Corrosion-related defects in pure Al and AA 2037 Al alloy have been investigated by positron beam-based Doppler broadening energy spectroscopy. Defect profiles have been analyzed by measuring the S parameter as a function of incident positron energy up to 30 keV. When pure Al samples are immersed in 1M NaOH for various times, a significant increase in the S parameter near the surface is observed. This implies that the corrosion process involves the creation of defects and nanometer voids. In contrast, a significant decrease in the S parameter is observed after the corrosion of water-quenched Al alloy by the same method, which is interpreted as being a result of Cu enrichment near the metal-oxide interface layer.

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hA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, 117813 Moscow, Russian Federation. Fax: + 7 (095) 135 5085.Oxidation of N-aminophthalimide with lead tetraacetate in the presence of spiro(I-pyrazolinecyclopropanes) at temperature from -20 ~ to -30 ~ resulted in thc formal generation of phthalimidonitrene followed by its addition at the N=N bond of the pyrazolme ring to form 5(3)-substituted N-{spiroll-pyrazolinio-3(5),l '-cyclopropanel}-N-phthalimidoamides (azimines), whose regioisomeric compositions were determined to a large extent by the nature of the substituents in the pyrazoline ring. The structures of phthalimidoazimines were established based on the NMR spectra and X-ray diffraction data. Thermal conversions of the resulting adducts, which proceeded either with retention or with opening of the spiro-fused cyclopropane ring, were studied.

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