In the current work an attempt was made to apply the fundamental parameter method to the analysis of boron, oxygen, fluorine and heavier components of silica glasses. Experimental results are presented and compared with calculations based on theoretical work. The specimens consist of sets of certified standards which were obtained from Breitlahder company, Germany.

Furthermore, it is shown that the match between the certified compositions and fundamental parameter computations is affected by the quality of available fundamental parameters for the ultralight elements as well as by the underlying mathematical models. Especially in quantitative analysis of these elements, a large variety of secondary enhancement effects must be taken into account. Two major mechanisms have been considered in the presented computations: excitation by fluorescence photons emitted from aiJ available excited atoms, and excitation by photoelectrons ejected after the primary ionization event. Their magnitude exceeds that of the conventional energy region by far and thus uncertainities in the corrective algorithms have a large effect,

The technique analysing the cause and mechanism of fracture from the information obtained by X-ray irradiation on the fractured surface is called “X-ray fractography.” As a basic study of X-ray fractography the residual stress on the fatigue fractured surface and some parameters of the fracture mechanics were investigated.

X-ray fractography is a new method utilizing the X-ray diffraction technique to observe the fracture surface for the analysis of the micro-mechanisms and mechanics of fracture.

In the present paper, X-ray fractography is applied to fracture surfaces of high strength aluminum alloy (JIS 7075-T6). The fracture toughness tests were conducted by using compact tension (CT) specimens with blunt notches and fatigue pre-cracks. The distribution of the residual stress near fracture surfaces was measured by the X-ray diffraction method. The effect of the notch radius on the fracture toughness value was discussed.

The present work was performed on natural monocrystals from Mexico. All crystals presented well-formed natural faces of indices (01.2), (01.4), (11.3), and (00.1). They were reduced to magnetite in a thermobalance by heating at 1200°C under a pressure of 10−3 torr. The techniques used in the present work were Laue reflection diagrams and pole figures. The magnetite formed on the hematite showed preferential orientations of three different types. The mutual orientations of the two oxides all present a common zone axis for the lattices formed by the oxygen ions.

Microwave dielectric ceramics with high quality have received attention due to the rapid progress in microwave telecommunication and satellite broadcasting. The desirable properties in microwave dielectric resonators are a high dielectric constant (εr), low dielectric loss (tanδ) (i.e. high Q (Q =1/tanδ)), and low temperature coefficient of the resonant frequency(τf). Properties of dielectric ceramics in the TiO2-rich region of the BaO-Nd2O3-TiO2 ternary system (Fig. 1) were reported to have excellent dielectric constants, low dielectric losses and low temperature coefficients of capacitance by Kolar et al. (1978).

The results reviewed in this article were obtained by means of the ESCA technique at the Institute of Physics, University of Uppsala, Uppsala, Sweden and at the Department of Physics, Vanderbilt University, Nashville, Tennessee, USA.

The ESCA technique is basically the study of induced emission of photo and Auger electrons from a sample irradiated with x-rays. If the incident radiation is monochromatic (e.g. an x-ray emission line) the spectrum of these electrons gives precise information about the energy states of the electrons in the sample. To extract this information, high resolution electron spectroscopy is necessary. Instruments for such spectroscopy have therefore been extensively developed during the last decade.

Using an X-ray diffractonieter cryostat, the lattice constants of the isotopes 20Ne and 22Ne as well as the naturally occurring mixture have been measured throughout most of the temperature range in which they exist as solids (0 to approximately 24°K), The heavier isotope has the smaller lattice constant, the values obtained at 4.2°K being: 20Ne—4.4624 Å, 22Ne—4.4540 Å, and 11Ne—4.4622 Å. The absolute error in these values is believed to be no greater than 0.001 A. The volume expansion coefficient, which does not appear to differ significantly in the three cases, increases to a value of 6.3 × 10−3/°K at 24°K.

During the past year the NORELCO Autrometer has been modified with respect to several details. Operation with the helium path and flow counter is now possible for work with the soft elements. Rotation in and out of the loading position is automatic so that all that an operator is required to do is to load the specimen holder. The sample or standard in the reading position can be rotated in its own plane for elimination of diffraction effects and other sample preparation problems. Other modifications in the electronics have increased the reliability and ease of maintenance in the production models, A description will be given of this latest unit and data will be presented on the results obtained both with respect to precision and analytical determinations.

In recent years, a number of experimental X-ray diffraction techniques have been developed by which a topographical display of the microscopical defects in a crystal can be obtained. This brief review of the most useful of these techniques is intended to summarize the elements of the various methods and to compare their respective features and limitations. Contrary to microradiographic methods, in which image contrast is due entirely to variations in X-ray absorption from point to point in the specimen, X-ray diffraction topography is concerned with point-topoint variations in the directions or the intensities of X-rays that have been diffracted by crystals. From these variations the defect structure of the crystal may be examined. Methods that mainly measure local variations in the direction of the diffracted beam are useful for the detection of gross misorientations such as subgrains or grains (methods of Gui nier and Tennevin, Schulz, Weissmann). Intensity mapping methods are chiefly concerned with individual defects such as dislocations, stacking faults, etc. In both groups there are experimental arrangements with both Laue-case (transmission) and Bragg-case (back reflection) geometry.

Standards for microprobe analysis can be made to serve two purposes: (a) proposed correction models can be tested with them, and (b) analysis can be performed more accurately in the system which includes the standard. Few microprobe standards presently are available because they must be homogeneous on the micron scale and their composition must be known accurately. A modified Duwez splat cooling method is described which enables the investigator to prepare suitable standards in most cases. The apparatus which is relatively simple and inexpensive is described in detail. The systems Au-Si and Al-Mg were chosen as test cases. Suitable standards were prepared at different concentrations in each system. The analytical results for all compositions in Al-Mg are presented and discussed.

The angular dependent factors which affect the intensities of X-ray diffraction line profiles, as observed on a Standard X-ray diffractometer, are well established. They are the Lorentz factor, the polarization factor, the atomic scattering factor, and the temperature factor. For residual stress analysis, in which measurements are made at non-zero omega (psi) angles, an absorption factor must be added to this list. It is usual, however, in residual stress analysis, to omit two of these factors: the atomic scattering factor and the temperature factor. The omission of these two factors appreciably alters the change in the combined correction factor with change of diffraction angle. The proper angular dependent corrections are in the opposite sense to those customarily employed. The effect of the additional factors on measurements of residual stress are discussed.

This is an introductory review of the physics and applications of low energy x-rays and electrons in the 10-1000 ev region. The basic interactions of these radiations within matter are discussed and typical de-excitation spectra, fluorescent x-ray and photoAuger electron, are presented. Specific examples of spectrographic methods and instruments for the low energy region are described as “based upon the use of long-spaced, Langmuir-Blodgett type of multilayers for ultrasoft x-ray analysis and the use of the hemispherical electrostatic analyzer for photo-Auger electron spectroscopy. Some examples of spectrographic signal, signal/background, and resolution are presented for applications to light element fluorescence, valence emission band, and photo-Auger electron analysis. The special aspects of the low energy x-ray analysis of high temperature plasmas and of x-ray astronomical sources in general are described.

Traditionally, aluminum has been the most important raw metal material for the aerospace industry. Since the major part of aluminum production is consumed for aircraft, military, space, and other programs, sponsored or regulated by the U. S. Government, quality of various Al alloys is under governmental control. The representatives of the governmental agency are placed at each aluminum plant in order to assure a high quality of production on-site. A fast and reliable analytical method is essential to control the production process and to keep chemical composition of the alloys inside specified ranges.

An array of molecules that is anisotropic in the extreme has been discovered in certain thermal-energy storage materials and is reported here: neopentylglycol (NPG) and NPG-rich solid solutions with pentaglycerine (PG) have a crystal structure, stable at room temperature, that consists of bimolecular chains of molecules that are all unidirectionally aligned throughout a crystal. There are hydrogen bonds between every molecule in one chain and its neighbors in that chain, but none between molecules of one chain and any molecules of the neighboring parallel chains. Thus there are strong intermolecular bonds along each chain and only weaker bonds between the chains. The structure has been determined by using modern single crystal techniques with 529 independent reflections from a crystal of NPG (C5H12O2). The structure is monoclinic with space group P21/c - C2h5. This anisotropic structure transforms to a cubic structure at higher temperatures.

Occupational exposure to lead is common in many industrial applications and hence it is of considerable medical interest to control the body-burden of lead in living man. More than 90 % of the lead in the body is concentrated in bone and hence in vivo measurements of the lead in the skeleton should give the most satisfactory way for estimating the body-burden. The routine method used today for checking on lead contamination is that of measurements on blood samples. However, since the concentration of lead in the blood is a sensitive function of the actual exposure conditions, this method provides only a poor indication of the total body-burden and the integrated lead exposure.

The feasibility of utilizing the Inverse Monte Carlo (IMC) method to determine elemental amounts in homogeneous samples from energy-dispersive X-ray fluorescence (EDXRF) measurements has been investigated. IMC is a novel application of standard Monte Carlo that, in principle, allows a rather large class of inverse problems to be solved noniteratively, in the sense that the simulation is not repeated. IMC is implemented by hypothesizing values for the unknown parameters, executing a direct Monte Carlo simulation using these values and scoring the results with factors that contain the unknown parameters. By equating the resulting Monte Carlo estimators to the known measured responses, a system of algebraic equations is formed that may be soluble by standard numerical techniques. Advantages of IMC include the facts that it can be applied to complex (e.g., multidimensional) problems and that it is relatively efficient since the simulation is performed only once. In the EDXRF case, simplified assumptions have been used to construct an approximate IMC solution. The model provides a means to determine the elemental amounts in an unknown sample by treating the unknown composition as a perturbation around the composition of a fixed "reference" sample that contains the same elements as the unknown sample. Primary and secondary X-rays are included in the model. The resulting system of algebraic equations is nonlinear and solutions are obtained via an approximation. Since the model is based on correlated sampling techniques, several unknown samples can be modeled simultaneously provided that they contain the same elements and their compositions are sufficiently close to that of the assumed reference sample. Direct Monte Carlo was used to generate the relative intensities for eighteen different samples in a ternary (Ni-Fe-Cr) system; these results were then used in the IMC model to recover the sample weight fractions. Excellent results were obtained, demonstrating the feasibility of the approach.

Li et al (1990) reported experiments with gibbsite powder specimens on the use of Rietveld pattern-fitting, involving the March preferred orientation model, to characterise preferred orientation according to the March r parameter. It was shown that intensity corrections may be applied with the March r parameter derived from Rietveld analysis or with the related line intensity ratio MR which is sensitive to preferred orientation. The present paper reports an analytic expression involving r and MR which has proved highly reliable for the correction of preferred orientation bias in quantitative phase analysis of gibbsite. Similar expressions may be readily derived for other materials for which the March model is appropriate. Therefore the line ratio approach has considerable potential for rapid correction of intensities for preferred orientation.

Synchrotron radiation (SR) has several unique properties which cause it to be used for many purposes in science and technology. It is continuous spectrally, collimated spatially, short-pulsed yet continuously-operating temporally, as well as polarized( 1). Many applications of SR have already been demonstrated. These range from production of fine scale structures by lithography to numerous studies of materials. Determination of atomic structure by diffraction and other scattering experiments and by absorption spectroscopy (EXAFS), and emission spectroscopic studies of electronic structure have been given most attention(2). Only limited attention has been paid to determination of materials composition by x-ray fluorescence analysis (XRF) employing synchrotron radiation. Sparks et al.(3-5) have performed the most notable experiments, examining mica inclusions for the presence of primordial super heavy elements and irradiating two National Bureau of Standards Standard Reference Materials (SRM 1571, Orchard Leaves and SRM 1632, Coal) to measure the fluorescent x—ray intensity from the trace elements.

The effect of temperature on nucleation and growth of Ti3Al precipitates in two Ti-Al alloys was determined using sensitive X-ray diffraction techniques. The X-ray peaks arising from the ordered Ti3Al phase were compared with the fundamental peaks of the matrix. Peak broadening due to particle size resulted from the small Ti3Al precipitates and this was analysed using Fourier methods to determine a mean particle size and particle size distribution. The two alloys used for this investigation were Ti-8.5 wt.% Al and Ti-8%Al-1%Mo-1%V (8-1-1) alloy. The precipitate size in Ti-8.5 wt% Al was considerably more dependent on temperature than the precipitate size in 8-1-1 alloy, achieving a size of 190Å after 20 hrs at 650°C. The solvus temperature for precipitation was the same for both alloys, vis, 675°C to 700°C. These results compare favorably with transmission electron microscopy of thin foils prepared from the same samples.

The Fourier analysis of the broadened profiles in a powder pattern allows the determination of the effective particle or domain size and the microstrains within each domain in polycrystalline materials. In order to apply this method to the diffraction patterns of thin films and coatings, deposited on crystalline or amorphous substrates, special diffraction techniques must be employed for the registration of the relatively weak intensities. The fitting of the experimental profiles to pseudo-Voigt functions permits the recovery of the peak tails and a precise determination of the background. The positions of the peak maxima or centroids yield information about any compositional variations, and about the occurrence of stacking faults and residual stresses in thin films and coatings.