The techniques of X-ray topography are reviewed, with special reference to their application to the study of surface layers and thin films. The methods of section topography, white radiation topography and double and triple crystal topography are shown to be the most appropriate, with grazing or glancing incidence methods assuming special importance. Applications to the questions of epilayer mismatch and dislocation content, process-induced defects and surface damage are discussed.

The sources of raw materials used in the manufacture of Portland cement include pure to argillaceous limestones, shale and clay, plus minor quantities of sand, iron ore, fly ash, coal ash and suitable industrial wastes. To ensure a high quality product, rapid - precise - reproducible and practical analytical techniques are required. Quantitative XRF analysis techniques meet those demands.

For this comparative technique, the instrument used is a wavelength dispersive sequential spectrometer. The advantages and the drawbacks of the technique are discussed, along with the procedure of the specimen fused bead preparation. The importance of calibration standards and unknown samples being prepared in an identical manner, and being presented to the instrument under similar conditions, is stressed. International and synthetic standards, concentration ranges for the five major elements, mathematically generated coefficients to correct absorption and enhancement effects, and a summary of the standard error of estimates are examined and discussed.

The accuracy of the method is verified by the analysis of known standard reference materials such as obsidian rock, coal fly ash, argillaceous limestone and blastfurnace slag. The values are compared with the known certified values.

One of the most difficult tasks in applied and residual stress measurement of polycrystalline materials using x-ray diffraction is dealing with preferred orientation and large grain size.

A common solution to large grain size problems has been to choose a larger aperture, but in certain cases this is undesirable and/or impossible. When preferred orientation has been identified as the problem, the common approach has been to choose another diffraction plane or oscillate the x-ray diffraction head during data collection. Remedies such as these can distort the peak breadth and are often not sufficient to totally negate the grain size and preferred orientation effects.

A technique described as the “step scan with virtual window” has been developed jointly at MTL (formerly Canmet) and Proto Mfg. Ltd. to deal specifically with the aforementioned effects of grain size and preferred orientation.

This paper highlights some of the problems that arise in stress analysis of materials exhibiting preferred orientation and large grain size. Subsequently a comparison of the results obtained using standard diffraction technique, oscillation and the “step scan with virtual window” is made.

52 elements of the periodic system are considered as potentially usable by living organisms. Most of them, as some heavy metals, are required only in trace amounts. If a certain concentration of a given trace element is exceeded in an organism it becomes toxic. Plant analyses are considered in agronomy as a diagnostic tool and as a guide to fertilizer practice as the plant uptake is the best criterion of nutrient and micronutrient availability. But nowadays also toxic metals may be assimilated by plants due to the increasing contamination by inorganic compounds containing these toxic elements. In geosciences plant analyses may be of importance because indicator plants are employed for the geochemical prospection of certain heavy metals.

We describe a new and reliable experimental technique for the measurement of mass absorption coefficients in the 0.1 to 1 keV energy range. In this technique, the absorbing film is supported directly on a substrate which under proton bombardment will generate the x-rays whose absorption will be measured. Results are given for thirteen different metals at the C Kα (277 eV) line.

The instrumentation and software for performing X-ray intensity measurements with a paper tape controlled diffractometer are described. The hardware includes two addressable axis positioners which control Slo-Syn stepping motors on the 2θ and ω) axes of the diffractometer, an addressable scaler-timer, a multiaxis programmer and a Teletype, in addition to the normal counting electronics. This system may be manually controlled with front panel switches or with instructions entered on the Teletype. In the automatic off-line mode instructions for motor speed, motor direction, starting angle, final angle, angular increment and scaler preset (time or counts) punched on paper tape are read and executed in sequence. A Teletype output of 2θ and ω angles, time and counts is obtained at each step. This off-line system was used for the measurement of austenite in H12 hot work die steel austenitized at various conditions and which contained a maximum of 13% austenite. A helium chamber was used to extend the limit of detection to 0.4% austenite. The X-ray analysis involved measuring the areas of the (200) austenite diffraction line and the (200) martensite line. For each of these lines, the system was programmed to integrate the counts over angular intervals corresponding to a low-angle background, the peak and a high-angle background using the ability of the axis positioner to stop the scaler-timer at the end of each angular interval. The additional capability of slewing rapidly between the various diffraction lines reduced the time required for automatic data collection. The present off-line system can be used to simplify other types of X-ray diffraction analysis such as residual stress and microstrain/particle size determinations, since the manual data handling can be eliminated with the computer compatible punched paper tape output. Future development of this instrumentation includes direct computer control of the diffractometer and computerized data reduction, with the advantage of a paper tape back-up system.

The use of a field portable XRF analyzer incorporating a semiconductor, mercuric iodide, energy dispersive spectrometer is described with emphasis on the benefits of high resolution x-ray detection for rapid screening of hazardous metallic wastes. Results are presented of “in-situ” and “prepared sample” soil measurement for different sites to show the potential of Fundamental Parameter analysis to obtain acceptable quality data with minimum calibration effort, obviating the need for site-specific standards.

X-ray fractography is a new method utilizing the X-ray diffraction technique to observe the fracture surface for the analysis of the micromechanisms and mechanics of fracture. The X-ray residual stress has been confirmed to be a particularly useful parameter when studying the fracture surfaces of high strength steels. The method has been applied to the fracture surface of fracture toughness and fatigue specimens.

Hematite (α-Fe2O3) powder compacts have been subjected to controlled, quantitative high pressure shock loading at peak pressures from 8-27 GPa and preserved for post shook analysis. The broadened x-ray diffraction peak profiles have been analyzed to determine the residual lattice strain and the coherent crystallite sizes. Maximum modification effects are observed near 17 GPa with strain values near 3 x 10-3 and size values near 200 Å suggesting annealing at higher shock pressure, resulting from the higher shock temperature.

As a means for quantitative texture analysis, the crystallite orientation distribution function analysis has an important drawback: to bring ghosts as a consequence of the presence of a non-trivial kernel which consists of the spherical harmonics of odd order terms. In the spherical hamonic analysis, ghosts occur in the particular orientations by symmetry operation from the real orientation in accordance with the symmetry of the harmonics of even orders. For recovery of the odd order harmonics, the 9th-order generalized spherical harmonics are linearly combined and added to the orientation distribution function reconstructed from pole figures to a composite function. The coefficients of the linear combination are optimized to minimize the sum of negative values in the composite function. Reproducibility was simulated by using artificial pole figures of single or multiple component textures. Elimination of the ghosts is accompanied by increase in the height of real peak in the composite function of a single preferred orientation. Relative fractions of both major and minor textural components are reproduced with satisfactory fidelity In the simulation for analysis of multi-component textures.

The first in vivo x-ray fluorescence measurements of lead in bone used y-rays from a 57Co source to excite Pb K x-rays. Later systems used γ-rays from 109Cd to excite Pb K x-rays or polarized x-rays to excite Pb L x-rays. All three approaches involve an extremely low effective dose to the subject. Of the two K x-ray techniques, 109Cd is more precise and more flexible in choice of measurement site. Pb L x-ray fluorescence (L-XRF) effectively samples lead at bone surfaces, whereas Pb K x-ray fluorescence (K-XRF) samples through the bulk of a bone. Both the polarized L-XRF and 109Cd K-XRF achieve similar precision.

Renal mercury has recently been determined using a polarized x-ray source. Both renal and hepatic cadmium can be measured using polarized x-rays in conjunction with a Si(Li) detector. Platinum and gold have been measured both by radioisotopic source excitation and by using polarized x-rays, but the latter is to be preferred.

Applications of Pb K-XRF have shown that measured bone lead relates strongly to cumulative lead exposure. Secondly, biological half lives of lead in different bone types have been estimated from limited longitudinal data sets and from some cross sectional surveys. Thirdly, the effect of hone lead as an endogenous source of lead has been demonstrated and it has been shown that a majority of circulating blood lead can be mobilized from bone, rather than deriving from new exposure, in some retired lead workers.

The efficiency of the recessed source geometry for the analysis of the content of wear metals in engine lubricant oils by Energy Dispersive X-Ray Fluorescence (EDXRF) methods is calculated by a Monte Carlo simulation considering X-ray detectors of the Gas Proportional Scintillation Counter type and excitation by Cd-109, Cm-244 and Fe-55 radioactive sources. Calculated spectra for the case of a typical aircraft oil with Cu, Fe, Cr, Ti, Sn and Ag impurities in the p.p.m. range were obtained and results are presented that allow the prediction of the counting rate per mCi and p.p.m. of the impurity content. The performance of the system is discussed concerning its potential applications to in-line monitoring of the wear metals.

Uniformity of particle size is most critical iti both X-ray spectrographic and diffraction samples. This is especially true when there are both hard and soft materials in the sample. The soft material reduces to a smaller particle size and therefore presents a great density and area to the X-ray beam. Accurate quantitative determinations are most difficult under these clrcum s tances. This paper decribes a means of grinding to a more uniform particle size and presents graphic data on the effects of particle-size variation.

The problem of background radiation in X-ray fluorescence trace element analysis of fused-glass iron ore samples is addressed. A first-order model of coherent and Comptcn scattering with primary absorption is presented and used to correct measurements. Overlap coefficients for elements in iron ores are presented. The importance of these corrections is demonstrated. The accuracy achieved with X-ray measurements after background corrections compares well with the accuracy of chemical analysis.

Ion implantation is known to increase the lifetime of cutting tools. Current theories are the increase in lifetime is caused by an increase in the residual stress, or by work hardening of the surface associated with the implantation. In this work the effect of ion implantation on the residual stress in titanium nitride coatings made by the standard industrial methods of chemical and physical vapor deposition (CVD and PVD) is studied. It is found in the as-received condition (unimplanted), the residual stress levels are near zero for CVD materials and highly compressive, of the order of 6 GPa, for PVD materials. Ion implantation has no effect on the residual stress: in the coatings made by CVD. Nitrogen does increase the compressive residual stress by some 10% in the near surface regions of PVD coatings, while nickel-titanium dual metal ion implantation does not have any effect. It appears that the lifetime increase is not associated with residual stress effects.

X-ray camera methods of stress measurement are inherently flexible and easy to apply in different situations because of the low weight, portability and maneuverability of the equipment. However, the digital intensity recording with the resulting objectivity and better statistical accuracy has given the diffractometer methods a distinct advantage over the conventional camera methods.

Although no revolutionary advance has been achieved in the last two decades, X-ray diffraction is not to be considered as a quiescent field of physics. Actually many improvements, in theory as well as in experiment, slight by themselves but very numerous, have considerably increased the efficiency of techniques such as the determination of crystal structures, the analysis of crystalline phases, and the applications of X-rays to various problems of the physics of solids. Only the two last points will be dealt with here:

1. 1. Crystalline phase analysis. The development of a satisfactory atlas of powder patterns has been too slow, and the data are not yet complete and precise enough to permit a rational utilization of the modern diffractometers. A very interesting new approach is the systematic indexing of the powder patterns which would be possible with computers. In the near future, anyone should be able to analyze a powder at any temperature as an easy routine experiment.

2. 2. The study of lattice defects. X-ray techniques are now in competition with electron microscopy, the development of which has been very successful in recent years. Now we have a better understanding of the possibilities of both techniques. X-rays give better results to determine the statistics of an extended disorder even if it is slight (e.g., degrees of order in a solid solution), and the microscope is more powerful for the detection of large but rare defects (e.g., dislocations).

Trace elements in oil may be determined by adsorption of the oil sample onto maguesium oxide followed by thermal degradation of the organic material. The resulting powder is easily pressed into a pellet suitable for X-ray spectrometric analysis. The lower limit of detection depends upon the trace impurities in the MgO and is a few parts per million for most elements determined.

At the present time there is considerable interest in the use of adhesive bonded joints for structural applications. The design of such joints is based mostly on finite element calculations and failure tests rather than on strain or stress measurements. To our knowledge no measurements have been made of stresses at or near the adhesive/adherend interface (where many bond failures occur) because of difficulties with accessibility. The purpose of this work was therefore to try to make such measurements using X-ray diffraction.

The approach taken was to gain access to the bond by making one of the adherends in a single lap joint to be relatively transparent to X-rays and the cither relatively opaque. Incident X-rays then penetrated the first adherend and the adhesive and were diffracted from gains in the second adherend adjacent to the adhesive/adherend interface. Stresses resulting from curing of the adhesive were determined first, after which a load was applied and the stresses redetermined.

Thin film samples represent ideal samples for analysis using X-ray fluorescence in that they tend to be flat, smooth and homogeneous. However, before a sample can be characterized using XRF, several questions must be answered.