A review of the literature has shown that two major techniques are used to determine stress/strain in thin film structures: curvature measurement technique and internal stress measurement by the traditional sin2ψ technique. However, to date, there is no published comparison of the results from both techniques when they are applied to a given specimen.

In this paper we compare both methods theoretically and experimentally. We show that, while in some cases similar information is obtained from both techniques, there are cases where the two measurements give different results. We will show that, in such cases, the two methods can be complementary. Thus, they can be used to yield a more complete description of the total stress/strain tensor in the material.

A new approach to fundamental parameter calculations has been devised which makes use of incoherent and coherent backscatter intensities from the excitation radiation. The backscatter results from all sample constituents, and thus provides information on total sample mass as well as on bulk sample composition. By appropriately using the scatter intensities in fundamental parameter matrix calculations, accurate analyses of “unknown“ samples can be obtained without prior knowledge of the sample matrix. The backscatter with fundamental parameter (BFP) method is especially advantageous for biological, geological and environmental samples because of their bulk quantities of carbon, oxygen, and other light elements which cannot be explicitly determined for traditional fundamental parameter calculations.

The residual stress left on the fracture surface is one of the important parameters in X-ray fractography. It has been used to analyze fracture mechanisms in fracture toughness and fatigue tests especially of iron and steels.

In the present paper, X-ray fractography was applied to the brittle fracture surface of a silicon nitride ceramics. The first part deals with the determination of the stress constant for diffraction from Si3N4(411) plane by Cr-Kα radiation. The second part describes the effect of the notch-tip radius on the fracture toughness value. In the last part, the plastic zone depth was determined from the residual stress destribution beneath the fracture surface.

In this investigation we have examined how the full width at half maximum intensity (FWHM) and asymmetry of x-ray powder diffraction line profiles are influenced by the instrumental conditions adopted. Experimental x-ray data has been collected for a matrix of instrumental conditions by systematically varying the divergence slit angle (and the corresponding anti-scatter slit) over the range 0.25° to 1.25°, by using either a 0.05mm or 0.2mm receiving slit, or by removing the diffracted beam Soller slit. The line profile Standard Reference Material, SRM, 660 (LaB6) was used as the powder specimen in that it imparts minimal specimen induced broadening to the diffraction profiles. X-ray data were collected on a conventional, divergent beam, x-ray diffractometer using CuKα radiation.

The FWHM of the CuKα1 component can be as low as 0.035°2θ for high resolution conditions, but is normally ∼0.1°2θ at 2θ ≈ 30° for the instrumental conditions adopted in routine diffractometry. Below 2θ = 50°, the divergence slit has a significant effect on the FWHM and is the major cause of the increase in FWHM with decreasing 2θ. Results are presented of the 2θ dependence of FWHM values for each of the instrumental conditions recorded. A general relationship for the 2θ dependence of the FWHM and the asymmetry has been investigated to supersede the inappropriate Cagliotti expression frequently used in x-ray Rietvcld refinement.

The spray drying of powders is a method of forming spherical or torroidal shaped agglomerates. A relatively simple method is given for preparing spray dried samples of the quantities used in x-ray diffraction analysis. This technique is shown to minimize preferred orientation effects on diffraction intensities from materials of widely differing symmetry and crystallite habit.

An effective and practical computer algorithm has been developed for rapid and precise phase identification of polycrystalline materials by X-ray diffraction methods using the JCPDS database and/or user created standard files. The entire JCPDS file was reorganized for efficient search. Identifications are facilitated by a number of options: automatic correction of systematic errors using internal standard reflections, selectable window widths for file searching, elemental restrictions (chemical prescreening), handling preferred orientation, match without using intensities, match with 3 reflections, and others. A comprehensive algorithm for calculating a figure-of-merit (FOM) is used so that the “correct” phases can easily be identified with highest FOMs. This method has been tested extensively on a wide variety of analyses and is applicable to either a host or a minicomputer.

The interpretation and use of x-ray photon spectra of substances containing second row elements has utilized a number of theoretical models. These models may be divided into three basic categories, namely, the isolated atom model, various molecular models, and a number of solid state models, it is the purpose of this paper to examine critically the validity and limitations of molecular models for interpreting published x-ray photon spectra and spectra obtained by this group on chlorine and sulfur bearing substances.

Chlorine and sulfur bearing substances were chosen for at least three important reasons. First, a great deal of published experimental data already exists on the Kα, Kβ, and L2, 3 transitions of these substances. Second, motivated in part by the long standing controversy concerning possible 3d orbital participation in the bonding of second row elements, there are extensive quantum mechanical calculations for ions containing sulfur and chlorine via simple molecular orbital concepts. Thirdj the availability of accurate photoelectron spectroscopic data on these substances now permits a detailed quantitative comparison of x-ray photon transitions with quantum mechanical calculations.

Detailed evaluation along these lines indicates that for many substances the theoretically calculated energy values are frequently within a few electron volts (or less) of the experimentally observed energies. This study, therefore, tends to substantiate a viewpoint suggested by some recently; namely, that for many substances the starting point in interpreting most of the basic features of soft x-ray spectra should be based upon molecular bonding approaches.

The application of X-ray fluorescence-analysis methods to process control is discussed. Various methods of sample preparation are reviewed and compared. The use of the direct sampling technique is discussed and consideration is given to the effects of particle size on precision and accuracy of analytical results. The mechanism of these effects if presented, and some general principles concerning the relationship of fluorescent intensities and particle sizes of pure materials and mixtures are derived. Examples of particle-size effects in cement and mining applications are illustrated.

X -ray spectra arising from the valence bands of solids are useful for basic studies of the electronic structure of most materials and for practical measurements of unknowns to obtain information on local atomic structure and material properties as well as chemical composition. Understanding the characteristics of valence band spectra is prerequisite to their fullest use. One-electron and many-body aspects of the x-ray emission process, and the effects of experimental conditions, must be understood and are reviewed. Interpretation of spectral features and determination of electronic structure are complementary parts of one procedure which is based on the use of bonding theory. The various band and bond theories which are finding use for spectral interpretation are briefly reviewed. Calculation of the electronic structure of aluminum metal and quartz, and interpretation of their x-ray spectra, are examples which illustrate basic work with valence band spectra.

For determination of stress in a localized area, we combined a modified single exposure technique and the imaging plate, which is an x-ray digital area detector. With the, single exposure method, stress value is obtained from lattice strains in two directions with a single incident x-ray beam directed at an oblique angle. However, since diffraction data around a whole Debye-Scherrer ring was used in this study, a stress value can be accurately determined in comparison with the single exposure method. We observed the DS ring by use of the imaging plate with requiring only a short exposure time. Lattice strains in many directions on a DS ring were measured by an image analyzer connected to a computer; we verified the effectiveness of this method.

Usually, the classical Bragg-Brentano diffractometer arrangement is used for X-ray strain measurements. For measurements in different ψ-directions, the specimen is rotated clockwise or counter-clockwise around the diffractometer axis using a separate driving system (ω-diffractometer).During the measurements, primary and reflected X-ray beams are placed in the same plane as the normal of the specimen and the normals of the measured ﹛h,k,l﹜ -planes. However, the Bragg- Brentano principle also can he applied to strain measurements in different ψ-directions with a number of advantages if the specimen is rotated around an axis lying parallel to the diffractometer plane (ψ- diffractometer) (1). The principle, construction and characteristics of the ψ-diffractometer are described and compared with those of the ω-diffractometer.

The problems associated with quantitative determinations and descriptions of preferred orientation are discussed and a method proposed to yield quantitative descriptions. A means of obtaining representative quantitative data using reflection techniques is described. The position of intensity minima in quantitative pole figure descriptions of preferred orientation is equal in importance to intensity maxima. Hence, rate-meter counting of diffracted intensity as the sample is continuously or semicontinuously rotated in a given spatial relationship is not satisfactory. Instead, sealer counting by fixed counts at a given spatial position yields more meaningful results; however, fixed-time sealer counting is used to reduce the time for data collection. The data are plotted in the form of normalized pole figures and analyzed.

To determine the relative volume of material associated with a given-texture component and an index of preferred orientation, the data are integrated. This is done by numerical integration or, alternatively, by graphical means. Integrating over the interval from ϕ = 0 to ϕ = π/2 and α = 0 to α = n/2 (where ϕ and α are spherical coordinates) will give the pole concentration per unit area for an ideally randomly oriented specimen for an octant of the sphere of projection. The relative volume of material associated with a given set of intensity maxima can be determined by integrating the intensity over the area of the maxima, summing these values, and dividing by the multiplicity to obtain the total intensity, It. The relative volume can be expressed as a ratio of It divided by random intensity. The texture strength can be expressed as the standard deviation from the random condition. Such information is vital to quantitative predictions of the anisotropy of properties

An investigation has been made of the relative Kβ intensities in different chemical states of the sulfur atom using the Kα lines, with appropriate corrections, to provide the intensity standards. Both inorganic and organic compounds were included in the study. The data for each compound appear to be reliable to about ± 0.5%, while the whole series of compounds shows a variation greater than 20% in the corrected Kβ/Kα ratios. Energies were also measured, particularly the Kα energies, and their shifts were studied relative to the Kβ, intensity shifts. The work was done with a plane, single-crystal, helium-path spectrometer with proportional counter and pulse-height analysis for detection. The results are indicative of the usefulness of the method both in clarifying an uncertain chemical state and in studying the electronic structure of the bonded atom.

For the application of TXRF in trace element analysis, two characteristic features of the total reflection of X-rays are exploited. These are the high reflectivity on flat surfaces and the low penetration depth of the primary radiation. This allows the application of TXRF for both chemical trace and ultra-trace element analysis on the one hand and surface analysis on the other. For chemical trace clement analysis, total reflection on a highly polished substrate is characterized by a high reflectivity, which leads to a drastic reduction of the spectral background. The sample to be analyzed is prepared on the substrate as a residue of small quantities by evaporation from solutions or fine-grained suspensions. Instrumental detection limits of a few pg or sub-ng/ ml−1 arc state of the art for commercially available equipment. Besides the high detection power, internal standardization is another important feature of TXRF, enabling very simple quantification of the detected elements. The small sample mass required enables especially ultra-micro analytical questions to be tackled. For trace element analysis in surfaces the low penetration depth of the primary radiation under the conditions of total reflection is exploited. The penetration depth is in the range of a few nanometers, hence, TXRF is intrinsically surface sensitive. Detection limits better than 1010 atoms/cm2 are obtained for metal impurities on silicon wafers. For the examination of layered structures elemental composition, layer thickness, and density can be derived from die angle-dependent fluorescence intensities. The present paper describes the basic features of the total reflection of X-rays and gives some representative examples of the different uses of TXRF in trace element analysis.

Methods for, and results from, x-ray diffraction analysis of large numbers of fly ash samples obtained from U.S. power plants are described. Qualitative XRD indicates that low-calcium/Class F fly ash (usually derived from bituminous coal) consists typically of the crystalline phases quartz, mullite, hematite and magnetite in a matrix of aluminosilicate glass. Highcalcium fly ash (derived from low-rank coal) has a much more complex assemblage of crystalline phases that typically includes these four phases plus lime, periclase, anhydrite, alkali sulfates, tricalcium aluminate, dicalcium silicate, melilite, merwinlte and a sodalite-structure phase. Glass compositions among the particles are more heterogeneous and range from calcium aluminate to sodium calcium aluminosilicate, Every ash studied Is mixed with an internal Intensity standard (rutile) so that Intensity ratios can be used to make comparisons of the relative amounts of crystalline phases. An error analysis was performed to define the level of uncertainty in making these comparisons. These intensity ratios will be used for quantitative XRD phase analyses when reference intensity ratios for each fly ash phase become available.

Lead is a non-essential toxic metal of considerable topicality. It is accumulated in the skeleton, which contains 90% of the total body burden.

It is known that during the Roman period the intake of lead was high. The Romans used kitchen utensils made of lead and lead pipes for drinking water. The most important source of lead for people of the upper social classes was sapa, a compound added to wine to sweeten and perserve it.

Using non-destructive X-ray fluorescence analysis, lead and barium concentrations of archaeological Roman bones have been measured. We have earlier used a similar technique to determine lead concentration in the human skeleton in vivo.

This paper reports the results of a detailed X-ray diffraction study of a new phase-transformation observed in SiC crystals grown by a vapour-liquid-solid mechanism involving the hydrogen-reduction of methyltrichlorosilane. The 10.ℓ reciprocal lattice rows of these crystals, as recorded on X-ray diffraction photographs, reveal sharp reflections corresponding to the hexagonal close-packed 2H (ABAB….) structure and sometimes also corresponding to the cubic close-packed 3C (ABCABC…) structure. These reflections are invariably connected by a diffuse but continuous streak whose intensity is a measure of the random faulting on the basal planes. The crystals were needle shaped and the structure sometimes varied along their length.

Several crystals were annealed in an inert atmosphere at progressively higher temperatures and their 10.ℓ reciprocal lattice row re-examined to determine the annealing behaviour as well as possible structural transformations. For a number of dark green needles having a faulted 2H structure the 2H reflections disappeared around 1400° C and the 10.ℓ reciprocal lattice row revealed only a continuous streak with increased intensity around positions for 3C reflections. On further heating the structure went over to a strongly faulted 3C. Around 1600°C the appearance of a 6H structure became discernible while highly diffuse 30 reflections still persisted. The reversible part of the transformations, if any, could not be observed. Some of the structures were, however, found to be much more stable and did not transform even up to 1650° C.

The above results, in particular the discovery of a 2H-3C phase-transformation around 1400°C, throw fresh light on the thermodynamic stability of the different SiC types. The mechanism of the 2H-3C transformation, the possible influence of faults and impurities and the thermal stability of various SiC structures are discussed on the basis of the experimental results stated above.

Degraded detector pulses are shown to contribute most of the background in spectra produced by semiconductor-detector X-ray spectrometers. A new guard-ring detector is used with appropriate circuits to reduce background by a large factor. We discuss the sensitivity of the new arrangement with various excitation sources.

Investigation of the NiLIII band at various excitation voltages and the use of Ni and Ti thin films in the path of the NiLII,III and TiLII,III radiation, has shown that with proper electrode geometry and using target voltages of about 4 kv the effect of self absorption on emission edge shift and band shape is negligible for these elements. However, the LII/LIII intensity ratio of titanium is strongly effected by self absorption, but it is not effected for nickel and iron by self absorption.

A survey of several investigators’ soft x-ray band spectra from alloys and conducting compounds showed that the observed band changes were related to the electronegativity difference of the combining elements or the ionic character of the band. Peaks appearing on the low energy side of transition metal bands when combined with 2nd period elements appear to be a cross transition between the 2s or 2p band of the non-metal and inner level of the metal.

Over the last several years there has been growing interest directed toward high-resolution energy-dispersive x-ray detectors which operate at room temperature. The goal has been to develop a detector which combines the advantages of room-temperature operation characteristic of scintillation and proportional counters with the excellent energy resolution of silicon and germanium cryogenically cooled spectrometers. The elimination of the cryogenic coolant and the associated vacuum cryostat will permit the design and construction of really miniature and practically convenient x-ray detection systems which will find applications In already existing instruments as well as in various new fields.