bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dilemma of Anomalous X-Ray Reflections
Authors: McGee James F. , Olli Veil I.
Published: March 2019

That X-rays focused by reflection from concave surfaces exhibit anomalous image broadening was shown by Ehrenberg using a line source. Even flat nonfocusing surfaces of many different materials produced an anomalous striated reflection. According to Ehrenbevg, the common cause for the observed broadening in the focused image and the striated pattern in the nonfocused reflection is a periodic surface structure. In later years, Eliot, using a point source of X-rays reflected from a concave surface, observed a striated pattern at a position well beyond the focal plane. It is to be noted that Eliot's experiment combined elements of Ehrenberg's two experiments—a focusing surface and observations made far from any focal plane, real or virtual. Eliot observed his striations with fused silica surfaces but not with obsidian. Recently, Yoneda, using X-rays collimated by a Soller slit and incident on a plane surface, observed an anomalous line reflection not previously reported.

Various experiments performed by the present authors have attempted to duplicate some of the above situations as closely as possible, either directly with X-rays or in an analogous manner with visibic light. It will be shown that satisfactory explanations can be formulated from previously unsuspected diffraction phenomena, recently confirmed by experiment as well as by a simple experimental oversight. In spite of the dilemma presented, either horn eliminates all previous limitations due to surface conditions, so that the tolerable surface roughness is once again determined by the well-known Rayleigh criterion rather than by any periodic surface irregularities introduced through the polishing process or by nature.
A Study of the Unusual Line Structure in Powder Patterns of Pyrolytically Deposited Boron Compounds and Other Materials
Authors: Prickett Robert L. , Hough R. L. , Earley Duane
Published: March 2019

A prolonged study has been roade of the unusual X-ray powder patterns generated by certain pyrolytically formed boron compounds, consisting of two to four moderately broad diffraction lines in the 1-4 Å range. These broad lines are unexpectedly made to disappear by a singie sharp blow with a hammer on the specimen in a Plattner diamond mortar, the disappearance being accompanied by the spontaneous generation of the standard diffraction lines expected for normally crystalline materials. The same diffraction pattern changes also may be brought about by regular grinding methods, fracture, or thermal annealing. Transmission electron diffraction yields results identical with those obtained by X-ray. Orientation studies demonstrate that the phenomenon is not orientation dependent. Controlled fracture has been applied in an attempt to develop a hypothesis. It appears from the constancy of the width and position of the diffraction lines among samples that the phenomenon being studied has a definite potential energy, well located somewhere between amorphous and crystalline states. Demonstration of this phenomenon of line broadening has been obtained with boron, boron carbide, and in part with silicon, carbide. These materials have been formed by various methods: pyrolytic decomposition of carborane, low pressure electrical discharge in diborane, chemical reaction between boron halide and hydrogen.
Anomalous Residual Stresses
Authors: Ricklefs R. E. , Evans W. P.
Published: March 2019

Residual stresses were measured in hardened and tempered specimens after unidirectional plastic extension. X-ray and strain gage-layer removal methods were compared. Anomalous residual stresses were found in extended samples at hardnesses of Rc 32–35. The X-ray method indicated compressive residual stresses of nearly constant magnitude through ⅓ the thickness of flat samples, while the strain gagelayer removal method indicated that no macrostress existed. A constant anomalous residual stress was also seen by X-ray through ⅗ the thickness of a cylindrical specimen deformed uniformly in tension. Little or no anomalous stress was found in an extended specimen at Re 55 or in a specimen at Rc 44 after uniform bending.
Experimental Factors Concerning X-Ray Residual Stress Measurements in High-Strength Aluminum Alloys
Authors: Hilley Michael E. , Wert James J. , Goodrich Robert S.
Published: March 2019

X-ray diffraction as a means of determining stresses has found increasing application in the last few years. This is primarily because it is the only technique by which stresses can be determined without making measurements on the specimen or structure in the unstressed condition and, consequently, it is the only truly nondestructive technique for determining residual stresses. The principles of determining macrostresses on surfaces with commercially available equipment is quite well known and employs either the X-ray diffractometer or back-reflect ion camera techniques. The diffractometer technique was selected for this investigation because of its accuracy and because it allows both macrostresses and microstra in to be analyzed from the change in position and shape of the diffraction peaks. The X-ray analysis actually consisted of two separate phases. The first dealt with the X-ray determination of the elastic constants (Young's modulus and Poisson 's ratio) for several aluminum alloys, including 5083. These values were compared with the theoretical or published values as determined by standard tensile tests and used later in stress calculations. For these tests, a unique stress stage was used which allowed the specimen to be stressed while positioned in the diffractometer, and also have angular rotation about the diffractometer axis that is independent of the rotation of the counter and receiving slit system. The second phase consisted of analyzing different groups of 5083—aluminum alloy specimens which had been subjected to various degrees of cold working by rolling. This analysis consisted not only of the computation of macrostresses, but also of microstrain and change in particle size as a function of percentage reduction in thickness. The final portion of this phase dealt with electro polishing successive layers from the surface of each sample and relating the measured relaxation to the thickness of the layers removed. In this way, stress distribution in depth was obtainable as a function of cold working.
X-Ray Analysis of Fatigue Damage in Copper
Authors: Baggerly Roy G. , Pelloux Regis M. N. , Flanagan William F.
Published: March 2019

A Warren-Averbach1-4 X-ray line profile analysis was applied to broadened X-ray diffraction peaks from copper deformed in fatigue. The copper specimens were fatigued by four-point bending at peak-strain amplitudes between 0.00105 and 0.00442 in./in., and measurements were made at various fractions of the total fatigue life. The analysis results in an estimation of (a) an average coherently diffracting domain size normal to the diffracting planes and (b) an rms strain distribution function where the strain normal to the diffracting planes is averaged over a given distance at all points in the diffracting crystals and expressed as a function of averaging distance.

Prior to fatigue cycling, the annealed copper exhibited extinction, which reduced the integrated intensity from the low-angle reflections. After fatigue cycling, the integrated intensity increased with increasing strain amplitude of fatigue. The integrated intensities and the rms strains were established during the first few percent of the fatigue life and were found to increase with fatigue strain amplitude. The measured strains were larger in the <100> direction than in the <111> direction, but the absolute values were small. On the basis of transmission electron microscopy of thin foils, these results may be explained by assuming the strains are due to the presence of numerous dislocation dipoles.
Improvement of Accuracy in Representation of Conventional Pole Figures
Authors: Aoki K. , Hayami S. , Matsuo M.
Published: March 2019

In the conventional pole figure, an accurate representation can be attained by correcting the observed X-ray diffraction intensity for any change in diffraction geometry and by comparing this with the correctly established standard intensity. For the intensity corrections, ASTM has prescribed the method of Decker et al. In practice, however, the validity of the correction formula is uncertain, since the prerequisite is difficult to attain for parallelism of an incident beam of sufficient intensity. For the standard intensity, it is desirable to take the intensity obtained with the randomly oriented material of the same composition. However, in most cases an arbitrary unit has been taken because of the difficulty in getting a truly random and uniform sample. Under these circumstances, it is first necessary for an accurate representation of pole figures to make a random sample of uniform thickness for the standard. The authors have obtained satisfactory standard samples by sintering the randomly oriented iron powder made from iron chloride and made use of them to check the method of intensity correction. Satisfactory results are obtained in the randomness tests, such as the comparison of the relative intensity diffracted from the crystal planes parallel to the sample surface and the fluctuation of diffraction intensity during α rotation.

In the reflection case by the Schulz method, the (110) reflection intensity of a random sample, by Co Kα radiation, is independent of the tilting angle up to 50°. The other reflections do not give a constant intensity for the wide range of the tilting angles because of dispersion of the diffracted beam due to the wider separation of Kα doublet in the higher reflection angle and the wider irradiated area at the lower angles. In the transmission case Schulz's correction formula is in good agreement with the observed values for the various diffraction lines and the samples of various µt, while the Decker-Harker formula does not give the absorption change with α-rotation even by an incident beam of ⅙° divergence. In both cases, an accurate determination of pole densities is made by comparing the diffraction intensity of the standard sample substituted in place of the test specimen and by correcting the absorption change due to the difference of µt between the standard and test sample, which affords good coincidence in the overlapped region. The pole figure obtained by the above method furnishes an accurate prediction of plastic and elastic anisotropy in sheet metals.
Electron Microprobe Analyses and X-Ray Diffraction Study of SrSi2
Authors: Faulring G. M. , Malizie E. S.
Published: March 2019

Although the phase SrSi2 has been previously recognized, it has been described only briefly in the literature.

An alloy comprised of FeSi2, silicon, and the SrSi2 phase was examined on the electron microprobe. Optical and electron scanning images are correlated with X-ray scanning images for iron, silicon, calcium, and strontium. Quantitative microprobe analyses were made and corrected for absorption and the atomic number effect by several noncomputer methods. The corrections include as variables the X-ray intensities measured at several accelerating voltages. The effects of varying the electron beam size and accelerating potential are included. The results are compared to chemical analyses. The advantages of varying the accelerating voltage when correcting intensity data, increasing the beam size when surface preparation is a factor, and the importance of surface preparation at low accelerating voltages are discussed.

An X-ray diffraction examination showed that the phase SrSi2 has a cubic unit cell with an a0 of 6.515 Å. There are four molecules per unit cell, and the most probable space group appears to be P213. The density was calculated as 3.45 (observed density >3.3).

Metallographic observations with ordinary and polarized light and microhardness measurements are included.
A Glass Fusion Method for X-Ray Fluorescence Analysis
Authors: Larson J. O. , Winkler R. A. , Guffy J. C.
Published: March 2019

A thermally tough, low-melting, low-viscosity glass composition is described that has been used as a fusion mixture in sample preparations for X-ray fluorescence analysis.

The fusion mixture is cast into a glass disk which, after annealing, is used directly for the X-ray measurements. Problems arising from disk surface imperfections have, in the past, been minimized by either prolonged polishing of the glass surface, or grinding the disk and pressing the powder into a peltet. This practice has been eliminated through the incorporation of appropriate internal standard elements into the glass fusion mixture. This approach also minimizes interelement effects and errors due to instrumental drift.

A variety of corrosion products have been successfully analyzed by this method. Results will be given.
Quantitative X-Ray Emission Analysis of Magnesium Through Fluorine with X-Ray and Electron Excitation
Authors: Bernstein F. , Mattson R. A.
Published: March 2019

The analysis of dry powder samples for magnesium, sodium, and fluorine by X-ray and electron excitation has been studied. As in the case of heavier elements, the form of chemical combination influences the elemental sensitivity; sensitivity changes due to self-absorption can be adequately predicted using published absorption coefficients. Where both absorption and enhancement effects are possible, selection of X-ray target or excitation potential can. eliminate the enhancement problem. Matrix effects were found to be extremely variable and unpredictable. Finally, X-ray and electron excitation results are compared for the three elements in a series of geological samples. Efficiency of excitation was far better for electron excitation, but limits of detectability were lower for X-ray excitation due to significantly lower backgrounds.
X-Ray Fluorescence Spectroscopy in the Analysis of Ores, Minerals, and Waters*
Authors: Rose Harry J. , Cuttitta Frank
Published: March 2019

X-ray fluorescence spectroscopy has been used in solving a wide variety of geologic problems involving mineral, ore, and water analysis. The technique has been a powerful analytical tool in the survey of mineral deposits, as a control to monitor ore flotation processes, for the semimicroanalysis of mineral separates and of rare new mineral species, and for the determination of trace elements in lake and saline waters. Many preparation techniques have been developed for the analysis of complex mineral systems, some combining X-Ray fluorescence with other analytical techniques to provide a complete analysis. These, coupled with improvements in instrumentation, have given the X-ray analyst a means of extending analytical ranges to the microgram level and to include elements that were previously not detectable. Significant advances in sample preparation and methods development have been made in the analysis of milligram quantities of complex geologic materials. The fusion and the solution of specimens appear to be the preferred methods of sample preparation. For samples that vary markedly in composition, the slope-ratio technique offers a new approach to solving matrix problems.
Use of Primary Filters in X-Ray Spectrography: A New Method for Trace Analysis*
Authors: Caticha-Ellis S. , Ramos Ariel , Saravia Luis
Published: March 2019

A method to improve the detectability of trace elements by X-ray fluorescent spectrography is described. The method consists of using appropriate filters in the primary, or exciting, beam. The effects of using filters in the primary beam on the peak-to-background ratio R of a fluorescent line have been analyzed on theoretical grounds. In fact,

where I1(λ0) is the intensity of the analytic fluorescent line, I1(λ0) is the background intensity due to coherent and Compton scattering of the primary radiation by the specimen, and I2 is the background intensity due to scattering of the fluorescent radiation by the analyzing crystal. Analytical expressions were derived for I1(λ0), I2, and I1(λ0), from which it has been concluded:

1.

The ratio I1(λ0)/I1(λ0) decreases when the filter used has its absorption edges at wavelengths longer than λ0.

2.

The ratio I2/I1(λ0) can be separated into two parts which vary in opposite ways. The influence of these two parts on the value of R is discussed in the text.

It is then shown that the method should work well at short wavelengths and less well at longer wavelengths. The method was tested in the difficult case where overlapping of the analytical line with a characteristic line of the tube occurred, i.e., in the determination of traces of selenium by using tungsten radiation. The analytic line Se Kα. has a wavelength of 1.106 Å, while W Lγ1occurs at 1.098 Å. There is a marked effect of the filter thickness on the detectability; an optimum thickness appears to exist for each case. In the analysis of selenium, the best filter thickness (which can be selected by mere inspection of the diagrams reproduced in the text) increased the detectability of selenium traces by an order of magnitude. Finally, from statistical considerations, the quantity tσ2 is proposed as an index of the effectiveness of the filter: the smaller tσ2 is, the better the filter is. Here σ is the standard deviation of the intensity of the analytic line and t is the total counting time spent on the measure of the analytic line arid background. In order to study the dependence of the index tσ2 on the filter thickness, measurements were made on samples of sugar containing known concentrations of strontium. Then tσ2 was plotted against the thickness of the filter for each concentration; these curves do show a minimum. Thus, an optimum filter thickness exists in each case.
Precision and Accuracy of Silicate Analyses by X-Ray Fluorescence
Authors: Baird A. K. , Welday E. E.
Published: March 2019

The relative merits of different methods of sample preparation, of different instrumental operating procedures, and of different calibration techniques for major and minor elemental analyses of silicates must be judged by adequate estimates of precision and accuracy. Sources of imprecision in the X-ray method include electronic deviations, counting statistics, and sample collection and preparation. The variations attributable to these sources set limiting values to any X-ray method. Because most X-ray methods are comparative and thus dependent upon standards, the accuracy is more difficult to establish. Sources of inaccuracy in calibration methods include biases introduced by instrumental design or operation, matrix and particle size effects reflected as scatter or calibration line curvature, and an inadequate knowledge of the chemistry of the standard or standards used. With an adequate estimate of the precision, a practical measure of the accuracy of the X-ray fluorescence method can be obtained by the predictions of the compositions of standard silicates—standards whose compositions are assumed to be established by repeated wet-chemical analyses. This practical approach to an assessment of errors suggests to us that the comparative X-ray methods are highly precise. Within the limits of precision and with appropriate standards, accurate predictions of the compositions of silicate rocks can be made without applying empirically or theoretically derived correction factors. In this paper tests of precision and accuracy will be described which have been used to assess variabilities in quantitative analysis from the sample collection, through the sample preparation, to the calibration with standards.
Applications of Computerized Statistical Techniques in Quantitative X-Ray Analysis
Authors: Mitchell Betty J.
Published: March 2019

The place of statistical techniques and the digital computer in analytical chemistry is clearly exemplified in the X-ray spectrograph laboratory. As the statistician is obsolete who uses only a desk calculator for his calculations in this era of rapidly changing technology and the need for increased productivity, so the X-ray man is severely handicapped who ignores the place of statistical techniques and associated digital computation in his work. For his calculations, the statistical X-ray analyst may choose from among the following: a small specialized computer designed as part of his X-ray equipment, a medium-size computer located in the laboratory building with the capacity to handle all the problems generated by the various analytical specialists, a time-sharing computer station which he shares with other analytical or testing sections of his main laboratory, or batch processing of his data by his company's computer center. Advanced types of desk calculators are now available which will permit rapid completion of some types of complex calculations, especially if they are set up in a systematic fashion. Careful study of an individual laboratory's problems will provide economic justification for the most appropriate type of computer calculation; the choice is dependent on many factors. This paper describes the advantages and disadvantages of the various computer systems for the X-ray spectrographer and the numerous statistical techniques which he may employ as an aid in hi? work. Statistics provide him with the tools to design his experiments, interpret his data, control the process which supplies his samples, improve sampling procedures, calibrate his X-ray equipment, perform theoretical studies, and calculate, correct, average, and evaluate his analyses. Digital computation provides him with an extraordinarily rapid means of making these calculations; in some cases, they are virtually impossible without computerization. Examples of analyses are described which are made practicable only by this combined statistical computerized approach. The accuracy and precision of computerized analyses are higher than for results obtained by the usual X-ray methods; analyst error is reduced to a minimum. The economics of present-day industrial life, especially applied to the analytical laboratory as a service organization, demand the most efficient possible operation of all analytical equipment. The X-ray laboratory presents an outstanding example of the need for statistical analysis and its associated digital-computer computation.
Production Control of Gold and Rhodium Plating Thickness on Very Small Samples by X-Ray Spectroscopy
Authors: Glade George H.
Published: March 2019

Manufacture of reed switches, critical components in present-day dataprocessing support devices, requires a means of accurate, rapid analysis of elements used in plating tlie levers of the switch. Because of gready reduced feedback time, X-ray spectroscopy has replaced metallographic sectioning and optical measurement as a plating-thickness control method. While 6 hr were required to obtain thickness data for a given sample size by sectioning, X-ray spectroscopy requires only 2 hr, which permits better control of the plating operating. X-ray spectroscopy is now used routinely to control both gold and rhodium plating thicknesses in the 20- to 100μin. (1 × 10−6) thickness range. The large number of samples prevents long count duration, while the small sample size (0.110 by 0.033 in.) reduces the precision of the analysis. However, the precision of the X-ray and optical methods is approximately the same, 8% variance. X-ray accuracy is comparable to that of sectioning since the standards are obtained by sectioning. Simplicity of operation is required since relatively untrained operators are used. An aperture system is used to reduce background. The rhodium thickness measurement is obtained from gross rhodium intensity. Attenuation of gross nickel intensity from the base material was found to be a better measure of gold thickness intensity. Calibration for hoth gold and rhodium is performed by using the same wide detector conditions. The choice of analysis is made by changing only the 2θ angle, thus avoiding the time required for recalibration when changing analysis.
The Influence of Sample Self-Absorption on Wavelength Shifts and Shape Changes in the Soft X-Ray Region: The Rare-Earth M Series
Authors: Fischer David W. , Baun William L.
Published: March 2019

The Mα and Mβ emission spectra and the Mjv and My absorption spectra have been studied for the entire series of rare-earth elements. It is conclusively shown that the complicated multiplet structure observed in the emission spectra is not real emission structure but is, instead, produced by sample self-absorption. This is demonstrated by observing the emission spectra over wide variations in take-off angle and bombarding electron energies and finally by comparing the detailed structure of both the emission and absorption spectra. The MIV and MV absorption structure completely overlaps the Mα and Mβ emission lines, which are each found to have but one intensity maximum when obtained under conditions of minimum. self-absorption. Some of these spectra have never been shown previously, while others have been studied in detail by several investigators. Points of agreement and disagreement with previous work are mentioned, and the wavelengths of the emission lines and absorption edges are listed for all of the rare-earth elements. It is concluded that the 4f → 3d electron transitions are reversible in these elements.
Quantitative Microprobe Analysis of Thin Insulating Films
Authors: Colby J. W.
Published: March 2019

The analysis of thin insulating films occurring in various stages of the manufacture of integrated circuits has in the past been difficult, if not impossible. Their dimensions usually preclude analysis by conventional chemical techniques, hence very little is known concerning their relative stoichiometrics. However, by microprobe analysis, films as thin as 540 Å (∼18μg/cm2) have been successfully analyzed. In general, two different approaches are taken, depending on the film thickness. Usually, films thicker than 2500 Å (∼50μg/cm2) are analyzed by conventional microprobe techniques. A computer program, called MAGIC, has been written, which converts the raw X-ray intensities to chemical composition. All data are corrected for dead time, background, absorption, atomic number effects, and fluorescence by characteristic radiation, if required. A minimum of input is required, only the chemical symbols. X-ray lines employed, and the accelerating voltage being necessary in addition to the raw X-ray intensities. All constants such as atomic weights, critical excitation potentials, X-ray wavelengths, and absorption coefficients are stored or calculated internally, which reduces the errors and time associated with looking up and key-punching these values. New fluorescent yields are used for K and L radiation. No fluorescence correction is made for M radiation. The use of this correction program generally gives results, accurate to about 2 to 4%, relative to the amount present. For films thinner than 2500 Å, a new model is proposed which allows the X-ray spectra from the film and substrate to be unfolded to give the composition of the film only. To accomplish this, the atomic number correction of Duncumb and deCasa employed in MAGIC has been used in conjunction with a mean electron energy concept. Results obtained to date through the use of this model have been surprisingly good, being of the order of 5% relative to the amount present. Potential errors and uncertainties are discussed, and results given which illustrate the accuracy of the two methods.
Study of Extended X-Ray Absorption Fine Structure with the Use of Thick Targets
Authors: Hach J. T. , White E. W.
Published: March 2019

A novel method has been investigated for the study of extended X-ray absorption-edge fine structures. The method takes advantage of the absorption of continuum X-rays that emerge at low takeoff angles from an electron-bombarded target. The extended fine structure is observed as undulations in the continuum X-ray intensity in the region of the self-absorption edge. Spectra from conventional X-ray diffraction tubes have been recorded for various values of kilovolts and takeoff angles. Spectra obtained by this method are compared with published data. Nearly all the features of the extended fine structures can be clearly resolved by this technique. In the case of iron ar.d copper targets, it is found, experimentally that the best contrast is obtained when using a 50-kV accelerating voltage. A takeoff angle of 3° yielded best results for copper, while an angle of 10° was best suited for iron. The Philibert absorption correction successfully used in electron microprobe analysis has been extended to account for the observed self-absorption effect where κΔλ = f(x)λ1/f(x)λ2. The primary advantage of the thick-target technique is in the ability to obtain absorption spectra without having to prepare thin films. The technique is essentially nondestructive in that the sample need not be pulverized or thinned.
Determination of Lattice Parameters by the Kossel and Divergent X-Ray Beam Techniques
Authors: Lutts A.
Published: March 2019

The principal aim of this article is to develop in a clear and orderly manner a general relationship and show how it can be used to determine with a high degree of precision lattice parameters of tetragonal and hexagonal as well as cubic crystals. The introduction and extensive use of electron-probe microanalyzers provides a ready-made means of obtaining both Kossel and divergent X-ray beam patterns which could previously be produced only with specially constructed X-ray tubes. The present ease of their production as well as the continuing need for precise lattice parameters for the study of many problems associated with crystallized solids has stimulated a renewed interest in these two techniques. As has been recently shown by several experimental results limited to cubic crystals, these techniques are capable of giving lattice parameters with the same degree of precision as those obtained by the more classical means. The development of the general relationship is preceded by a brief historical review, a discussion of the relative merits of the methods, a short description of the nature of the diffraction patterns, and the geometrical conditions necessary for realizing precision parameter measurements. In conclusion, the advantages and disadvantages of the Kossel and divergentbeam methods compared with those of the classical powder techniques are enumerated and discussed.
Measurement of Elastic Strains in Crystal Surfaces by X-Ray Diffraction Topography
Authors: Lawn Brian R.
Published: March 2019

The use of X-ray topographic techniques for studying elastic strains in crystals deformed at their surfaces is becoming widespread, especially in the field of silicon semiconductor devices. Although the broad features of the phenomenological processes involved in producing the strain patterns on the X-ray micrographs are understood, little attention has been devoted to evaluating the detailed nature or range of the strain fields in the crystal. In this paper, an clastic model is proposed for cases in which a region of crystal surface is uniformly deformed over a thin layer. With this model, the associated strain field in the surrounding crystal, which is readily computed from elasticity theory, may be characterized by a single parameter. The model is in accord with observed strain patterns on topographs of abraded diamond surfaces and silicon surfaces onto which a strip of metal film has been evaporated. From the spatial range of the diffraction contrast, an estimate of the parameter characterizing the strain field may be made.
Residual Stress and Shape Distortion in High-Strength Tool Steels
Authors: Gulbransen L. B. , Dhingra A. K.
Published: March 2019

One of the major problems that has plagued the tool and die maker for many years and more recently has come to the attention of the manufacturer of missiles and high-performance aircraft is the problem of shape distortion which occurs during heat treatment in the high-strength tool and die steels. Not only is shape distortion a problem in the heat treatment and use of these materials, but the origin of shape distortion has been a controversial issue among metallurgists for many years. The quantitative measurement of shape distortion on heat-treated steels is simply carried out hy machining standard shape samples, in this case, an L-shaped sample, and making a measurement of the variation after heat treatment from the 90° of the original 90° angle of the L. It is usually assumed that relief of residual stresses in heat-treated parts will occur by the shape changes which have been described above; however, it has been demonstrated that elastic residual stresses may still be present in heat-treated parts that have been tempered and theoretically should be stress free. By a very straightforward and simple application of the backreflection X-ray diffraction method for residual-stress determination, a very striking relationship has been demonstrated between the shape (angular) distortion of both A2 tool steel (air hardening) and O1 tool steel (oil hardening) and the residualstress pattern of these steels. Conversely, one could presumably utilize residualstress data at changes in cross section to estimate semiquantitatively the amount of shape distortion which occurs in rather complex parts.
Crystallite Orientation Analysis for Rolled Cubic Materials
Authors: Morris Peter R. , Heckler Alan J.
Published: March 2019

Roe's method for deriving the crystallite orientation distribution in a series of generalized spherical harmonics is applied to the analysis of texture in rolled cubic materials. The augmented Jacobi polynomials, which are the basis of the generalized spherical harmonics, have been derived for cubic crystallographic symmetry and orthotopic physical symmetry through the sixteenth order. Truncation of the series expansions at the sixteenth order should permit treatment of textures having a maximum of 17 times random and a minimum angular width at half maximum of 34°. A numerical technique has been developed which permits approximate evaluation of the integral equations from a finite array of data points. The method is illustrated for commercial steels and is used to elucidate the primary recrystalization texture of a decarburized Fe-3%Si alloy.
Influence of Sampling on the Quality of Analyses with Emphasis on Powders
Authors: Grant C. L. , Pelton P. A.
Published: March 2019

Sampling is a necessary part of the chemical analysis of particulate matter where the objective is to characterize bulk properties since it is usually undesirable or impossible to test an entire lot. The sample must be a miniature replica of the bulk material at least in respect to those features being tested. In other words, the sample must be representative to permit extrapolation from the sample to the bulk.

There is error associated with sampling particulate material, but this sampling error is only one component of the total error associated with an analytical result. Sample preparation and determination of the property being tested are two other major sources of error, These three errors combine as the squares of their standard deviations, i.e., their variances, to produce the total analytical error. Very often, sampling error is the largest of the three and, therefore, contributes a disproportionately large share to the total error.
A New X-Ray Diffraction Method for Quantitative Multicomponent Analysis
Authors: Chung Frank H.
Published: March 2019

A unified matrix-flushing theory and its practical applications for quantitative multicomponent analysis by X-ray diffraction are presented.

In this method, a fundamental “matrix-flushing” concept is introduced; the calibration curve procedure is shunted; the matrix (absorption) effect is totally eliminated; all components, crystalline or amorphous, can be determined.
High-Speed Retained Austenite Analysis with an Energy Dispersive X-Ray Diffraction Technique
Authors: Voskamp A. P.
Published: March 2019

A time saving method has been applied for the determination of retained austenite.

The method involved is based on the approach of energy dispersive X-ray diffraction analysis. With this approach, polychromatic radiation from the X-ray tube is used and diffraction maxima will occur at a fixed angle 2θ in as many wavelengths or energies as “d“ values are present.

Giessen and Gordon published the first application of this method to powder diffraction analysis in 1968 for the identification of crystal structures. As the determination of retained austenite is a quantitative type of analysis, based upon identification of the crystal structure, the new approach should also be applicable in principle.

With almost 100 samples of unknown austenite content, experiments have been carried out both with the conventional and the energy dispersive X-ray diffraction technique. The results obtained are closely comparable and the retained austenite values together with the errors are shown.

For these measurements, experiments have been carried out with the energy dispersive technique to determine the relation between the known concentration of retained austenite in a number of standards and the intensity correction factors (R). The results obtained from these experiments have shown good reproducibility of the intensity correction factors.

Using this technique, a five-fold reduction in analysis time is possible over the conventional technique with no reduction in accuracy.
Specimen Standards for X-Ray Spectrometric Analysis of Atmospheric Aerosols
Authors: Artz Bruce E. , Chessin Henry
Published: March 2019

Specimen standards have been prepared for elemental quantitative analysis of atmospheric aerosols by means of x-ray spectrometry. Efforts were made so that the standards were similar to the samples actually collected in the atmosphere. Soluable salts were placed in a completely enclosed, self-contained bubbler system so as to ensure uniform rate of flow through the filters on which elements were collected. The standards were deposited for various time intervals in the bubbler system and then weighed on a microbalance. Aerodynamic flow ensured that the specimens were uniformly distributed throughout the filter. Very satisfactory calibration curves were constructed of intensity versus mass of element. For low concentrations of the soluable salts and relatively small amounts of total material collected straight line relationships can be obtained for calibration curves. These amounts are mostly well within those actually collected in the field. The problem of impurity levels in collection filters which can far exceed the levels detected in the aerosols has been given careful consideration in the selection of filters used. Absorption-enhancement effects appear to be unimportant at the low concentration levels delt with. Interference problems with lead, arsenic, and bromine are discussed and appropriate calibration curves shown. A set of atmospheric specimens are analysed for several elements placing atmospheric aerosol analysis on a quantitative basis.
Use of Multiple Standards for Absorption Correction and Quantitation with Frieda
Authors: Ong P. S. , Cheng E. L. , Sroka G.
Published: March 2019

The computerized fluorescence radiation induced energy dispersive analyzer (FRIEDA) (1) described earlier uses an x-ray beam with a well defined energy for the excitation of fluorescence radiation, and an Si(Li) detector to measure the total x-ray spectra emitted. Such a system can also simultaneously provide supplemental data for the determination of the dry mass and the sample mass absorption which is necessary for accurate quantitation of the results. This instrumental capabillty has been utilized in the measurement of the trace elements iron, copper, and zinc in serum.

Known amounts of two elements are thoroughly mixed with the sample. One element has a ‘high energy’ K line, the other a ‘low energy’ K line. The ratio of these intensities, in the absence of absorption, is a known constant and dependent only on the relative amounts of the respective elements, and on the energy of the exciting radiation. Whenever absorption is present, the ratio will change in a manner directly related to the mass absorption of the sample for these radiations.
Chelating Ion Exchange Resins and X-Ray Fluorescence
Authors: Leyden Donald E.
Published: March 2019

Functional groups which form chelate compounds with metal ions have long been of analytical usefulness. Such compounds have served as titrants, precipitating reagents, extractants, and as ionogenic groups on ion exchange resins. These ion exchange resins often have high distribution coefficients which enable the quantitative extraction of metal ions from solution in a single batch treatment with the resin. This report describes the application of chelating resins to sampling and determination of certain trace metals using x-ray fluorescence. Two commercial resins will be discussed. Chelex- 100 (Bio Rad) is a resin containing iminodiacetic acid functional groups and has chelation chemistry quite similar to EDTA. NMRR (Srafion) is a resin containing a functional site selective for gold, platinum metals, mercuric ions and methyl mercury.
X-Ray Fluorescence Analysis of High-Temperature Super Alloys — Calibration and Standards
Authors: Heinrich K. F. J. , Rasberry S. D.
Published: March 2019

The current experimental work extends our calibration concept of separating the effects of absorption and fluorescence to the high - temperature superalloys. The new calibration procedure produces calibration equations which are valid over wide ranges of composition — a feature which is useful in the analysis of high - temperature superalloys . For the specimens considered, the elements iron, nickel, chromium, cobalt and molybdenum can be present at levels greater than 10%; while tantalum, aluminum, titanium, manganese, silicon and vanadium may be present at levels between 1 and 6%. The calibration for this group of alloys has required, in the past, a large number of standards; the number is reduced by judicious application of the given correction equations. Analytical errors can be limited to 1 to 2% in the use of this method.
Pole Figure Random Intensity Calculation Using Powder Integrated Ratios
Authors: Viana Carlos Sergio , Ferran Gustau
Published: March 2019

This paper describes a method for automatic quantitative pole figure plotting up to 70°, using only one sample and Schulz reflection technique. Random intensities are calculated for the usual planes of iron, using the ratios of calculated povder integrated intensities of these planes to the intensity of a high multiplicity factor plane, the random intensity of which had been obtained by integration up to 70° over the pole figure, using Bragg and Packer's method; the latter integration shows a decreasing error when the multiplicity factor increases. With this method it is possible to normalize the pole figures without using a physical standard and to reduce greatly the time to obtain a quantitative pole figure.
X-Ray Emission From Thin Film Materials
Authors: Stine P. A. , Hruska S. J. , Liedl G. L.
Published: March 2019

A theoretical model and experimental measurements of the X-ray emission from thin films generated by an electron beam were analyzed and compared. Ionization correction factors for the thin films and for substrate effects were developed to calculate intensity ratios of film and film on substrate to pure bulk intensities.

The fraction of electrons transmitted through gold, silver, and copper with energy greater than the critical excitation energy was measured as a function of thickness and primary electron energy. The characteristic X-ray intensities from gold on bismuth, palladium, nickel and aluminum Substrates; copper on palladium, nickel and aluminum substrates; and silver on aluminum substrates were measured and intensity ratios to pure bulk intensities were compared to the model prediction. The prediction of the X-ray intensity ratios were approximated by a simple electron balance model for the ionization correction factors and the consideration of electron energy distributions did not alter the predictions significantly.

An empirical conversion parameter, following the bulk procedures of Ziebold and Ogilvie, was determined experimentally for alloy thin films of gold and silver on oxidized silicon substrates for films between 500 and 2000 Å. The prediction of the parameter from the intensity model is in fair agreement with the measured values. However, the empirical conversion parameter could prove to be useful for thin film analysis.
A Combined Photoelectron/X-Ray Fluorescence Spectrometer
Authors: Herglotz H. K. , Lynch D. R.
Published: March 2019

Facilities for energy-dispersive x-ray fluorescence analysis have been added to an advanced version of the high-sensitivity ESCA (electron spectroscopy for chemical analysis) instrument described at the 1972 Denver Conference. Since the excitation mechanisms for electron emission and x-ray fluorescence are the same, the instrument's powerful source of primary x-rays is an asset to both types of spectroscopy. The geometrical arrangement of source, electron analyzer, and x-ray detector permits easy change from one mode of operation to the other without change of sample. While ESCA is valuable for the analysis of light elements and of surfaces apart from the bulk, x-ray fluorescence is useful for the analysis of bulk or substrate. The high excitation power makes the instrument useful also for trace analysis in solid or liquid samples. Modifications that could further enhance the usefulness of the instrument are described.
Diffraction Analysis of Liquid and Amorphous Alloys
Authors: Wagner C. N. J.
Published: March 2019

X-ray, neutron or electron diffraction patterns of alloys with structural disorder (micro-crystalline, amorphous or liquid alloys) consist of few diffuserings or halos. The ratio Ia(K)/ 2, where Ia(K) is the elastically scattered intensity per atom, K = 4πsinθ/λ, and  is average scattering factor of the alloy, is the sum of the Laue monotonic scattering ( - )/, the small angle scattering Is(K) and interference function I(K). For isotropic distribution of the atoms in the alloy, one can write:

and

where

ρ0is the average atomic density, V(r) is the size factor , ciand fiare the atomic concentration and atomic scattering factor of element i, respectively. Iij(K) is called the partial interference function which is related to the number ρij(r) = cjρ0gij(r) of j-type atoms per unit volume at the distancer from an i-type atom.

By varying the scattering factors of the elements through application of different radiations (x-rays, neutrons and electrons) and/or isotope enrichment, one can measure several I(K) which allow the evaluation of Iij(K) for a particular alloy. Assuming that gij(r) is independent of the relative abundance of the elements in the alloy , Iij(K) can also be obtained from several I(K) of the alloys with different concentratiora measured with a single radiation. This procedure has been applied to liquid Ag-Sn, Au-Sn and Cu-Sn alloys. The interference functions I(K), and their Fourier transforms, of vapor-quenched Ag-Ge and Ag-Cu films indicate that these alloys are micro polycrystalline with particle sizes of 15A in the Ag-52 at.% Cu alloy, 20A in the Ag-83 at.% Ge alloy and 24A in the Ag-64 at.% Ge alloy.