibility of using parallel beam optics to depth profile low atomic number materials. The specific application of this technique to the characterization of injection molded polymers, including a blend of bisphenol-A polycarbonate (PC) and polybutylene terephthalate (PBT), will be presented.
The Temperature Profiles along Heating-Strips in High Temperature Chambers for XRD
Authors: Ebner R. , Mantler M. , Weber F.
Published: March 2019

A prototype of a new high temperature chamber has been developed at our institute. Like most of such chambers it has an evacuated housing which is watercooled, and in its center a tungsten heating strip is mounted on watercooled clamps (fig.1). A special way of clamping compensates for thermal expansion automatically and thus keeps the specimen in an aligned position. The specimen is mounted directly onto the heating strip's surface. Specimens are prepared using fine powders mixed with distilled water and acetone to give a thin slurry. This mixture is put onto the heating strip and carefully dried with a heatgun. This way of preparing a specimen makes it cling to the heating strip quite well even at temperatures above 3000K and therefore provides good thermal contact.
Determination of the Coherency Strain of γ and γ′ Phases in Nickel-Base Superalloys at High Temperatures
Authors: Ohno Katsumi , Yokokawa Tadaharu , Yamagata Toshihiro , Harada Hiroshi , Yamazaki Michio , Ohsumi Kazumasa
Published: March 2019

A method for using syncrotoron-radiation parallel-beam X-ray diffractometry for precise lattice parameters and strains of γ-γ′ type Nickel base superalloys at elevated temperature is described. The superalloys have γ′ precipitates which are an ordered L12 structure based on Ni3Al, in y-matrices having a disordered FCC structure. Lattice misfit between γ and γ′ phases was very small and peaks reflected from γ and γ′ phases made unresolved clusters of peaks.

Profile fitting with a pseudo-Voigt function is used to resolve overlapping peaks. Instrumental broadening of the peak profile was removed using a deconvolution method. The standard errors of the calculated peak angle were less than 0.002°. The elastic strain of the γ′ precipitates in the alloys were smaller than those of γ-matrices.
A New Position Sensitive Detector for X-Ray Diffractometry
Authors: Radtke J. L. , Beard D. W.
Published: March 2019

Position sensitive detectors provide efficient X-ray detection over large solid angles; this capability has revolutionized X-ray diffractometry by reducing data collection time. This paper describes testing of a new single-axis position sensitive detector designed to locate 0.6-2 Angstrom X-rays. Dead time, quantum efficiency, energy resolution, and spatial resolution were measured. Standard powder diffraction patterns were observed with the detector, and data sets are presented. The impact of detector performance parameters on diffraction experiments is discussed.