The principles and techniques for performing coating thickness measurements in the laboratory and on-line using nuclear radiation have been established for tin or zinc coated steels. Recently, additional engineering efforts have been made toward the development of new coating substances consisting of complex layered materials. For example, zinc-iron alloy metal has higher corrosion resistance than pure zinc-coated steel sheets and evaluations have been made of beneficial characteristics in automobile production processes, such as easy welding, good paintability, high efficiency for press plastics forming, etc.

The mass absorption coefficient is perhaps the most under-utilized parameter in x-ray diffraction analysis. Mass absorption measurements are often avoided in quantitative analysis by resorting to calibration curves of internal standards (e.g., Kung and Alexander, 1974, Sec. 7-2.1). However, Leroux et al. (1953) and Frevel and Roth (1982) directly utilized the mass absorption coefficient in multicomponent analysis, and suggested a "substrate diffraction" procedure for directly measuring the sample mass absorption coefficient. The reference intensity procedure of quantitative multicomponent analysis originally formulated by Frank Chung (1974) requires no explicit use of the mass absorption coefficient because all reference intensity ratios are determined relative to an "external" standard, generally corundum (Al2O3).

Multilayers composed of many thin films of PbTe and Pb1-xSnxTe on BaF2 substrates were grown epitaxially by hot-wall-vapor deposition. In order to investigate the fraction of the total misfit (2.5x10-3 at x=O, 12) accommodated by misfit strain we have performed strain measurements on these superlattices by two different X-ray diffractometer techniques. We also report on substrate induced strain due to different thermal expansion coefficients of films and substrate. For film thicknesses smaller than 300 nm there is clear evidence for almost complete accommodation of lattice mismatch by misfit strain. Below room temperature the substrate induces a tensile strain which is comparable to that of the misfit strain.

Preferred orientation has long been considered the primary source of systematic error involved in quantitative analysis by X-ray powder diffraction. Techniques of spherical agglomeration have been shown to eliminate preferred orientation provided that the agglomerate size is made sufficiently larger than the particle size. These techniques invariably employ the surface energy minimization of a liquid phase dispersed within a second fluid to create the spherical form desired. Spray drying has been the only method to date which has been successfully used to prepare spherical agglomerates suitable for X-ray diffraction. This study was undertaken to investigate possible deleterious effects of spray drying as a diffraction sample preparation technique.

The characterization of multi-layer thin films by X-ray fluorescence using the fundamental parameter method and the LAMA-III program is described. Analyses of a double-layer FeMn/NiFe and two triple-layer NiFe/Cu/Cr and Cr/Cu/NiFe specimens show that the complex inter-layer absorption and secondary fluorescence effects were properly corrected. The compositions and thicknesses of all layers agreed to ±2% with corresponding single-layer films, a precisian comparable with bulk and single-layer thin film analyses.

Spray drying is shown to be an effective and rapid method for preparing samples for quantitative analysis by x-ray powder diffraction. Previously intractable problems like the simultaneous analysis of multiple phases in orientation prone systems can be carried out. Using this method, and a computer controlled diffractometer, five and six phase analyses of Devonian shales can be accomplished in approximately forty minutes. A rapid and convenient method for using the absorption diffraction technique for x-ray quantitative analysis is described.

We have developed a technique to determine the dissolved solid components of water and other liquids by Energy- Dispersive X-Ray Fluorescence (EDXRF) spectrometry. The liquid samples are presented to the spectrometer as small dried spots of the residue remaining after evaporation of the liquid. The dried residues are mounted on thin plastic films cemented to 35 mm plastic slide mounts. Elements from sodium through uranium are detected with detection limits less than one nanogram in favorable cases. Precision of the measurement is better than 2 % relative in favorable cases for secondary-target excitation, and is typically 5 to 10 % for direct excitation given the geometry of the instrument. Detection limits are as low as a part per billion relative to the original liquid for solutions whose total dissolved solid content is 1000 part per million or less.

The peak angle 2θp is one of the most commonly measured parameters in powder diffractometry, but there is little understanding of the extent to which the instrument affects this measurement. The majority of theoretical and experimental studies of the effects of instrumental aberrations have been based on the peak centroid 29c. In this investigation we have examined the extent to which peak angles in a conventional powder diffractometer shift for different combinations of divergence slit, Soller slits and receiving slit. The line profile standard SRM 660 (LaB6) was used to generate instrument profiles and X-ray data were collected from a diffractometer fitted with a fine focus Cu X-ray tube and a graphite post-monochromator set for CuKa. The effect of the instrument is greatest at low angles, but shifts arising from axial divergence can also be detected above 2θ=120°. Below 2θ = 40° changing the divergence slits from 0.3° to 1.0°, or removing one of the Soller slits, can move 2θp by up to 0.025°.

Calibration procedures and data are presented for plating thickness measurements of gold, silver, tin, and nickel on copper, brass, and steel basis metals. Both emission and absorption techniques are described, and examples are given of measurements on thicknesses from 10 to 600 millionths of an inch. The use is shown of masking and integrating techniques for curved or unusual shapes.

For the special problem of duplex platings, which have two metals each varying in thickness, the Kα/Kβ absorption ratio and the Lα/Lβ emission ratio are compared with conventional absorption and emission techniques.

Optical and chemical determinations are shown to be less precise as well as considerably slower than X-ray measurements on the same piece. Examples are given of the use of X-ray measurements to study fundamentals of plating processes, such as barrel-plating thickness distributions and variation of thickness across a surface, as well as to study processes such as wear or porosity.

Pure cobalt and cobalt-nickel alloys have been plated from simple electrolytic baths with and without additive and with and without ac superimposed upon the dc plating current.

X-ray analysis reveals preferred orientation in the polycrystalline deposits generally and extreme preferred orientation (characterized by [00.2] and [11.0] fiber axes) in the case of those samples obtained with additive-free electrolyte. It is shown that a change in the pH of the bath or the addition of an ac component are equally effective in determining the type of fiber axis in the deposit. The effects on plating texture owing to the use of additive KCNS in the bath are described. Finally, the correlation between the texture and the magnetic properties of the plating Is discussed.

In X-ray diffraction and wavelength dispersive X-ray fluorescence, it is necessary to determine the intensity of a coherently diffracted X-ray peak with respect to its position, two-theta. To accomplish this, most X-ray diffractometers are provided with a scanning goniometer mounted X-ray detector that scans the angular two-theta region of interest and obtains X-ray Intensity as a function of time and therefore two-theta.

By utilizing the total reflecting properties of x-rays inside glass capillary tubes, intensive fine- or microbeams of x-rays can be attained. By using a conventional x-ray tube in combination with capillary technique, microbeams with a diameter of a few μm and with an intensity sufficient for trace elements, analyses have been achieved. By moving the sample, lineand areascan can be performed and trace element information can be directly superimposed on a micrograph from a built-in optical microscope.

The background of the capillary technique is reviewed and an EDXRF microbeam spectrometer for trace elements is described. Examples of applications for the microbeam spectrometer are given.

Impurity-doped crystals CdS(GaGl3) have been studied by X-ray topography. Some large precipitates are formed close to the crystal surfaces by annealing at 300°C. In the symmetrical Laue case, the precipitates show circular images (30-60 μ in diameter) due to the radial strains around the precipitates which consist of two semicircles separated by a contrast-free plane parallel to the reflecting plane. The observations indicate that the strain field between the crystal surface and precipitate is not responsible for the contrast, and that the images are formed by X-rays which are deviated from the Bragg condition for the perfect region and satisfy the Bragg condition in the strain field on the inside of the precipitate. One of the semicircles is formed by the incident X-rays with larger glancing angles than the Bragg angle and the other with smaller ones. It is concluded that this contrast is due to the strain around a convex lens shaped precipitate.

The system to be described includes hardware and software for the on-line computer control of the X-ray diffraction measurement of residual stress. This determination involves accurately measuring the angles at which a back-reflection line is diffracted, first by diffracting planes parallel to the sample surface, and then by planes at an angle (ψ) to the sample surface. The residual stress is calculated from the difference in the two measured diffraetion angles. The procedure executed by the computer consists of locating the peaks, selecting three angles for collection of X-ray counts, correcting the measured counts, fitting the equi-angular intensity measurements to a three-point parabola, calculating the peak angles, calculating the residual stress from the measured angles and typing a report. This automation has eliminated the tedium of the manual X-ray data accumulation and of the residual stress calculation. The online control has also permitted improvements in the technique not practicable with the manually performed measurement of residual stress.

The use of conventional θ/2θ diffraction methods for the characterization of polycrystalline thin films is not in general a satisfactory technique due to the relatively deep penetration of x-ray photons in most materials. Glancing incidence diffraction (GID) can compensate for the penetration problems inherent in the θ/2θ geometry. Parallel beam geometry has been developed in conjunction with GID to eliminate the focusing aberrations encountered when performing these types of measurements. During the past yearwe developed a parallel beam attachment which we have successfully configured to a number of systems.

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.

Reference intensity ratios (RIRs) with zincite (ZnO) as the internal standard have been measured and calculated for key phases in coal combustion solid residuals. Detailed comparisons of measured and calculated corundum RIRs (converted from zincite RIRs), and literature I/Ic values led to the conclusion that for best results, laboratory measured values must be used. Using measured zincite RIRs and standard mixtures of important crystalline phases, a protocol for routine semi-quantitative analysis has been developed. The need to grind under ethanol to minimize decomposition of hydrated phases was demonstrated. An unusual procedure employing mixed peak and integrated intensities in the RIR of one key phase, ettringite (Ca6Al2(SO4)3(OH)12-26H2O), has been adopted for this protocol.

Large single crystals of ammonium dihydrogen phosphate (ADP) have been grown from solutions of reagent grade materials by means of precisely controlled temperature programs. We have studied the perfection of these crystals by means of double-crystal rocking curves and diffraction topographs. In the course of this study, effects associated with various techniques of sectioning and polishing specimens from these crystals were examined. A combination of string sawing and chemical polishing procedures produced specimens exhibiting the best diffraction characteristics. Results obtained from surfaces so prepared are tentatively taken as being characteristic of the bulk crystal and may be interpreted in terms of longrange strain fields and imaging of both emergent and nonemergent dislocations. In some specimens, regions of 1 cm2 or more have been found to be free of defect images and to have uniform reflectance.

The perfection of some specimen pairs and the intrinsic properties of certain reflections suggest their possible application to spectroscopic problems. Some crystal pairs cut parallel to (101) planes have exhibited physical resolving powers of 104 at 8.3 Å; others cut for the 600 reflection have given 4 x 105 at 1,5 Å, These crystals deteriorate on exposure to moist laboratory air and preservation techniques had to be employed.

In X-ray diffraction techniques intensity of radiation is an important factor. In addition, when high resolution is required, the usual collimating system restricts the width of focus that can be effectively used. Accordingly, a prime requirement is that the target loading shall be high to give the greatest possible brilliance at the focus. An X-ray unit designed to achieve these qualities will be described. Its use with a spectrometer and with a number of cameras for differing crystallographic studies will be illustrated.

The tube operates with alternative electron guns, one of them to provide a circular focus of 40 microns in diameter and the other to provide a line focus of 1.4 millimeters in length and 0. 1 millimeter in width.

X-ray diffraction observation of the material beneath the fracture surface provides failure analysists with useful information to judge the mechanical condition of fracture.

In the present paper, stress corrosion cracking (SCC) tests were conducted by using the bluntly notched compact tension (CT) specimens of 200°C tempered AISI 4340 steel in a 3.5 NaCl solution etwixonmeat. The distribution of the residual stress beneath the fracture surface near the root of the notch was measured with the X-ray diffraction technique. The effect of the notch root radius on crack nucleation with stress corrosion was discussed on the bases of the results of X-ray observation.