[en] A general overview of the investigation of aluminium and some aluminium alloys by using Moessbauer spectroscopy and positron annihilation spectroscopy is presented. The detection of iron and cobalt impurities in aluminium, and the determination of Fe-Al bond by Moessbauer technique is described in detail. The various possibilities of positron annihilation spectroscopy, including 2γ angular correlations, Doppler broadening, positronium detection, electronic structure studies, various lattice defect studies, investigations of Al-Zn, Al-Mg, Al-Mn, Al-Si, Al-Ge, Al-Sn alloys, vacancies, and surface studies are also presented. (R.P.)

[en] The principle of Moessbauer spectroscopy, i.e. the phenomenon of nuclear resonance absorption of gradient and quadrupole moment and that of the magnetic field and magnetic moment of the nucleus, conclusions can be drawn on the crystal structure and the magnetic characteristics of several elements. Evaluating the Moessbauer spectra, the concentration rates of the phases can be determined and useful information is obtained, e.g. in metallography. (V.N.)

[en] An introduction of the principles of the Moessbauer effect, and its utilization in materials science as Moessbauer spectroscopy is given. A special metallurgical application of the Moessbauer spectroscopy in phase analytical studies, the analysis of residual austenite phases in hardened steels is presented. (R.P.) 25 refs.; 18 figs

[en] Using Moessbauer spectroscopy and X-ray diffraction as analytical tools, an 'anomalous' α-γ phase transformation observed previously in steels was studied. It was shown in this work that this phase transformation is a feature of the Fe-12Cr-4Ni ternary alloy, and the ageing-time dependence of the γ-phase formation follows Avrami kinetics representing a diffusion controlled process. The activation energy of the process was also determined. The equilibrium composition of the samples could be interpreted in terms of calculated phase diagrams of the Fe-Cr-Ni system. On the basis of the hyperfine-field distributions derived from the spectra it was shown that two processes take place in the ferromagnetic α-phase during the ageing at different rates in which the slower one is in accordance with a decrease of the chromium concentration in the α-phase owing to the γ-phase formation

[en] The Moessbauer spectra recorded in quenched liquids at low temperature gives information about the following properties of the studied solutions: hydration and solvation of the salts containing Moessbauer active isotopes; complexes formation and hydrolysis in the solutions of compounds possessing iron, tin, europium or antimony; electron-exchange reactions between tin(II) and tin(IV) and iron(II) and iron(III). The equilibrium and stability constants of the species of the solutes can be obtained on the basis of the line intensities of the Moessbauer spectra. The Moessbauer study of the paramagnetic spin relaxation and superpara magnetic behaviour of the iron(III) salt solutions can give information about the polymerization and particle size distribution of the iron(III) compounds, respectively. (author)

[en] New user-friendly software for analysis of Moessbauer-spectra has been developed. Evolution Algorithm is used for global search of Moessbauer parameters in order to enhance the reliability of the obtained results. Fitting of Lorentzians, Pseudo-Voigt line profiles, deriving hyperfine-field distributions including correlations and combinations and Moessbauer Line Sharpening by Fourier transformation provide a wide range of applicability

[en] This chapter of a textbook presents an overview of an important aspect of nuclear physics and nuclear chemistry. The effects of the interaction of nuclear radiation with substances are classified according to the acting particle, and the reacting constituents of the substance. The interactions of alpha radiation with matter (slowing down, scattering), of electron radiation with matter (slowing down, Cherenkov radiation, backscattering, absorption, annihilation), and of gamma radiation with matter (Compton effect, photoelectric effect, pair formation, absorption) are discussed. The reacting constituents are categorized as shell electrons, atomic nuclei, the Coulomb field of nuclei. In the complex interactions, the Auger effect and the photoelectron-induced bremsstrahlung is discussed. (R.P.)

[en] The possibility of determining the changes in the radius, the surface of a particle and the thickness of a foil in chemical reaction on the basis of transmission Moessbauer spectra is suggested. The ratio of the areas of the partial Moessbauer spectra is equivalent to the change in the quantity of a substance containing Moessbauer atom. Calculations to estimate the particle size changes were made for the reaction between iron powder and either aluminophosphate or chromophosphate or alumino-chromophosphate. This method may be useful in studying corrosion processes, solid phase reactions. (V.N.)

[en] In this chapter of the textbook for chemists the isotope enrichment methods are overviewed. The subsections are: General characterization of the methods used for isotope enrichment, Distillation and chemical exchange, Electrochemical methods, Diffusion methods, Isotope enrichment through centrifugation, Single-stage methods, Cascades

[en] Non-destructive analytical methods based on interactions of nuclear radiation with matter are overviewed in this chapter of the textbook. The three major categories discussed are Moessbauer spectroscopy based on the nuclear resonance absorption of gamma radiation, positronium chemistry developed from the study of the interaction of positive beta radiation with matter, and the chemistry of muonium and muonic atoms connected with the interaction of mesons with matter. (R.P.)