RBS investigations of ion beam mixed hard coatings on tool steel

Silicon nitride hard coatings on tool steel produced by ion beam mixing following sputter or vapour deposition were investigated by RBS and Vickers microhardness measurements. Atomic mixing in the coating/steel interface region resulting in an improved adhesion and in a significant increase of the microhardness of the surface layers was found. Ion beam mixing with gas ions and high fluences leads to blistering of the implanted atoms in the silicon nitride layer.     

Oxygen rearrangement of molecular ions of 3-phenylpropionates

The oxygen rearrangement in molecular ions of 3-phenylpropionates has been investigated with the aid of mass analyzed ion kinetic energy spectra. Elimination of an allyl radical followed by expulsion of ketene from the molecular ion of allyl 3-phenylpropionate is shown to result in formation of protonated benzaldehyde. The oxygen rearrangement has been found to be inoperative in ionized methyl 3-methyl-3-phenylbutyrate. [M ? CH₃ ? CH₂CO]⁺ ions in the spectrum of the latter compound are formed by elimination of the 3-methyl substituent and subsequent methoxy migration.     

Synthesis and properties of a novel family of fluorous triphenylphosphine derivatives

A novel approach to the preparation of perfluorotail-functionalized triarylphosphines using a p-silyl substituent as the branching point has been developed. This approach enabled the attachment of between three and nine perfluorotails per phosphorus atom, resulting in the production of highly fluorous tris[p-(1H,1H,2H, 2H-perfluoroalkylsilyl)aryl]phosphines, P[C(6)H(4)-p-SiMe(3)(-)(n)()(CH(2)CH(2)C(x)()F(2)(x)()(+1))(n)()](3) (n = 1, 2, 3; x = 6, 8), containing between 50 and 67 wt % fluorine. (31)P NMR studies indicate that the phosphorus atoms, and consequently the sigma-donor and pi-acceptor properties of these phosphines, are not influenced by the electron-withdrawing perfluoroalkyltails. The fluorous triarylphosphines are readily soluble in fluorous solvents and display fluorous phase preference in several fluorous biphasic systems. The phase partitioning of these fluorous ligands, as well as their donor properties, is discussed in relation to their potential for fluorous biphasic catalyst separation.     

Magnetic structure of Fe−Si−Al films implanted with Al and N ions

Changes in the magnetic structure of Fe–Si–Al films due to Al and N ion implantation were studied by⁵⁷Fe Conversion Electron Mössbauer Spectrometry (CEMS). The peaks of the magnetic sextets due to the crystalline films became broader by implantation with 5×10¹⁶ Al/cm², suggesting the formation of amorphous phases. In the CEM spectrum of one sample with large grains implanted with 1×10¹⁷ Al/cm² a crystalline -Fe phase appeared. N implantation with the same dose did not amorphize the sample but the components with high magnetic hyperfine fields were enhanced.