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A general expression for x-ray interference profiles of a binary alloy showing crystals of different concentration and thus different lattice dimensions is deduced. This expression contains previously reported relations as special cases, which are discussed briefly. It is not restricted to systems of total solid solubility or cubic lattice.

Simultaneous grain boundary-, surface- and lattice diffusion in hypothetical thin film couples of miscible components was computer simulated. On this basis the diffusion into fixed and moving grain boundaries is discussed with respect to the determination of diffusivities by depth profiling methods. The data evaluated from the synthesised depth profiles according to Whipple-Le Claire as well as to Gilmer and Farrell were compared with the diffusivities used for the computation. Agreement was found for systems with a fixed grain boundary network. Moving grain boundaries, however, may cause errors of an order of magnitude towards lower grain boundary diffusivities

A method for the retrieval of concentration spectra of crystalline mixtures from x-ray diffraction profiles is described. Both spectra are associated with an integral equation which can be simplified to yield a set of linear equations. Solutions are readily obtained by triangular decomposition since the equations are typically described by band matrices. The method has been tested with simulated diffraction profiles to allow for a variety of options concerning the concentration spectra. The procedure is well suited for binary alloys containing crystals of different structure and lattice parameters. The time consumption of the calculations is significantly reduced as compared to hitherto available methods.

On the basis of hypothetical thin film couples in which a grain-boundary supported diffusion process is simulated, it is shown that the concentration spectrum may contain maxima which would not occur if the process were governed by lattice diffusion only. As such maxima consequently appear in the diffraction pattern, real diffraction profiles of interdiffusion layers must be interpreted carefully, keeping in mind that diffraction peaks need not necessarily be associated with a particular phase. The thin-film diffusion system Au-Cu is chosen as an example to demonstrate experimentally the generation of diffraction maxima which must not be attributed to phase formation.

Abstract: Computer simulation of superimposed lattice, grain boundary and surface diffusion, characteristic for polycrystalline thin film diffusion systems, was performed by way of discretisation of the nonlinear diffusion law. In order to give a vivid impression how such a complex process takes place under some typical conditions we have chosen pseudo three-dimensional computer plots of the spacial distribution of the concentration instead of the commonly used iso-concentration diagrams. The following cases are considered:

A short literature survey on the subject is given with special emphasis on discrepancies and contradictional interpretations of results. Our own experiments on thin copper films evaporated onto glass substrates at different condensation temperatures are reported. Density values were calculated from the film thickness, which was measured by Kiessig's method and from the deposited mass determined by atomic absorption spectrometry as well as gravimetric measurements. The density defect decreases with increasing film thickness, as already established, and also with temperature.

Contrary to brittle material, the equilibrium grainsize for ductile powders is often approached as an oscillatory function of time. The following paper investigates this behaviour by means of a geometrical analysis of the powder particles, using wet-milled aluminium powder as an example. For the description of the milling kinetics we have used Hüttig's milling functions which are obtained from a sieve analysis, the measuring of the specific area of a powder monolayer, and the determination of the space-filling.

The validity of some assumptions included in the theoretical basis of several x-ray methods for the determination of concentration spectra in inhomogeneous solids, is analysed critically by theoretical considerations.

Abstract: Limited diffusion spaces which may be easily traversed by atoms diffusing along grain boundaries generally cause thin-film diffusion to differ from common bulk diffusion. These peculiarities were studied in Ag−Au thin-film couples by means of electrical resistance measurements. Diffusion coefficients were found to decrease with annealing time mainly as a consequence of recrystallisation and recovery in the films during the diffusion anneal. It is shown that the rate of homogenisation is fairly independent of the film thickness thus giving evidence that diffusion into the crystallites occurs out of the grain boundary network rather than directly through the couple interface. Effective diffusion coefficients determined between 150 and 250 C ranged from 10−14 to 10−16 cm2 s−1 revealing an activation energy of 25 kcal mol−1.

The diffusion coefficients in concentration modulated amorphous CuAg thin films were measured. Both the mean and the isoconfigurational diffusion coefficients obey an Arrhenius relation with pre-exponential factors 8.7 × 10−5and 7.3 × 10−3cm2/s and activation energies 0.85 and 1.18 eV, respectively. The amorphous structure of the films (examined by resistivity measurements and electron microscopy) was maintained despite an atomic mobility large enough for long range diffusion.

The analysis of X-ray reflections allows for the determination of the grain dimension in the direction of the bisector of the incident and scattered radiation. It is shown that correct results will be obtained only as long as the grain dimensions perpendicular to this direction are sufficiently large. The possible errors are estimated. The conditions for the determination of the shape anisotropy are discussed.

In order to separate diffusion induced changes in the electrical resistivity of quench-condensed amorphous AgCu alloy films from such arising from other causes several trial experiments have been performed. Such films consisting of alternating Ag60Cu40/Ag40Cu60layers showed a specific resistance rise which revealed the following peculiarities:

Abstract: An x-ray method for the determination of concentration profiles in thin film diffusion couples is presented. This method is based on the theory of Fourier analysis of x-ray diffraction profiles which is generalized to polycrystalline samples showing nonuniform lattice parameter. A Fourier synthesis of the concentration spectrum is possible when the influences of the particle size and the strain in the sample as well as the instrumental function are eliminated from the measured diffraction profile. This can be done by means of reference profiles obtained from layers of the diffusion components. Absorption of the radiation in the sample is negligible when diffusion couples of symmetrical sandwich structure are used. The method is tested experimentally in the system Au-Cu.

Es werden die systematischen und statistischen Fehler bei der Ermittlung der Kristallitvolumina nach STEPHEN und BARNES sowie nach EBEL behandelt. Außerdem wird eine vereinfachte Variante der erstgenannten Methode, welche im Gegensatz zu dieser nur eine Aufnahme erfordert, aufgezeigt. Aus einer Gegenüberstellung der drei Verfahren ergeben sich ihre zweckmäßigen Anwendungsbereiche.

Summary A novel microhardness-tester has been designed for loads between 10-2 N and 5 x 10-5 N. The apparatus can be operated in a scanning electron microscope without installation of additional adjusting shafts. The force is generated electromagnetically, transduced to the indenter (diamond cone or pyramid) by bending a double leaf spring, and measured by means of strain gauges fixed to the springs. The indentation cycle is fully programmable and is controlled by the strain gauge signal. The equipment can be tilted with respect to the electron beam thus making possible the observation of the tip during indentation.

In the submicroscopic range crystallite sizes which are determined by means of various X-Ray methods show often considerable discrepancies .The reason for this are different analytical approximations made in the underlying theories of these methods. The results of the analysis of the X-Ray line width of wet-milled alluminium powder are compared with crystallite sizes which were obtained by dark-field electron mircoscopy. The basic method was Hall's analysis using different elimination procedures for apparative parameters and grain-size and internal strain contributions. The best agreement with the electron microscopic data was obtained by the Wagner-Aqua method combined with an approximation of the strain- and particle size profiles by Gaussian functions.