The microbeam X-ray diffraction technique was used for the evaluation of fracture analysis on the fatigued low carbon steel specimens.

It is possible to evaluate both monotonic and cyclic plastic zone sizes beneath fatigue fracture surface. Thus the stress intensity factor can be estimated.

An X-ray emission spectrographic method of analysis is presented for the determination, of rare earth elements in fractions obtained from bastnaesite ore. The method includes the determination of yttrium, thorium, lanthanum., and the rare earth elements in various complex mixtures. The analysis technique is based upon comparing the samples to synthetic standards approximating the composition of the samples. Working curves are plotted on an absolute intensity basis, with, no correction for background. Examples of working curves and the analyses of typical rare earth concentrates are included. The selection of spectral lines for the various sample matrices is discussed. A special technique is used for samples in which rapid hydration and carbonation occurred.

By analyzing synthetic samples of known composition, the accuracy of the method was determined. The error of analysis was about 3 per cent of the amount present in the range from 5 to 100 per cent and about 7 per cent in the 0.2 to 5 per cent range. A maximum of about 40 samples per day may be analyzed for 7 elements each. The advantages and disadvantages of the method are discussed.

A Search/Matcti program lias 'beea written for the IBM PC AT computer that is capable of -using "background - subtracted, digitized 2-ray powder diffraction scans as inputs in addition to the d/I data traditionally used. This novel procedure has proved especially effective when numerous unresolved lines are present in the pattern. The method is also less demanding of data quality thaii the peak location programs. The program may he extended to searching & data "base of digitized standard patterns.

The program, has several parameters that can- "be adjusted, including chemistry. The results from the Johnson/Vand list type of output are directly accessible to the interactive graphics program. This gives the diffraction!st a fast method for verifying the phase identification. Because of the speed of fixed point computation techniques, the 52,791 pattern file can be scanned in about 90 seconds.

This paper will illustrate the utility of the program.

Layered Synthetic Microstructures (LSM) for XRF instruments became commercially available in the early 1980's. It was quickly recognized that these devices improved the efficiency of diffraction for the elements boron through magnesium considerably over the LOD soap multilayers and single crystals available at that time. LSM devices of 40, 50, 80, and 120 ang-strom (2D) spacing were offered at first. Gradually, many different 2D spacings and compositions have become available, each with its own special area of application, usually limited to one or two elements.

The characterization of multi-layer thin film properties, such as thicknesses of layers or concentrations of elements, using the fundamental parameter method is discussed. Experimental results are shown for repetitive multi-layers of up to 80 layers. Furthermore the impact of using different characteristic lines on the information depth and the resolving power is discussed for single layers and repetitive multi-layers. Finally, thin films containing light elements are presented; in this case the conventional fundamental parameter theory fails to provide accurate results, perhaps due to the neglect of the impact of the secondary excitation by photoelectrons.

The real-time x-ray powder diffractometer control system AUTO incorporates several advances in data collection and analysis. Counting procedures for selected area data collection are optimized to achieve either a preselected statistical error in minimum time or a minimum error in fixed total time. Run files are employed to greatly simplify quantitative analysis procedures and for controlling repetitive runs. External calibration curves for 20 are used to eliminate all but sample dependent aberrations to peak positions. A generalized data file structure is used to document the instrumental variables and sample parameters.

A review is given of the main gas-discharge sources and auxiliary equipments which were used in soft and ultra-soft X-ray emission spectrometry. Special attention is paid to the basic principles and instrumentation of low-energy electron-induced X-ray spectrometry (LEEIXS) whose excitation source is an electron beam generated in a glow-discharge system. Capabilities of LEEIXS in surface and thin film analysis and characterization are illustrated by examples dealing with control and optimization of surface treatment and thin film deposition processes. Sensitivity of the technique down to the submonolayer range and influence of backscattering phenomena are shown.

An X-ray small-angle scattering instrument is described which is used for recording X-ray diffraction patterns or small-angle X-ray scattering curves in an angular region very close to the direct beam. The measurement of X-ray intensity is accomplished with standard geiger or scintillation counter techniques. The instrument is designed for use with a spot-focus or vertical-line X-ray source, In essence, it is a multiple-reflection double-crystal diffractometer, based on a concept developed by Bonse and Hart, employing two grooved perfect germanium crystals arranged in the parallel position. Multiple diffraction from these crystals produces a monochromated X-ray beam which can be several millimeters wide while still exhibiting extremely high angular resolution. As a result, effective sample volumes can be employed with maximum volume-to-thickness ratios. The principal features of the instrument are discussed with emphasis on the advantages of this device over those employing complex slit systems and film-re cording techniques, Data are presented to illustrate the operation, intensity, and resolution of the unit.

Fluorescent x-ray speorographic studies of mineral systems were begun in the Metallurgy Division of the Denver Research Institute in 1953. These studies were concerned with several techniques but the primary research emphasis was placed on a method involving conjunctive analyses by monochromatic x-ray absorptiometry and fluorescent x-ray spectrography.

Experimental data for mineral systems with wide variations in matrix compositions exhibit departures from simple calibration curves relating intensity and concentration for an element in a series of samples analyzed by simple fluorescent x-ray spectrographic procedures.

Absorptiometric measurements are made with a thin layer of the mineral sample as an absorption filter for the monochromatic x-rays emitted by the element in question. The results of these measurements provide information for improvement of the simple correlation of intensity and concentration by manipulation of the experimental data with various operations based on Beer's law of radiation absorption.

The results of work at the Denver Research Institute indicated the feasibility of the fluorescent x-ray spectrographic-absorptiometric method and the current work is an extension of the study of basic fundamentals, mechanical factors and practical applications of the technique.

Methods for rapid and accurate analysis of coating composition and thickness are of major importance for the semiconductor industry. Typical coating problems are Al, Au or Pt coatings on metal and Cr/Ni alloy or SiO2/P2O5 glass on Si wafers. Due to the nature of the coatings ana tne variety of elements, a software package, COAT95 has been developed to cover the following three possible situations:

• 1. Single element coating for thickness only.

• 2. Compound, elements A and B, coating on substrate element S, for composition and thickness.

• 3. Compound, elements A and S, coating on substrate element S , for composition and thickness.

The main goal of the COAT95 software is to have all possible models for the single layer coating problems of the semiconductor industry.

Various kinds of compounds containing arsenic have been used in the world as rat poisons, agricultural chemicals and so on. In the field of semiconductor materials, AsH3 is used as a doping gas on silieon-wafer substrates and GaAs is now also investigated as a wafer substrate instead of Si wafer.

As for quantitative analysis of arsenic, atomic absorption spectrometry (AAS) and inductively coupled plasma atomic-emission spectrometry (ICP-AES) have often been used. In these methods, usually, oomplioated pretreatments such as preconcentration and separation have been needed in order to obtain reproducible values for arsenic.

An X-ray diffraction technique was used to measure residual stresses in Ti-6Al-4V and Ti-8Al-1Mo-1V sheet created by glass-bead peening, sand and aluminum oxide blasting, and a vibratory tumbling treatment. For peening and blasting, the use of larger particle sizes produced greater compressive stresses. In the case of the vibratory treatment, an increase in vibratory frequency or treatment time increased the compressive stress. Glass-bead peening caused a 10% reduction in yield strength while the other treatments had little effect on the tensile properties. Significant stress relaxation occurred in all the treated Ti-6Al-4V coupons exposed at 600° and 800°F.

Both ammonium chloride and ammonium bromide undergo a transition, with rise in temperature, from an interpenetrating simple cubic (II) to a face-centered cubic (I) lattice at 183 and 137°C, respectively, and both the low- and high-temperature forms give a complete series of solid solutions. We have determined the lattice constants of the high-temperature solids at about 250° as a function of composition, and redetermined the lattice constants of the low-temperature solids at room temperature. The solutions were made by crystallization from water, followed by stirring in contact with mother liquor for at least three weeks at room temperature. Measurements were made with a Norelco- Philips diffractometer and recorder, with Cu Ko. radiation. For the high-temperature work, a simple, inexpensive heating apparatus was developed. The only previous data reported for the high-temperature forms are the lattice constants of the pure components given by Bartlett and Langmuir.

The low-temperature solutions showed negative deviations from Vegard's rule at both ends of the concentration range and a slight positive deviation elsewhere when high-angle data were used. The high-temperature solutions showed marked positive deviations from Vegard's rule over the whole compositions range. Values for the pure components agreed reasonably well with those of Bartlett and Langmuir.

The progress of the change II → I with time was followed for some of the solutions in the neighborhood of the transition temperature in an attempt to reveal the mechanism of the process.

Recent advances in MOS integrated circuit technology have opened new, high-volume applications utilizing epitaxial silicon-on- insulating substrates. To provide good quality heteroepitaxial silicon films for the semiconductor industry, a development program has been established to improve both the crystalline quality and the fabrication techniques for the most promising current substrate, magnesium aluminum spinel.

The role of X-ray diffraction techniques in the investigation of crystal quality, substrate surface quality, and epitaxial film quality are discussed, and results interpreted as the program is traced from crystal growth to epitaxial film analysis.

There is a great deal of interest by the electronics Industry in understanding the reactions occurring at the interface between a solid metal and a liquid solder or braze. This is due to the complex nature of current microelectronics Packaging, where soldering or brazing operations often involve complex metallurgies and tightly controlled furnace profiles. However, to date only a few studies have been carried out on the reaction kinetics at a liquid metal-solid metal interface. This is due in part to the difficulty in carrying out such , experiments. In the past, two main techniques have been used to obtain solid-state kinetic data. The first, quantitative metallography, is slow and tedious to perform, and generally of limited accuracy. The second technique involves measuring the change of some property, such as electrical resistivity, that is a function of the concentration of one of the phases. The main disadvantages of these techniques are that absolute values of concentration are not obtained, and that the relationships between a property and constitution are rarely available. In addition, most physical properties are sensitive to factors other than constitution, and interference from these factors can often result in erroneous data.

Three variables in the identification of crystalline multiphase unknowns by computer search/match methods were examined: presence or absence of chemical information; varying quality of d-I diffraction data; use of a large data base vs a data base having about 10% as many entries--both contain the unknown phases. The results showed that the search/match using average quality d-I data with chemical information was quite successful, while that obtained using higher quality d-I data alone missed one of four phases. It took only half the time to obtain the average d-I data plus chemistry as it did to obtain the higher quality data. Searching the smaller data base with the higher quality data alone resulted in an identification of all phases with high reliability.

To assure an adequate supply of such critical metals as nickel and chromium, extraction procedures must be developed to process low grade domestic sources. In optimizing these procedures it is essential to use suitable analytical procedures to characterize the materials, identify phase transformations, and determine metal and mineral association of the critical metallic elements through all stages of the process. Evaluation of complex sources such as laterites requires special material handling techniques coupled with X-ray diffraction and with optical and SEM analyses of many individual particles. A joint study by the Bureau of Mines and the Denver Research Institute using these procedures has resulted in optimizing a new modification of an extraction process.

X-Ray powder diffraction (XRPD) techniques are compatible with studies of the transplutonium elements and their compounds. Only limited amounts of these materials are available for study, and microchemical techniques exist for the preparation of samples suitable for X-ray analysis. The microscale syntheses, systems for annealing/ quenching to bring about phase transformations, and a modified powder diffraction camera are described. Examples of recent and current work are presented to illustrate some specific applications of XRPD to basic, transplutonium element research.

Several design concepts were evaluated for on-stream X-ray analysis, chief among which were: (1) sample presentation, (2) X-ray spectrograph and (3) data handling. The sample is presented to the X-ray spectrograph through a vertical cell having a mylar window and a device to measure variations in sample density. The X-ray spectrograph is of fixed-channel, modular design, with a capacity of up to six channels, and is designed for use in industrial environments. The complete spectrograph can be translated in a horizontal plane to position itself and determine the elemental composition in a series of sample cells. The data handling uses digital circuitry to permit normal use of analog readouts or digital data logging systems. Operational data are given for on-stream analysis.

The lattice misfits between γ and γ' phases in Ni-base superalloys (single crystal) were accurately determined for filings of specimens by using both a conventional X-ray tube focusing diffractometer(CXRFD) and a synchrotron-radiation parallel beam X-ray diffractometer (SRPXRD). All reflection peaks measured with the CXRFD were in a cluster of overlapping peaks because of the very small differences in the lattice parameters of both phases and the instrumental broadening due to X-ray optics including the spectral distribution of Xray source such as CuKα doublet. The deconvolution method was applied to remove the instrumental broadening from the peaks measured with the CXRFD. The window functions for the deconvolution method were calculated from CuKα doublet reflection of Si standard by a nonlinear least-square method.

The instrumental broadening of SRPXRD was much smaller than that of CXRFD since the monochromatic X-rays produced single peak profiles and constant profile shape over a wide 2θ range. A profile fitting with a pseudo-Voigt function was used to determine 2θ angles to 0.0005 deg. for the synchrotron powder data. The peak angle and shape reflected from γ' phases in γ-matrix and those fron electrochemically extracted γ'-phase were significantly different.