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Analytical and Bioanalytical Chemistry (v.361, #6-7)

Ninth International Conference on Solid State Analysis by G. Marx (pp. 513-514).

Nanostructure investigations with the analytical transmission electron microscope by H.-D. Bauer; Reinhold Rennekamp; Jürgen Thomas (pp. 515-521).

Concerning the conventional TEM-imaging as well as the analytical procedures the capabilities are pointed out: electron diffraction, energy dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS). The possibilities of investigation of both nanocrystalline materials and multilayers are discussed, accompanied by examples of current investigations: At alloys, produced by intense milling, at single nanocrystals the imaging by diffraction contrast was successful, the analysis has failed because of the sample thickness. By means of energy spectroscopic imaging multilayers from Fe-SiB/NbCu and Fe/Cr as well as Al₂O₃/TiN have been characterized.

Local crystal textures: experimental techniques and future trends by R. A. Schwarzer (pp. 522-526).

Transmission electron microscopy enables crystal textures to be determined in small specimen areas by measuring SAD or RHEED pole figures. SAD (transmission) pole figures are acquired either by deflecting the diffraction patterns or the primary beam along a cone of 2 · Θ semi-apex angle, or by grabbing the whole diffraction patterns with a CCD camera. RHEED pole figures are obtained from the bulk surface by rotating, at grazing beam incidence, the specimen about its surface normal and grabbing a sequence of RHEED patterns. Since the specimen has to be tilted through large angles, spatial resolution is limited to 1.5 μm in SAD and to 0.1 mm in RHEED pole figure measurement. The major benefits over x-ray diffraction are a high speed and sensitivity. Spatial resolution of individual grain orientation measurement is in the range of 0.1 μm in the SEM with backscatter Kikuchi patterns (BKP) from the bulk, respectively 10 nm in the TEM with transmission Kikuchi patterns (TKP). Using a computer controlled SEM and digital beam scan, more than 10,000 grain orientations per hour are acquired unattendedly. Crystal orientation maps (COM) are constructed by a pseudo-color representation of the individual orientations in the area under study. An x-ray scanning apparatus with energy dispersive spectrometer enables the acquisition of texture as well as element distribution (X-ray microfluorescence analysis) maps at a spatial resolution of some 10 μm.

Chemical-bond analysis of nanostructured materials using near-edge fine structures (ELNES) by R. Schneider (pp. 527-531).

The paper is concerned with the application of combined electron energy loss spectroscopy (EELS) and transmission electron microscopy (TEM) to the characterization of the chemical-bond state of elements at nanometer resolution. Respective information is contained in the energy loss near-edge fine structure (ELNES) usually appearing in the energy range up to about 30 eV above the edge onset. The practical way of chemical-bond analysis was chosen, viz. to compare the ELNES of the feature under investigation with those of known stoichiometry. The efficiency of this special technique is demonstrated for different material systems, particularly fiber-reinforced composites and functional ceramics, having structural details of some ten nanometres, or smaller.

Contributions to accuracy improvement of simultaneous ICP atomic emission spectrometry using multi-line measurements of analyte and internal standard elements Applications for the analysis of permalloy by R. Kucharkowski; D. Jankova; E. Herrmann; A. John (pp. 532-539).

For successful application of simultaneous ICP atomic emission spectrometry for major component determinations in multi-component materials the accuracy of the method has to be improved. As a contribution to solve this problem a combined procedure for multi-component standard sample preparation, optimum calibration and different variations of internal standard corrections is described. Variance-weighted multi-line calibrations give most accurate results. Internal standard corrections are effective, if the time-dependent spectral line intensity fluctuations of the standard and the analyte elements are well correlated. Their sensitivities against some responsible device parameter variations are investigated. On the basis of multi-line measurements of the analyte and internal standard elements a “group-selected internal standard correction” (GS-ISC) method is applied and results in relative errors of less than 1% even for extreme fluctuations of the raw intensities. For rapid routine determination methods of materials with variable element compositions the added line intensities of the internal standard element can be used to correct the added analyte line raw intensities (“intensity addition internal standard correction” (IA-ISC) method). These accuracy optimization procedures are applied for the analysis of the soft magnetic material permalloy using the internal standard element In.

The effect of water vapor on the oxidation behavior of 9%Cr steels in simulated combustion gases by H. Nickel; Y. Wouters; M. Thiele; W. J. Quadakkers (pp. 540-544).

The effect of the O₂ and H₂O content on the oxidation behavior of the 9%Cr steel P91 was studied in the temperature range of 600–800 °C. The oxidation rates under the various experimental conditions were determined by in-situ thermogravimetry. In dry oxygen a protective scale growth occurs with an oxidation rate controlled by diffusion in the scale. In presence of water vapor, after an incubation period, the scales become non-protective, as a result of a change of the oxidation limiting process. The water vapor effect is especially apparent in the temperature range of 600–700 °C, whereas at higher temperatures hardly any effect was found. The destruction of the protective scale by water vapor does not only depend on the H₂O content but also on the H₂O/O₂-ratio.

Identification of amber and imitations by near infrared reflection spectroscopy by A. Golloch; Stefan Heidbreder; Christoph Lühr (pp. 545-546).

Imitations of amber have been prepared since a long time, but the number of imitations is increasing since modern polymers are available. At present, many imitations are based on a few synthetic polymers and even experts have some problems in distinguishing between real and falsed amber without destruction of the material. IR-Spectroscopy or pyrolysis combined with gas chromatography/mass spectrometry are very efficient methods in identifying amber and imitations but these methods need a sample preparation. By means of near infrared reflection spectroscopy it is possible to identify amber and imitations without any sample preparation in a short time. Optimization of the method and the application are discussed.

Interface analysis of new tooth filling materials by C. Ziegler; B. Reusch; J. Geis-Gerstorfer (pp. 547-553).

Surface analytical methods such as scanning electron microscopy (SEM), scanning force microscopy (SFM), energy dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS) were used to study the surface properties of amalgam substitutes as tooth filling materials. In particular the corrosion resistance of new gallium restorative materials was determined. To give relevant practical data, the measurements were performed before and after storing the alloys in artificial saliva to simulate physiological oral conditions. Subsequently an analysis of the artificial saliva was carried out with atomic emission spectroscopy with inductively coupled plasma (ICP-AES). Selective corrosion of different phases and a high gallium release could be determined.

Porous silicon: repeatability of generation? by G. Sperveslage; J. Grobe; G. Egbers; A. Benninghoven (pp. 554-557).

A systematic investigation of the preparation of porous silicon layers (PSLs) on silicon wafers by anodic treatment in hydrofluoric acid/water/ethanol mixtures under various conditions was carried out with the aim to develop a repeatable process for homogeneous layers. The preparations were controlled by FTIR spectroscopy supported by TOF-SIMS measurements of the uppermost surface area. The repeatability of PLS generation was proved on the grounds of the IR-absorption of SiH_x and O_xSiH_y surface groups with respect to their frequencies and intensities. Uniform properties of PSLs are an essential assumption for defined chemical modifications.

Infrared spectroscopic characterization of the buried interface and surfaces of bonded silicon wafers by M. Friedrich; K. Hiller; M. Wiemer; T. Geßner; D. R. T. Zahn (pp. 558-559).

Basic investigations have been carried out on the characterization of different processing steps in bond preparation using etched <111> faces of silicon wafers for the incidence of the infrared beam to a multiple internal reflection geometry. The method is very sensitive to the surface coverage and interface. Surface activation by RCA cleaning yields an increase of water coverage and a decrease of SiH and CH groups. The detection limit for an oxide layer between silicon wafers has been found to be about 3 nm.

Cathodoluminescence depth analysis in SiO2-Si-systems by M. Goldberg; T. Barfels; H.-J. Fitting (pp. 560-561).

SEM cathodoluminescence (CL) is extended to luminescence center spatial depth profiling by means of electron beam energy E₀ variation and consequently variation of CL excitation range. In this way the CL profile of SiO₂-layers on Si substrate offers a dead layer of luminescence beneath the surface (10–75) nm as well as the SiO₂ oxide thickness with an accuracy of better 10% across a small spot area of less than 1 μm.

Nanoscopic phase-analysis of SiC containing BaTiO3-ceramic by J. Neumann-Zdralek; F. Koschel; A. Röder; H.-P. Abicht; N. Engler; A. Riemann (pp. 562-564).

The formation of fresnoite (Ba₂TiSi₂O₈) from BaTi_1.01O_3.02 by addition of SiC was investigated in the temperature range from 700 to 1350 °C. Solid state reactions at the interface of grains indicate a formation of fresnoite below the temperature of liquid-phase-formation at about 1250 °C.

Auger investigations of thin SiC films by G. Ecke; H. Rößler; V. Cimalla; J. Pezoldt; T. Stauden (pp. 564-568).

Problems of the evaluation of Auger depth profiles of thin SiC layers are caused by a number of effects. These are coverage with an adsorbate layer, preferential sputtering, the change of the peak shapes by chemical bonding states and the broadening of the interfaces by atomic mixing, Auger electron escape depth and original surface, interface and sputtering induced roughness. These effects are investigated and their contribution to the degradation of the depth profile is considered. Atomic mixing simulations including electron escape depth correction are able to reproduce the Auger depth profiles. In special cases the simulation must be convoluted with a resolution function caused by roughness. Thus quantitative conclusions about the layer structure, film composition, impurity distribution etc. are possible.

Microstructure and composition of silicon carbide films deposited on carbon fibers by chemical vapor deposition by D. Dietrich; H. Podlesak; G. Marx; B. Wielage (pp. 568-569).

The microstructure and the composition of CVD silicon carbide films used as fiber coatings in composite materials were investigated by photoelectron spectroscopy and transmission electron microscopy. The films with a uniform thickness of 50 nm consisted of small SiC grains with a mean diameter of 15 nm and showed a stripe contrast in bright field images. Large grains with diameters in the dimension of the film thickness were used for imaging the lattice structure by high-resolution electron microscopy. The results are discussed as a polytype of cubic lamellae of a few nanometers and intermediate random stacking sequences of hexagonal structure.

Investigation of metallization schemes for high temperature devices based on silicon carbide by T. Scholz; R. Getto; K. Gottfried; G. Kurz; J. Kriz; V. Lauer (pp. 570-573).

The suitability of several metallization schemes for high temperature sensors and devices based on silicon carbide was investigated. Auger electron spectroscopy (AES) depth profiling was used for the detection of possible interface reactions and thermal induced diffusion processes. Changes in the structure of the films under the influence of high temperature were observed by transmission electron microscopy (TEM). The maximum operation temperature for the metallization with aluminum as coverlayer was found at 450 °C. The ability of gold with underlying tungsten nitride as diffusion barrier to work at temperatures above 450 °C was shown.

Correlation between mechanical and electrical properties on conductive SiC-fibre reinforced composites by B. Fankhänel; Eberhard Müller; Torsten Fankhänel; Winfried Siegel (pp. 574-576).

Electrical and mechanical properties of ceramic composites are investigated to develop “smart materials” and establish a fracture prediction technique. The “smart materials” are based on silicon carbide fibre-reinforced composites. The SiC-fibres were checked to determine the changes in mechanical and electrical properties during the composites’ production. Samples were produced for the determination of the mechanical strength with in situ detection of the degree of damage by recording the electrical resistance.

Nucleation and crystallisation of amorphous SiC from polymeric precursors by H.-P. Martin; D. Kurtenbach; E. Müller (pp. 576-577).

Silicon carbide is produced from chlorine containing polysilanes. An introduction of oxygen is avoided by strict handling under argon. The thermal behavior of such a material is investigated in this paper. The crystallisation process is characterised by x-ray diffraction and small angle x-ray scattering. NMR and density investigations complete the x-ray results. A stable nanocrystalline structure of the material is found up to 1400 °C. Higher temperatures create a cleavage of nitrogen and carbon monoxide and crystallite growth starts.

In situ investigations of the thermal fatigue behaviour of hot pressed Si3N4 by laser shock loading inside an SEM by Juliane Kadner; Siegfried Menzel; K. Wetzig (pp. 578-581).

The influence of both material microstructure and chemical composition of the grain boundary phase on subcritical crack growth under cyclic heat loading of hot pressed Si₃N₄ ceramics was investigated. The samples were locally irradiated by Nd : YAG high power laser pulses in front of a saw notch, in order to generate high temperature gradients. By combination of the laser with an SEM, material damage such as crack initiation and growth at the surface could be characterised with high lateral resolution and depth of focus. The relevance of high temperature processes like viscous flow of the grain boundary phase to material damage can be deduced from the analysis of subcritical crack growth. On the basis of experimental results a damage model is developed for the high temperature range.

The analysis of Si3N4, SiC and BN by combustion with elemental fluorine coupled to mass spectrometry by K. Ruße; J. A. C. Broekaert (pp. 582-584).

Combustion with elemental fluorine has been used for the decomposition of ceramic powders of Si₃N₄, SiC and BN. Volatile reaction products like N₂, BF₃, SiF₄ and various fluorides of carbon are detected on-line with a quadrupole mass spectrometer. It is shown that thermal separation of the combustion products by controlled release from a cooling trap is useful to decrease limitations by isobaric interferences in quadrupole mass spectrometry. The developed fluorine combustion coupled to a mass spectrometry procedure has been used for the determination of the stoichiometry of Si₃N₄ in which Si could be directly determined.

IR spectroscopic investigations on the determination of the water content in glasses by U. Harder; Heinz Geißler (pp. 585-586).

The IR spectra of glasses of the composition 16 Cs₂O · 10 CaO · 74 SiO₂ with different water contents were measured and quantitatively analyzed with regard to the water content. Nuclear reaction analysis (NRA) was used for calibration. The practical extinction coefficients were determined for the OH vibrational bands at 3500 and 2800 cm^–1. The two-band method of Scholze was applied to IR spectra of three different alkali lime silica glasses containing Na⁺, K⁺, or Cs⁺ as network modifier cations. After correcting the extinction coefficients, this method is very suitable for determination of total water concentrations in glasses.

An X-ray photoelectron spectroscopic study of novel SiON glasses by R. Franke; C. Girgenrath; S. Kohn; M. Jansen (pp. 587-590).

Novel SiON glasses obtained by melting mixtures of crystalline α-SiO₂ and α-Si₃N₄ were investigated by means of X-ray photoelectron spectroscopy (XPS). The incorporation of nitrogen into the SiO₂ network was recently proved by ²⁹Si-MAS-NMR (magic-angle spinning nuclear magnetic resonance) and Si K-XANES (X-ray absorption near edge structure). The Si 2p XPS and the Si KLL XAES (X-ray excited Auger electron spectroscopy) studies of the SiON glasses confirm the formation of mixed structural units (SiO_xN_4-x) by the presence of an additional spectral component energetically located between SiO₂- and Si₃N₄-like signals. The N 1s and O 1s XPS spectra support the conclusion about the incorporation of nitrogen into the SiO₂ network.

On matrix effects in HF-plasma-SNMS analysis of sintered ceramic Ti-Al-(Si)-O by H. Börner; H. Jenett; V.-D. Hodoroaba (pp. 590-591).

For a series of electrically non-conductive, sin- tered ceramic samples with the nominal composition Si_0.05(Al_xTi_1–x)_0.95O_y (x being varied from 0 to 1 in steps of Δx = 0.1), the influences of elemental concentration and of the sputtering frequency in the plasma-SNMS high frequency mode on relative sensitivity factors were investigated. For Al and Ti they show strong matrix effects which may arise from the emission of positive secondary ions.

Characterization of precursor-ceramic conversion in Si-C-(O,N)-systems by thermoanalytical methods by T. Breuning; G. Boden (pp. 592-593).

On-line coupling of thermogravimetry (TG) with evolved gas analysis (EGA)/mass spectrometry (MS) was applied to characterize the organic-inorganic conversion of two synthesized polysilazanes to Si-C-N materials and of one commercial polysiloxane to Si-C-O materials.

Investigations of nanocrystalline ceramics and powders by TEM, AFM and plasticity measurements by E. Müller; C. Oestreich; U. Popp; G. Michel; A. Rendtel (pp. 594-597).

Nanocrystalline zirconia powders prepared by laser evaporation were analyzed by electron microscopy and X-ray diffraction. A very high volume fraction of tetragonal particles was found, although the majority of particles is significantly larger than the equilibrium size of the tetragonal → monoclinic transformation. Nanopowder of yttria stabilized (2.4 mol% Y₂O₃) zirconia was used to prepare nanocrystalline ceramics by pressureless sintering at T = 1400 °C. At T ≥ 1200 °C the samples show superplastic behavior with an activation energy of 585 kJ mol^–1 and a stress exponent of about 1.8.

Phases and solid structures by calcination of precursors for lead-magnesium-niobates by H. Heegn; Michael Trinkler (pp. 598-600).

The preparation of powders for the manufacturing of high tech ceramics determines the quality of materials. Using the precursor for lead-magnesium-niobates (PMN), which was prepared from tartrate stabilized solutions of lead-acetate, magnesium-acetate and niobium-ammonium-oxalate in acetic acid by freeze-drying, both the mechanism of formation and the properties of products could be elucidated by X-ray diffraction, thermal analysis, determination of dispersity by laser diffraction particle sizing, mercury porosimetry and gas sorption measurement.

ESCA investigations on pyrolytic carbon films for fiber coatings by D. Dietrich; D. A. Dietrich (pp. 601-602).

Photoelectron spectroscopy on pyrolytic carbon films revealed a main part of carbon atoms in graphitic planes and a smaller part of functional groups with oxygen bonded to carbon atoms. Oxygen totalled a share of 10 at% and more of the carbon coating. The films with a turbostratic structure consist of nearly parallel oriented atomic layers of hexagonal rings with dimensions in the nanometer scale, which is well known from HREM investigations. The oxygen atoms are proposed to saturate the numerous dangling bonds around these individual atomic planes. The oxygen atoms form double bonds or bridges between carbon atoms.

Study of CVD diamond C(100) by X-ray absorption spectroscopies by M. Lübbe; P. R. Bressler; W. Braun; G. Schaarschmidt; H. J. Hinneberg; D. R. T. Zahn (pp. 602-604).

Surface sensitive x-ray absorption fine structure measurements were carried out near the carbon K-edge on chemical vapor deposited (CVD) diamond and natural diamond. Utilizing different methods, namely near edge and extended x-ray absorption fine structure measurements (NEXAFS and EXAFS), features were found in the spectra which were attributed to non-diamond coordination fractions, such as bulk C-H bonds, graphite-like and more diamond-like coordinated amorphous carbon domains. Both techniques show that the non-diamond fractions consist mainly of diamond-like amorphous carbon.

Investigation of the electron beam induced transformation of Cu3 N-films by N. Lesch; P. Karduck; R. Cremer; A. v. Richthofen (pp. 604-607).

Homogeneous films of metastable Cu₃N were deposited on Si-<100> wafers at 90° C by means of reactive magnetron sputtering ion plating. Under electron bombardment with a focused beam at high current (> 700 nA, 15 keV) these films transform into metallic Cu and N₂. The depletion of N was measured quantitatively by EPMA. Structures with a lateral size of 2 μm consisting of metallic copper were written into the Cu₃N films. AFM surface scans revealed a vertical growth of the columnar grains of the Cu₃N film due to the electron bombardment.

Phase formation process of sputtered NiCr(37:63) thin films by W. Pitschke; W. Brückner (pp. 608-609).

The phase formation process of NiCr(37:63) thin films has been investigated using the x-ray diffraction method. The films were deposited onto Si-wafers by means of d.c. magnetron sputtering. The structure of the as-deposited layers was amorphous. As a result of subsequent thermal annealing the crystallization process took place characterized by the formation of b.c.c. Cr-rich solid solution, metastable σ-NiCr-phase, and f.c.c. Ni-rich solid solution, respectively. Besides lattice constants, grain sizes and texture of the formed phases were determined.

Investigation of the microstructure of IrSiX thin films by R. Kurt; W. Pitschke; J. Thomas; H. Wendrock; W. Brückner; K. Wetzig (pp. 609-613).

The microstructure of sputtered IrSi_X thin films was studied as a function of initial chemical composition and of annealing treatment. The films were investigated ex-situ by optical microscopy (OM) and transmission electron microscopy (TEM). Using OM characteristical differences of brightness in the polarization contrast were used to quantify the phase fractions. Additionally, the grain size distribution was determined. TEM investigations gave evidence for the formation of SiO_X and IrSi at high temperature T > 1200 K as a result of the high affinity of silicon for oxygen.

Investigation of ZnS thin films on Si(100) by phase detection imaging and Young’s modulus microscopy by R. Resch; G. Friedbacher; M. Grasserbauer; S. Lindroos; T. Kanniainen; M. P. Valkonen; M. Leskelä (pp. 613-617).

In this study phase detection imaging (PDI) and Young’s modulus microscopy (YMM) have been used for investigation of ZnS thin films deposited on Si(100) substrates with successive ionic layer adsorption and reaction (SILAR). The additional information obtained by these techniques allows a better interpretation of the topographic images in the case of the determination of the number of grains, their distribution and surface coverage. Moreover, the comparison between PDI and YMM is discussed in order to shed more light on the contrast mechanism in phase detection imaging.

Structural studies of ITO films using grazing incidence x-ray diffractometry by M. Quaas; H. Wulff (pp. 617-618).

Tin doped indium oxide (ITO) films deposited by e-beam evaporation were investigated using grazing incidence x-ray diffractometry (GIXRD). With increasing doping concentration the x-ray peak positions are shifted to lower angles and the line profiles become broader. Rietveld refinements show that tin in small concentrations occupies regular In sites. Line profile analysis reveals that higher tin concentrations cause an increasing of lattice defects, as grain boundaries and microstrains. The results of the structural investigations correlate with resistivity measurements.

Structural characterization of thin films formed or changed on materials by micro Raman spectroscopy by K. Witke; Klaus-Werner Brzezinka; Peter Reich (pp. 619-620).

Micro Raman spectroscopy is shown as a useful method of high spatial resolution in characterization of thin films on or in materials formed or changed as a result of external influences. Identification of black films in the glaze of porcelain, of impairing deposits on components of an ICP mass spectrometer and of tribologically stressed contacts of ADLC films or (Ti,Mo)(C,N) ceramics, respectively, are examples for application.

Characterization of Fe/Cr multilayers by analytical transmission electron microscopy by R. Rennekamp; Jürgen Thomas; Birgit Arnold; Kazutomo Suenaga (pp. 621-625).

Different techniques of analytical TEM were used to investigate Fe/Cr multilayers. These multilayers show a dependence of their electrical resistance as a function of the magnetic field. This effect called giant magnetoresistance can be utilized for example in magnetic recording heads. Typical dimensions of the single layer thickness are in the nanometer region. Therefore the microstructure of this material has been investigated by transmission electron microscopy (TEM). To get additional analytical information energy dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS) can be used.

Depth profiling of Co/Ti – silicide films using total reflection X-ray fluorescence (TXRF) spectrometry combined with low energy ion beam etching (IBE) for sample preparation by W. Frank; A. Schindler; H.-J. Thomas (pp. 625-627).

Solid state phase epitaxy (SSPE) by rapid thermal processing (RTP) of Co/Ti double layers deposited on (100)-Si substrates is a common technique for the production of buried CoSi₂-silicide conducting layers for microelectronics technology. The understanding of the processes during the SSPE silicide formation on the atomic scale needs the study of the elemental depth distributions with nanometer scale depth resolution of all multi-layer elemental constituents at different RTP conditions. A new experimental technique, the laterally resolved TXRF analysis line scan method across the bevelled section of the sample prepared by ex-situ ion beam sputter etching, was used to obtain the multi-element depth profiles. First results on the as evaporated Co/Ti (30 nm thick) double layer system prior to the RTP and on the final CoSi₂/Ti_xCo_ySi_z-system (160 nm thickness) after the RTP were obtained.

Investigation of the metal adsorbate interface of the system silver coumarin and silver hydrocoumarin by means of surface enhanced Raman spectroscopy by E. Vogel; W. Kiefer (pp. 628-630).

Coumarin and hydrocoumarin adsorbed on silver island film were investigated by means of surface enhanced Raman spectroscopy. Polarized Raman spectra of the compounds were recorded and vibrational assignments for some characteristic Raman bands are given. The comparison of these spectra allows conclusions about the orientation of the molecule on the surface.

Surface- and microanalytical characterization of ion-implanted Si-C-N layers by H. Klewe-Nebenius; M. Bruns; H. Lutz; H. Baumann; F. Link; K. Bethge (pp. 630-633).

The development of production methods for carbonitridic hard coatings needs information on depth distributions of the layer components as well as on stoichiometries and binding states of the layer constituents. Si-C-N samples were produced by implanting ¹³C- and ¹⁵N-ions into c-Si <111>, and the implanted layers were investigated by means of NRA depth profiling. Afterwards several samples were characterized by surface analytical techniques, and XPS- and AES depth profiles were measured for typical samples. The measurements confirm the NRA depth profiles and stoichiometries. Furthermore, in all depth ranges C 1s- and N 1s binding energies are observed which are consistent with those of carbonitrides.

Characterization of multilayers by means of EDXS in the analytical TEM by J. Thomas; Reinhold Rennekamp; Ludwig van Loyen (pp. 633-636).

Referring to the characterization of nanoscale multilayers in cross section, the resolution limits of the EDXS method have been investigated. For that purpose EDXS line scan profiles of nanoscale Fe-Cr multilayers have been calculated assuming an increased specimen thickness and different tilts between electron beam and layer interface. The resolution limit seems to be greater than 2 nm layer thickness for regular multilayers. Experimentally a limit of 5 nm was reached.

EDX depth profiling by means of effective layers by Kyaw Myint; T. Barfels; J.-C. Kuhr; H.-J. Fitting (pp. 637-639).

A new approach is described for depth profiling in stratified multilayer samples by recording energy dependent characteristic x-ray EDX(E 0) curves in a scanning electron microscope. An effective layer technique replaces the x-ray excitation function of the heterogeneous target by an equivalent function of a homogeneous sample. First results of thickness determination are shown and compared to direct measurements of film thickness monitoring (FTM) and atomic force microscopy (AFM).

Improvement of the oxidation behavior of Ti1-xAlxN hard coatings by optimization of the Ti/Al ratio by M. Witthaut; Rainer Cremer; Alexander von Richthofen; Dieter Neuschütz (pp. 639-641).

The oxidation behavior of cubic Ti_1-xAl_xN films was improved by decreasing the Ti/Al ratio from 50/50 in the direction of the phase transition between cubic and hexagonal structure. Metastable, polycrystalline, single-phase Ti_1-xAl_xN films were deposited on high speed steel (HSS) substrates by reactive magnetron sputtering ion plating (MSIP). The composition of the bulk was determined by electron probe microanalysis (EPMA), the crystallographic structure by thin film X-ray diffraction (XRD). A Ti_1-xAl_xN film with a Ti/Al atomic ratio of 38/62 was deposited in cubic NaCl structure, whereas a further decrease of the Ti/Al ratio down to 27/73 led to a two-phase film with both cubic and hexagonal constituents. The Ti_0.38Al_0.62N film was oxidized in synthetic air for 1 h at 800 °C. The oxidic overlayer was analyzed by X-ray photoelectron spectroscopy (XPS) sputter depth profiling, EPMA crater edge linescan analysis, and secondary neutrals mass spectroscopy (SNMS). Scanning electron microscopy (SEM) micrographs of the cross sectional fracture were taken for morphological examination. With higher Ti content, the Ti_1-xAl_xN formed a TiO_2-x rich sublayer beneath an Al₂O₃ rich toplayer, whereas the oxide layer on the Ti_0.38Al_0.62N film consisted of pure Al₂O₃. The thickness of the oxide layer was determined to 60–80 nm, about a quarter of the oxide layer thickness detected on Ti_0.5Al_0.5N films. The absence of a TiO_2-x sublayer was also confirmed by XRD. The results show a distinct improvement of the oxidation resistance of cubic Ti_1-xAl_xN films by increasing the Al content from x = 0.5 to 0.62, whereas a further increase leads to the hexagonal structure, which is less suitable for tribological applications due to its tendency to form cracks during oxidation.

Determination of the cubic to hexagonal structure transition in the metastable system TiN-AlN by R. Cremer; Mirjam Witthaut; Alexander von Richthofen; Dieter Neuschütz (pp. 642-645).

Structural transitions of metastable Ti_1–xAl_xN coatings on technically relevant substrates were determined as a function of the Ti/Al ratio. Ti_1–xAl_xN films with different Ti/Al ratios were deposited on high speed steel (HSS) substrates at substrate temperatures of 300 ° and 500 °C by means of reactive magnetron sputtering ion plating (MSIP). A Ti/Al compound target was used as well as a cluster arrangement of one Ti and one Al target for comparison. The composition of the films was determined by electron probe microanalysis (EPMA), the crystallographic structure by thin film X-ray diffraction (XRD). The analyses revealed that films deposited with Ti/Al ratios of 44/56 and 36/64 had grown in cubic NaCl structure, a film with a Ti/Al ratio of 32/68 was two-phase, and a Ti/Al ratio of 25/75 led to a hexagonal film in wurtzite structure. Only small differences of the lattice parameters could be observed in dependence of temperature: At 300 °C the lattice parameters of the cubic structure corresponded exactly to Vegard‘s law, whereas they slightly decreased in the films deposited at 500 °C. The application of a cluster arrangement instead of a compound target resulted in nearly the same lattice parameters and peak shapes.

In-situ and ex-situ examination of the early stages of chemical vapor deposition by H.-R. Stock; C. Jarms; H. Berndt; B. Wielage; A. Hofmann (pp. 645-646).

A cold working steel was coated both with high temperature CVD (TiN) and moderate temperature CVD (Ti[C,N]). AES depth profiles show a significant difference at the interface, where a thin oxide layer remains detectable at deposition temperatures of 750 °C. It could be shown that an impedance signal at a frequency of 13 MHz is well suited to detect the early stages of the growth of a CVD coating.

Mass spectrometric investigations on the vanadium-hydrogen-oxygen system by H. Paulus; K.-H. Müller; G. Kiss (pp. 647-648).

Vanadium of different pre-treatments was exposed to hydrogen in doses D_H2 of up to 1.75 × 10²⁰ cm^–2. The absorption of H by V was investigated by thermal desorption mass spectrometry (TDMS). It was found that H absorption is only possible if oxygen is absent at the surface during the H₂-exposition procedure. The H content of the sample increased with the dose until a saturation was reached. The shape of the H₂-TD-profiles was influenced by Ar bombardment prior to the exposition procedure as well as the presence of oxygen at the surface afterwards.

Point defects in (Ti, Fe)N hard coatings, a Mössbauer study by A. Kirsten; C. Pietzsch; H. Oettel (pp. 649-651).

Reactive magnetron sputtered layers of nitridic hard coatings (e.g. TiN) often show high intrinsic stresses caused by the differences of the thermal expansion coefficients of the layer and the substrate and the incorporation of atoms of sputtering and/or reactive gas atoms in lattice voids. The decrease of hardness and stresses of such layers after heat treatment seems to originate from the out-diffusion of interstitial excess reactive gas atoms (e.g. nitrogen). In this study ⁵⁷Fe Mössbauer spectroscopy on (Ti, Fe)N model layers is used to obtain direct information about the mechanism of the development and variation of intrinsic stresses in nitridic hard coatings in connection with point defects (e.g. excess N). The results of this investigations are supported by X-ray analysis and Glow Discharge Optical Spectroscopy (GDOS).

Investigations of residual stresses in carbon fibre/aluminium-composites using X-ray diffraction by B. Wielage; Gudrun Fritsche; Annett Dorner (pp. 652-653).

Investigations of residual stresses have been carried out on unidirectionally carbon fibre reinforced aluminium using X-ray diffraction. It was found that the carbon exists in compression parallel to the fibre axis and in tension perpendicular to the fibre axis after the fabrication of the MMCs by a liquid infiltration process. Furthermore, it was observed that the intermetallic phase Al₃Ni was in tension (+ 100 MPa) parallel to the fibre axis and in considerable residual compression (– 400 MPa) perpendicular to the fibre axis.

XPS investigations on boron nitride fibre coatings prepared by chemical vapour deposition in comparison to their hydrolytic rate by D. Dietrich; S. Stöckel; G. Marx (pp. 653-655).

Investigations on CVD boron nitride films on fibres by means of photoelectron and X-ray spectroscopy resulted in B/N ratios above the stoichiometric value 1 and oxygen contents up to 25 at%. Compared to the hydrolytic rate of the films an apparent dependence was found on the deposition rate and some evidence of the oxygen concentration. CVD fibre coatings exhibit a hexagonal turbostratic structure with extremely small atomic layer plane dimensions, which was proved by transmission electron microscopy. Corresponding to oxygen concentrations in pyrolytic carbon films with similar structure a model is proposed, where the small atomic layers with dimensions of some nanometers cause a relatively high oxygen concentration in the boron nitride films. The oxygen atoms saturate the dangling bonds. Moreover the B/N ratio extents the expected stoichiometric ratio due to the oxygen atoms at nitrogen sites.

TEM-characterization of rapidly solidified Nb-Al ribbons by B. Arnold; Wolfgang Löser; Monika Leonhardt (pp. 656-659).

In rapidly solidified eutectic Nb-Al alloys a change in morphology from a lamellar microstructure to a globular anomalous eutectic one has been observed. This behavior results from the decomposition of an intermediate metastable tetragonal σ*-Nb₂Al phase. By means of TEM, electron diffraction and EDXS this metastable phase was characterized and the solidification behavior via different transition steps of the metastable σ*-Nb₂Al was elucidated.

SNMS and GDOES studies of the oxidation behavior of TiAl modified by niobium addition by J. D. Sunderkötter; D. D. Gilliland; H. Jenett; V. A. C. Haanappel; M. F. Stroosnijder (pp. 659-662).

TiAl-based intermetallic alloys are promising candidates as structural materials for high temperature applications. However, industrial application is hindered by insufficient oxidation resistance at temperatures above 700 °C in air. The oxidation resistance can be improved by the addition of ternary and quaternary alloying elements, such as niobium. In several studies it has been demonstrated that this element can reduce the oxidation rate dramatically although the underlying mechanism is not yet fully understood. In the present study the influence of niobium on the high temperature oxidation behavior at 800 °C of Ti-48Al-2Cr was investigated. Niobium was added by alloying as well as by ion implantation. Some specimens were pre-oxidized prior to ion implantation. Thus, it could be demonstrated that niobium is not only active when present in the bulk alloy, but also when located in the initially formed corrosion scale. Moreover, the implantation experiments revealed that the often suggested “doping mechanism” of the titania lattice by Nb⁵⁺ ions cannot play an important role explaining the beneficial effect of Nb. The morphology and composition of the scales formed during oxidation were studied by glow discharge optical emission spectroscopy (GDOES) and secondary neutral mass spectrometry (SNMS). The latter technique was also used in combination with two-stage oxidation experiments using the isotope tracers ¹⁸O and ¹⁵N.

Electrochemical characterisation of laser welding tracks by W.-D. Müller; H. Manthey; K.-P. Lange; H.-W. Gundlach; T. Plank (pp. 662-666).

The advantages of laser welding are high process velocity, the possibility to joint alloys, which are not solderable, and the high bonding strength. During the laser welding process a high energy input in a very short time and a small area is performed, resulting in possible changes of structure and composition. Direct information of the change of the electrochemical behaviour of dental alloys after Laser welding procedure does not exist. The aim of this work was, therefore, to assess the electrochemical behaviour of laser welded joints in comparison with the bulk material using the mini-cell system. The logI vs. E curves performed on the bulk material show a complete change concerning the characteristic data, the shape and the position in comparison to such curves measured on the laser track.The characterisation of the electrochemical behaviour of laser welding tracks seems to be very easy by using the mini-cell system.

Investigation of non-metallic impurities in High Speed Steel using SIMS imaging and scanning techniques by C. Brunner; H. Hutter; K. Piplits; M. Gritsch; G. Pöckl; M. Grasserbauer (pp. 667-671).

Non-metallic impurities or phases are often unintentional but important constituents in steel – they primarily influence the properties and behavior of the material by forming crystallization nuclei during the solidification process of the molten material. The kind, formation and spatial distribution of these inclusions has been investigated in this work by 2D SIMS, depth profiling and scanning SIMS. These non-metallic phases can be divided into oxides, nitrides, carbides, sulfides and gas bubbles. Probably the most important phase, the oxygenic, results from reactions of the molten bath with the ambient air and from the admixture of de-oxidation components. The investigated HSS specimen exhibits two different classes of inclusions. The first class mainly contains sulfide precipitates and differs widely from the second. The latter exhibits a spherical structure with the outer sphere combining the oxygenic precipitation and the core containing nitrides and sulfides. Due to the small size of the inclusions, they have been investigated by high resolution scanning SIMS to separate the different phases.

Atom probe study on the segregation behavior of the binary alloy Pt95Mo5 by A. Eckschlager; W. Athenstaedt; M. Leisch (pp. 672-673).

Atom-probe measurements have been carried out to study the segregation behavior of the binary alloy Pt95Mo5. On in situ annealed specimens a significant surface enrichment of molybdenum has been observed. Prolonged heat treatment results in a final Mo concentration of about 30 at.% extended about 2 nm into depth. This surface layer can be interpreted as the intermediate phase Pt₂Mo. The experimental result can be satisfactorily explained with the quasichemical model of Guggenheim.

In-situ observation of the nitrogenation of Sm2Fe17 by means of high temperature x-ray diffraction by Angelika Teresiak; Bernhard Gebel; Axel Handstein; Norbert Mattern; H. Klose; Karl-Hartmut Müller (pp. 674-676).

The mechanism of nitrogenation of Sm₂Fe₁₇ was investigated with in-situ high temperature x-ray diffraction with Debye-Scherrer optic using a quartz capillary equipped with an additional buffer volume to supply sufficient nitrogen for the expected phase reaction. The formation of Sm₂Fe₁₇N_x with x ≈ 3 was observed at temperatures between 325 °C and 450 °C. During the phase transition period, taking 30–90 min at 450 °C and up to 300 min at 350 °C, two phases were observed simultaneously, a non-nitrided Sm₂Fe₁₇ phase and the already fully nitrided Sm₂Fe₁₇N₃ phase. At 325 °C no single-phase material could be obtained during 300 min. The resulting lattice parameters measured after the complete nitrogenation are the same as those, obtained from the externally nitrogenized samples.

Characterization and application of supported metal catalysts with well-tailored pore systems and metal dispersions by P. Claus; Peter A. Crozier; Peter Druska (pp. 677-679).

Silica supported silver catalysts were prepared by sol-gel techniques and characterized by physisorption, in-situ ESCA measurements and transmission electron microscopy. Compared to conventional supported group VIII metal catalysts, these Ag/SiO₂ catalysts exhibited a superior performance for the selective hydrogenation of α,β-unsaturated aldehydes to allylic alcohols.

X-Ray absorption spectroscopy: sensitive characterization of (model-) catalysts with the electron yield technique by T. Schedel-Niedrig (pp. 680-682).

Small chromium oxide particles (Cr₂O₃, CrO₂) supported on titanium dioxide and oxidized Ag(111) single crystals were investigated by X-ray absorption spectroscopy at the oxygen K-edge. The spectra were collected in the electron yield mode in order to increase the surface sensitivity. The shape of the sharp split White line (WL) in the O K-edges spectra depended strongly on the oxidation state of the chromium ions in the probed samples suggesting that the WL can be used as an indicator of different environments in the supported chromium oxide films. On the other hand, the O K-edges of the oxidized Ag(111) crystal indicated that the formation of the distinct oxygen species at the surface and in the near-surface region was accompanied by a different silver-to-oxygen covalent interaction.

Electron probe microanalysis and magnetic characterization of compounds of the system Y-Ni-B-C by H. Szillat; P. Majewski; F. Aldinger (pp. 682-684).

Optimization of the conditions of electron probe microanalysis enables a quantitative determination of boron and carbon in compounds of the system Y-Ni-B-C. With this method boron deficiencies in YNi₂B₂C and solid solutions of carbon in Ni₂B and YNiB₄ were found. The number of boron deficiencies correlates with the T_c values of the superconducting transition in YNi₂B₂C.

Characterization of nanoscale metal structures obtained by template synthesis by F. Schlottig; M. Textor; N. D. Spencer; K. Sekinger; U. Schnaut; J.-F. Paulet (pp. 684-686).

Generating submicron objects made of nanostructured materials is one of the challenges of nanotechnology. A method for producing micron-sized structures without the use of lithographic techniques has been developed. Electrochemical deposition of metals into nanometer-wide parallel pores of porous anodic oxide films on aluminium is used to produce micro- to nano-wires or -tip arrays. The nanoscale structures and the structuring procedure have been investigated by the examination of lateral and cross-sectional specimens by SEM, EDS and XPS. The investigations show the feasibility of generating films with a variety of different compositions, a high density of tips, and tip diameters in the range of 30–150 nm. Furthermore, impedance spectroscopy was used to characterize the properties of the nanostructured surface. The results show a structure and composition dependent behavior due to the large (electrochemically) active surface area.

Microanalytical investigations on optical phase gratings in K(TiO)PO4 single crystals by R. Kriegel; Robert Wellendorf; Christian Kaps (pp. 687-689).

The Rb/K ion exchange in micro-structured K(TiO)PO₄ single crystals in contact with Rb containing nitrate melts results in ion-exchanged zones with enlarged refractive index which works as an optical phase grating. The knowledge of the diffusion behavior was the prerequisite for the generation of optimum refractive index profiles. Therefore, the local Rb/K concentration of ion-exchanged single crystals was determined with an electron probe microanalyzer (EPMA). The observed degree of ion exchange and the calculated Rb/K counterdiffusion coefficients were used to estimate the optimum ion exchange conditions. The diffusion-generated optical phase gratings show very narrow and deep ion-exchanged zones. The ratio of the ion penetration depths results in an extreme diffusion anisotropy D_Rb/K(c):D_Rb/K(b) ≈ 500:1.

SXPS analysis of passivation and complexation on the CdS (101¯ 0) surface by D. Mayer; K. H. Hallmeier; T. Chassé; R. Szargan (pp. 689-692).

CdS(101¯ 0) surfaces were chemically modified by oxidation in air or UV/ozone, sulfurization after treatment with a Br₂-methanol solution and reaction with the multidendate organic reactant 2-mercaptobenzothiazole (MBT). Surface sensitive photoelectron spectra from tuned excitation using synchrotron radiation (SXPS) show that initial oxidation by air gives monolayer coverages of sulfate (with minor contributions of sulfite) and chemisorbed polysulfur species passivating the surface. In contrast to this behavior the oxidation by UV/ozone proceeds very fast, giving thick sulfate layers. Thick layers of elemental sulfur are created during Br₂-methanol treatment. SXPS results show that a monolayer of chemisorbed polysulfide between the sulfur coverage and the sulfide is only removed by annealing the substrate up to 500 K. The reaction of MBT with the CdS surface is photochemically activated giving a submonolayer of MBT/adsorbate complex covered by bis(2-benzothiazolyl)disulfide (BBTD). A scheme of the photoinduced oxidation mechanism creating the disulfide is proposed.

Submonolayer detection of polymer additives at the surface of industrial products by R. Dietrich (pp. 692-694).

The TOF-SIMS technique was successfully applied for solving problems in the polymer coating industry. Submonolayer quantities of additives and contaminants segregated to the surface of polycarbonate automotive parts can cause heavy coating defects. These substances can easily be detected and identified by means of high resolution TOF-SIMS.

Polarization sensitive in situ infrared spectroscopy: the adsorption of simple ions at platinum electrodes by Michael Bron; R. Holze (pp. 694-696).

The application of a simplified spectrometric setup to the investigation of the electrochemical double layer using polarization sensitive in situ infrared spectroscopy is described. As examples, the adsorption of carbon monoxide, thiocyanate, and cyanate at platinum electrodes are investigated. Results are compared with previously published data. Differences are explained in terms of different experimental conditions, they are not caused by differences between the employed methods.

Surface analysis of titanium based biomaterials by R. Born; D. Scharnweber; S. Rößler; M. Stölzel; M. Thieme; C. Wolf; H. Worch (pp. 697-700).

The objective of the present study was the defined preparation and characterization of various oxide layers on titanium, Ti6Al7Nb and Ti6Al4V. Immobilization techniques for collagen and hydroxyapatite Ca₁₀(PO₄)₆(OH)₂, the main components contacting an implant within the human body, were tested. The oxide layers were created by electrochemical polarization in phosphate buffer solutions. The thickness of the layers depended on the formation potential. We found a thickness/potential relation of approximately 2.2 nm/V. At formation potentials up to 80 V anatase was the only titanium dioxide modification traceable by Raman spectroscopy and XRD. The electrochemically assisted deposition of hydroxyapatite on these surfaces starts with an amorphous product which can be monitored by SEM, IR and Raman spectroscopy. The immobilization of collagen followed by anodic electrochemical polarization results either in partial integration of collagen fibrils into the oxide layer or at least in a strong increase of the interaction force between TiO₂ and the collagen fibrils.

SEM-, EDS- and GDOES investigations for the identification of historical ferrous ore and slag from Sternmühlenthal valley in the outskirts of Chemnitz by D. Dietrich; P. Heger; E. Bäucker; G. J. Nuys; T. Grafe; G. Urban (pp. 701-703).

SEM, EDS and GDOES investigations on ferrous ore and slag samples contribute to the local history of mining and metallurgy. Quantitative X-ray analysis confirms the ore to be limonite. The slag consists of fayalithe and incompletely reduced ore parts (iron scale). Additional calcium and charcoal inclusions were reactants of the bloomery process. The charcoal shows anatomical details of spruce (Picea abies (L.) Karst.). A multitude of typical trace elements was detected by GDOES both in ore and slag samples. The comparison of normalised GDOES signals for a series of constituents showed that the ore from the assumed deposit (Euba) was processed in the location (Sternmühlenthal), where the slag was discarded. The process was probably performed in the 17th century.

Rapid soil analyses of overburden material from historic mines with SNMS by J. Goschnick; M. Sommer (pp. 704-707).

Plasma-based Secondary Neutral Mass Spectrometry (SNMS) is designed and usually used for depth-resolved determination of the elements in inhomogeneous samples. This report shows that it is also advantageous for the quantification of the total elemental inventory of granular material. As an example of such an application, the quantitative elemental analysis of soil samples from residues of three historic mines in Baden-Württemberg is presented. The results obtained with SNMS, using a high primary energy of E_p = 1340 eV, were compared to the concentrations measured by Atomic Absorption Spectroscopy (AAS) and X-Ray Fluorescence (XRF). A reasonable correspondence was found with a mean deviation between all three methods of about 50%. However, SNMS measurements of standard soils, without any matrix adaptation of the elemental sensitivities, exhibited mean deviations from the certified concentrations of only 20–30 wt% down to concentrations below 10^–2 wt%. The advantages of SNMS against AAS and XRF are its simple sample preparation and the rapid detection of all elements in the analyzed material within some 10 min. In each of the three samples chromium, nickel, copper, zink and lead (only sample HS 64) were found in concentrations exceeding the limiting values of the German Sewage Sludge Ordinance (SSO).

The depth distribution of organic additives in mortar measured with plasma-based Secondary Neutral Mass Spectrometry by J. Goschnick; U. Mäder; M. Sommer (pp. 707-709).

Amino alcohols (AMA) have been found to be successful in corrosion prevention of steel-reinforced concrete [1]. However, to work effectively the amino alcohol has to be located at the interface between the concrete and the steel rods reinforcing the stability of the building material [2]. Corrosion prevention for new buildings is easy because the corrosion inhibitor has already been added to the liquid concrete mixture and thus can easily reach the steel rods. With subsequent corrosion prevention measures for existing buildings, however, the problem of transport of the corrosion inhibitor through the solid concrete to the steel surface has to be solved first. In order to determine penetration, transport behavior, and transport rate, an AMA was applied to one face of rectangular mortar blocks used as model samples. A certain period of time for dwelling was given to allow the AMA to penetrate into the mortar. Moreover, the influence of the ambient humidity during the application was investigated. The analysis of the mortar was made by Secondary Neutral Mass Spectrometry, a technique used for the first time for this type of material because of the easy sample preparation, short analysis time, and high sensitivity.

Matrix sensitivity of solid sampling AAS. Determination of zinc in geological samples by K. Danzer; W. Schrön; B. Dreßler; K.-U. Jagemann (pp. 710-713).

Direct solid sampling techniques in AAS have several advantages over wet digestion methods such as small sample size requirements and simple calibration procedures. But some disadvantages also exist such as the sample in homogeneity and the matrix sensitivity of calibration. The calibration is commonly carried out by varying the sample mass and evaluating the peak intensity versus absolute analyte amount. It is shown here that this procedure must be considered doubtful when matrix effects are expected. In the case of zinc determination in geological samples it has been shown that calibration functions obtained by different reference materials differ significantly from each other. As an alternative a three-dimensional calibration technique can be applied that evaluates the peak intensity versus both analyte content and sample weight. The resulting calibration planes are expected to be hyperbolically curved. This three-dimensional calibration has been applied to the determination of Zn in geological samples and compared with classical solid sampling AAS calibration procedures.

Fluorine profiles in Antarctic meteorites by nuclear reaction analysis (NRA) by K. Noll; M. Döbeli; U. Krähenbühl (pp. 713-715).

Terrestrial fluorine enrichment on Antarctic meteorites can be measured by detection of γ-rays from the nuclear reaction ¹⁹F(p,αγ)¹⁶O, which is induced by a scanning proton beam. The technique (Nuclear Reaction Analysis by Proton Induced Gamma Emission: PIGME-NRA) allows simultaneous measurement of distribution and concentration without any chemical sample treatment and is not destructive. By using two detectors (HPGe and NaI) and taking into account the background contribution of the main interfering elements, the detection limit is below 10 μg/g. The information obtained allows to estimate the maximum exposure duration of meteorites on the Antarctic ice surface.

In-situ investigation of aerosol particles by atomic force microscopy by G. Köllensperger; G. Friedbacher; M. Grasserbauer (pp. 716-721).

In-situ imaging of aerosol particles deposited on mica in the TM-AFM liquid cell has been performed in order to study their dissolution behavior. The results show that the implementation of in-situ experiments is very useful for obtaining information on the physical and chemical behavior of individual particles. Experiments were carried out using ammonium sulfate and soot-like particles as test aerosols. Water soluble fractions can be easily distinguished from insoluble fractions. This can also be utilized to proof the existence of internally mixed particles. These model experiments are an important basis for further investigations on airborne particles involving other solvent systems and time resolved measurements.

New software tools for visualization of analytical data by M. G. Wolkenstein; H. Hutter; M. Grasserbauer (pp. 722-724).

Efforts towards using advanced computer graphics for improved visualization of three-dimensional (3-D) secondary ion mass spectrometry (SIMS) data are described. The application of the Visualization Toolkit (vtk), a freely available C++ class library for 3-D graphics and visualization for both PC and Unix systems, is demonstrated. Various available algorithms are used to analyze and visualize features otherwise hidden within data. A selection of examples is presented to demonstrate the capabilities of data visualization.

Structure analysis of [Be(NCS)2(C5H5N)2] by H. Böhland; W. Hanay; M. Noltemeyer; A. Meller; H. G. Schmidt (pp. 725-728).

[Be(NCS)₂(C₅H₅N)₂] was prepared and characterized by chemical analysis, FT-IR-analysis, and single crystal X-ray structure analysis. The crystals are orthorhombic with a = 829.30(10) pm, b = 1292.1(2) pm, c = 1313.40(10) pm, space group Pnma. Z = 4. The structure is built up from tetrahedra. Hydrogen bonding between the S-atom of one Be-N-bonded thiocyanate and 1.3-H-atoms of pyridine ligands yield a three dimensional network consisting of folded sheets.

Investigation of divergent beam X-ray reflex sections especially indication by computer simulation and assignment to the grains in polycrystalline samples by E. Langer; S. Däbritz; R. Kurt; W. Hauffe (pp. 728-732).

The divergent beam X-ray interference (DBI) method is commonly used to determine crystal systems, crystallographic orientation and lattice constants of single crystals and large individual grains and to get information on the real structure. Here back reflection divergent beam X-ray interference patterns (Pseudo-KOSSEL technique) were taken from polycrystalline specimens in the SEM and compared with corresponding lattice source interference (LSI) patterns (KOSSEL technique). A simulation program (for DBI) was developed allowing the calculation and indication of the complete reflex system as well as reflex sections. Reflex interruptions were obtained and could be explained by grain boundary effects. The influence of different important parameters such as the distance beween the target and the specimen, the target material, the orientation, the position, the shape and the size of the grains were discussed. Conclusions with respect to a local assignment of interruptions to grain boundaries are drawn so that now there is a possibility to localize the observed crystal defects.

Electrolytic hydride generation electrothermal atomic absorption spectrometry – in situ trapping of As on different pre-conditioned end-heated graphite tubes by E. Denkhaus; A. Golloch; T. U. Kampen; M. Nierfeld; U. Telgheder (pp. 733-737).

An automated analytical system for the determination of As combining an electrolytic hydride generator and a graphite furnace atomic absorption spectrometer has been developed. To investigate the trapping efficiency of permanent modifiers, the end-heated graphite tubes have been impregnated with Ir and mixed Pd/Ir pre-reduced modifiers, respectively, or pre-coated with Ir by electron beam evaporation under high vacuum. Furthermore, the influence of the modifier mass on the shape of the absorption signal has been studied and the performance of the modifier has been discussed. Using the pre-coated graphite tube the calculated detection limit (3s criteria ) for As was 3 pg and 15 ng/L (200 μL sample volume, two preconcentration steps) for the absolute mass and the concentration, respectively. The long-term stability of the permanent modifiers and their physical and or chemical changes during the lifetime of the tube have been observed.

On tertiary BOx± ions in HF-plasma SNMS by H. Jenett; Vasile-Dan Hodoroaba (pp. 737-740).

The effect of plasma electron impact on negative secondary ions is investigated by example of a sputtered H₃BO₃/Cu powder pellet. O^–, BO^–, BO⁺, and B⁺ tertiary ions, fractured from strongly forward focussed secondary BO₂ ^– ions, are identified by their kinetic energies. Since most of them are accepted by the ion optics, this process may affect quantification in HF-plasma SNMS.

Investigations of the solid state reaction process in mechanically alloyed Zr-Al-Cu-Ni bulk metallic glasses by analytical transmission electron microscopy by M. Seidel; M. Reibold; J. Eckert (pp. 740-742).

Starting with elemental powders, the progress of amorphization in mechanically alloyed Zr₆₅Al_7.5Cu_17.5Ni₁₀ has been investigated by x-ray diffractometry and transmission electron microscopy (TEM). Detailed investigations of the microstructural evolution during milling indicate that the amorphization proceeds by solid state reaction, similar to other well known binary or multicomponent systems.

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Analytical and Bioanalytical Chemistry (v.361, #6-7)

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Analytical and Bioanalytical Chemistry (v.361, #6-7)