bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractA 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

SummaryA 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

AbstractSpecimen 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

AbstractThe 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

AbstractFunctional 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

AbstractThe 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

AbstractThis 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

AbstractA 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

AbstractFacilities 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

AbstractX-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)/<f> 2, where Ia(K) is the elastically scattered intensity per atom, K = 4πsinθ/λ, and <f> is average scattering factor of the alloy, is the sum of the Laue monotonic scattering (<f2> - <f2>)/<f2>, the small angle scattering Is(K) and interference function I(K). For isotropic distribution of the atoms in the alloy, one can write:andwhereρ0is 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.
Instantaneous Display of X-Ray Diffraction using a Diode Array Camera Tube
Authors: Chester Arthur N. , Koch Fred B. 
Published: March 2019

AbstractThe silicon diode array camera tube, recently developed for PICTURFPHONE® service, was modified to permit X-ray imaging. High quantum efficiency is attained without the use of a phosphor screen, since each photon absorbed in the silicon target generates several hundred hole-electron pairs for each keV of its energy, most of which can he usefully collected. The sensitivity and resolution are adequate to allow a continuous television display of the diffracted intensity as a crystal is oriented. Particular advantages of this technique include; high resolution (< 25 μm); electronically variable magnification; direct oscilloscope measurement of X-ray spot Intensity profiles and relative spot intensities because signal current is directly proportional to photon flux; high sensitivity in the range of 0.6 to 5.0 Å, potentially limited only "by counting statistics; integration times variable from < 1/60 second to minutes; and expected low cost, since the camera tube has no complicated electron imaging, and is directly interchangeable Mith a standard television vidicon. Applications which are described include crystal orientation and X-ray topography.
An X-Ray Lime Shape Study of HP 9-4-45 Bainites and Martensites
Authors: Klems George J. , Pascover J. Stephen 
Published: March 2019

AbstractThe broadening of the (110)α and (220)α powder pattern peaks of bulk samples from the product of two commercial 70 ton heats of a 9Ni-4Co-0.45C alloy (HP 9-4-45) was studied by Fourier analysis. Both heats were heat treated to a variety of bainitic and tempered martensitic structures and the effective particle size and r.m.s. strain in the <110> direction were measured. Comparison of the mechanical properties with the parameters derived from the Fourier analysis suggests that neither the strain nor the particle size are controlling the strength or toughness. Strength increases with Strain while toughness decreases - both as expected. On the other hand, large particle size seems to favor greater toughness in contrast to the known effect of macroscopic (high angle boundary) grain size.It is concluded that line shape analysis is a convenient method of investigation giving repeatable parameters which represent the transformation strains. The extension of this technique to these highly strained, metallurgically complex structures appears justified.
Homogeneity Characterization of NBS Spectrometric Standards IV: Preparation and Microprobe Characterization of W-20% Mo Alloy Fabricated by Powder Metallurgical Methods
Authors: Yakowitz H. , Michaelis R. E. , Vieth D. L. 
Published: March 2019

AbstractA significant problem of the National Bureau of Standards Standard Reference Materials program is the provision of standards suitable in homogeneity for use with microanalytical techniques such as the spark source mass spectrograph and the electron probe microanalyser. An interim approach to the problem has been the extended homogeneity characterization of selected existing standards. This paper describes the preparation and evaluation of the first NBS standard tested specifically from the beginning for application to electron probe microanalysers. The standard designated SRM 480 is a tungsten-20 weight percent molybdenum alloy prepared by a powder metallurgy process. Based on the results of about 1500 determinations for both tungsten and molybdenum by electron probe microanalysis, the material was found to be of high homogeneity at about the micrometer leve 1 of spatial re so lution. The coefficient of variation for molybdenum was 2.5% and that for tungsten 1.5%. Correction of relative intensity ratios to obtain concentrations is discussed in terms of input parameter uncertainties such as mass absorption coefficients, and electron backscatter factors. The result of studies for atomic number correction and effects on operating voltage on the microprobe absorption correction, will be given. It is concluded that SRM 480 should be a valuable addition to any microprobe laboratory doing quantitative analyses.
A Rapid and Accurate X-Ray Determination of the Rare Earths Elements in Solid or Liquid Materials using the Double Dilution Method
Authors: Tertian R. 
Published: March 2019

AbstractThe double dilution method has many important advantages. For any element to be determined, let us say A, It enables us to control or calculate the matrix factor (sum of the absorption end enhancement effects) for the sample being Investigated towards A radiation, and it furnishes corrected Intensities which are strictly proportional to A concentration. Thus the results are exact, whatever the general composition of the sample, their accuracy depending only on the quality of measurement and preparation. Another major practical advantage is that the method does not require systematic calibration but only a few permanent standards consisting of a pure compound or of an accurately known sample.The procedure has been tested successfully for accurate determination of rare earth elements using, for solid materials such as ores and oxide mixtures, the borax fusion technique. It also can be readily applied to liquids. All the rare earth elements can be titrated by that method, as well as yttrium, thorium and, if necessary, all the elements relevant to X-ray fluorescence analysis. The concentration range considered for solids is of one comprised between 0.5 and 100 % and, with a lesser accuracy, between 0.1 and 0-5 % Examples are given relative to the analysis of various ores. Finally it rcust be pointed out that the method is universal and applies to the analysis of every solid, especially ores, provided that they can be converted to solid or liquid solutions. It appears that most industrial analyses can be worked on In this way.
Mass Absorption Coefficients and Quantitative Microanalysis of Refractory Metal Carbides
Authors: Gray Lawrence J. , Wert C. A. 
Published: March 2019

AbstractConsideration of variations in atomic potentials permits an estimation of the mass absorption coefficients of many elements for the characteristic emission lines of carbon, nitrogen and oxygen. The accuracy of (μ/p) values presented is better than 5% in most cases. These values are tested in the microanalysis of defect titanium carbides. Limitations of the theoretical correction procedures lead to the definition, of a set of analysis conditions which permit carbon analysis to within 1.0% absolute.
Determination of Argon in RF Sputtered SiO2 by X-Ray Emission
Authors: Lloyd J. Charles 
Published: March 2019

AbstractArgon is commonly used as the sputtering medium for RF sputtering of insulators and is entrapped in the deposits. X-ray emission determination of argon in RF sputtered SiO2 was required as part of a study of the relationships between argon concentration in the deposits and their electrical and physical properties.Concentrations ranging from 0.05 to 7.4 weight % argon were measured in deposits 0.5 to 5μ thick. Two techniques were used for standardization: (1) weight loss of deposits heated for several hours in a helium atmosphere at 600°C; (2) potassium Kα and chlorine Kα measurements on a KCl film of known thickness to infer argon mass/argon Kα net counts. Calibrations made using these procedures agreed to within 10% and are reliable to about ±25% on an absolute basis. Absorption of radiation by the deposits was taken into account and used to correct measured argon intensities for absorption.Sputtering parameters which had major effects on argon concentration were the substrate temperature and the magnetic field applied during sputtering. Argon pressure and RF power were found to have lesser effects.
Rapid Determination of Ash in Coal by Compton Scattering, Ca, and Fe X-Ray Fluorescence
Authors: Renault Jacques 
Published: March 2019

AbstractThe intensity of Compton scattering, Fe, and Ca chatacteristic radiation can be used to estimate the amount of ash in coal by Xray fluorescence spectroscopy. Mo, W, and Cr radiation were used to study a suite of New Mexico coals, and the best results were obtained with Mo and W X-ray tubes. If the actual concentrations of Fe2O3 and CaO and the mass absorption coefficient, μ*, at the Compton wavelength of scattered Mo K radiation can be determined, the regression equation:%Ash - 24.2μ* - 6.28(%Fe2O3) - 1.96(%CaO) - 3.4estimates the ash content with an average error of 0.5% ash at 0.71Å.
Energy Dispersive XRF Composition Profiling Using Crystal Collimated Incident Radiation
Authors: Boettinger W. J. , Burdette H. E. , Kuriyama M. 
Published: March 2019

AbstractIn order to measure changes in composition as a function of distance (macrosegregation) in directionally solidified two phase samples, a well collimated incident x-ray beam is required for XRF analysis. This is accomplished using Bragg diffraction of AgKα radiation from a highly perfect Si crystal. Because the incident beam is also monochromatic, additional advantages are realized: a) the backgrounds caused by Compton and thermal diffuse scattering (TDS) of the incident beam are well localized in the energy spectrum and do not interfere with the fluorescent peaks, b) the TDS can be used as a monitor of the incident photon flux and hence eliminates often substantial errors caused by incident beam intensity fluctuations.Using several prepared standards, the ratio of PbL counts to TDS counts was found to be a function of the total Pb content of the two phase microstructure, with a reproducibility determined only by counting statistics. Furthermore, the function was found to be nearly linear over a wide range of compositions. Standard methods of absorption or enhancement correction can be employed using this ratio. The spatial resolution, determined by profiling a sharp discontinuity between two metals, was 0.5 mm.Macrosegregation data is presented for Pb-Sn two phase alloys whose compositions range from 35 wt % Pb to 70wt % Pb. Comparison of compositions with those determined by a titration method agrees to within 2 wt % for most of the metallurgical structures present in the work. Somewhat larger deviations were found for samples with high Pb contents with extremely coarse two phase microstructures.