bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silica coatings on α‐alumina particles: Analysis and deposition mechanism
Authors: Firment Lawrence E. , Bergna Horacio E. , Swartzfager Dennis G. , Bierstedt Paul E. , Van Kavelaar Michael L. 
Published: December 2004

AbstractCoatings are applied to particulate materials to enhance surface properties while retaining desired bulk properties. Characterization of such coatings presents a challenge. In this paper we present an example of a particle surface analysis and assess how factors such as roughness and coating thickness distributions affect quantitative conclusions. Silica coatings were deposited from aqueous solution on to α‐alumina particles of 150 nm average size. Transmission electron microscopy, x‐ray photoemission spectroscopy and secondary ion mass spectrometry/depth profiling were used to analyze coatings of thicknesses of tens of nanometers to submonolayer. The three techniques were in excellent agreement in the thickness ranges where they overlapped. XPS does not allow assessment of the uniformity or thickness distribution of the coatings. However, depth profiles are quantitatively consistent with a model of random attachment of the silica units to the particle surface during growth, with no preference for the uncoated alumina surface over the previously deposited silica.
The interaction of lithium with sodium and potassium silicate glasses
Authors: Maschhoff B. L. , Armstrong N. R. 
Published: December 2004

AbstractThe interaction of lithium with sodium and potassium glass surfaces in UHV has been characterized with XPS. Earlier studies of the Li/SiO2 system have shown the formation of a partially passivating layer upon initial Li deposition. Following breakdown of this layer, substantial reduction of the glass matrix occurs. In the present study, several compositions of sodium silicate and potassium silicate glasses were found to be more resistant than SiO2 to lithium attack owing to the presence of non‐bridging oxygens in the matrix. The proposed corrosion mechanism involves charge transfer from Li to the modifying cations at the glass surface followed by desorption of neutral Na or K and interdiffusion of Li+ into the glass. For thick (metallic) Li films on sodium silicates, the formation of a dilute Li—Na intermetallic and sodium metal are identified from distinct plasmon structure in the Na(1s) line. Matrix reduction of glasses with low alkali content has been observed subsequent to the atom exchange.
Auger depth profiling of polycrystalline metal films using Xe+ and N2+ ions
Authors: Tanemura M. , Fujimoto S. , Okuyama F. 
Published: December 2004

AbstractPolycrystalline Al, Mo, Ag and Ta films deposited on mirror‐polished (100) Si wafers were Auger depth profiled using 3 keV Xe+ and N2+ ions as projectiles. In every case, Xe+ sputtering provided a less‐textured surface, and hence a higher depth resolution. This allowed us to conclude that the ion species better suited for practical Auger analysis is Xe+. Tantalum surfaces bombarded with N2+ ions were characterized by very tiny, densely distributed cones, in contrast with Ta surfaces exposed to Xe+ ions displaying no surface protrusion detectable by high‐resolution SEM. This finding was inexplicable by the traditional concept of ‘reactive ion sputtering’, thus the formation mechanism of these tiny cones is discussed. The result of Auger depth profiling of Mo film using Xe+−N2+ mixtures is also reported briefly.
Quantitative AES: Via the inelastic mean free path or the attenuation length?
Authors: Jablonski Aleksander 
Published: December 2004

AbstractThe terms inelastic mean free path (IMFP) and attenuation length (AL) of electrons in solids are described by different definitions and their values may differ profoundly, by >30%. For this reason, it is of crucial importance to decide which term should be used in calculations for quantitative AES analysis. An attempt to answer this question is made in the present work. The Monte Carlo algorithm was developed to simulate the Auger electron transport in metal alloys. Calculations were made for Auger electrons emitted in the Al48Ni52 ordered alloy and the corresponding standards. Comparison with the usual mathematical formalism of AES shows that elastic collisions of Auger electrons can be accounted for by two correcting parameters: (1) a correction denoted by Q, which accounts for the decrease of the Auger electron current; (2) a correction denoted by K, which accounts for the decrease of the depth of analysis. It was proved that the total correcting factor comprises four groups of parameters: atomic densities, back‐scattering factors, inelastic mean free paths and corrections Q. Thus, we obtain the unexpected result that the calculations for quantitative AES require knowledge of the IMFP rather than the AL. The parameter Q is usually close to unity and can be neglected. The use of attenuation lengths in calculations may result in considerable errors. However, it is possible to recalculate values for the AL to obtain the IMFP.
Quantitative analysis of impurities in SIMOX samples using secondary ion mass spectrometry
Authors: Chi P. H. , Simons D. S. , Roitman P. 
Published: December 2004

AbstractSilicon films produced by the SIMOX process (separation by implanted oxygen) must be annealed at high temperature to remove the crystal damage introduced during implantation of the high oxygen dose. Different annealing gases, temperatures and times have been investigated. In such processes, various impurities present in the hightemperature ceramic furnace tube, as well as annealing gas species, may be incorporated into the samples. Secondary ion mass spectrometry (SIMS) is used as a quantitiative tool to analyze the diffusion of tube components and gases into annealed SIMOX samples. Samples. Samples prepared for this investigation were annealed in nitrogen and argon at temperatures ranging from 1250 to 1350 °C. We found that most impurities are present at low levels and are generally trapped in the surface oxide that is grown during the anneal. SIMS analyses of SIMOX samples annealed in nitrogen showed that nitrogen tends to collect in both the surface oxide band buried oxide layers, piling up at the oxide/silicon interfaces.
Redox processes in polyaniline thin film studied by optical multichannel analysis
Authors: Bernard M. C. , Hugot‐Le Goff A. 
Published: December 2004

AbstractOptical multichannel analysis (OMA) was used to follow the kinetics of colour changes in electrochromic polyaniline films when the latter are polarized in an electrolytic medium at different potentials. These colour changes, which are related to the transition from one polymer form to another, are very fast. OMA also allowed us to obtain an apparent value of the film absorption coefficient. In the investigated range (300–800 nm), several absorption phenomena can be displayed which are characteristic of the different polymer forms. Two electrolytic media (1 M HCl and 1 M H2SO4) were compared to investigate the role played by the size of the inserted counter‐ion. The overall results allow us to estimate the practical possibility of using polyaniline in electrochromic devices.
Application of transmission Mössbauer effect spectroscopy to the study of electrocatalysis and adsorption phenomena at the nickel hydroxide electrode
Authors: Kamnev Alexander A. , Ezhov Boris B. , Rusanov Ventsislav , Angelov Venelin 
Published: December 2004

AbstractMössbauer parameters for ferric hydroxo forms in alkaline matrices, ferric oxyhydroxide and its admixture at the nickel hydroxide electrode surface as well as for ferric hydroxo species absorbed at nickel hydroxides from strongly alkaline solutions have been compared. The feasibility of transmission Mössbauer spectra acquisition for the adsorbed species in the presence of dissolved forms (e.g. in situ) is based on the principle that the latter give no Mössbauer effect at room temperature owing to their diffusional mobility, while the former, being fixed at the adsorbent surface, have been shown to exhibit a sufficient resonant absorption. The effects of adsorption and water have been noted. Some questions connected with anodic oxygen evolution electrocatalysis by iron species involved in the anodic process at the nickel hydroxide electrode are also discussed.
New entries in the XPS fingerprint database for the characterization of precipitated CuZnAl oxide catalysts
Authors: Grohmann I. , Peplinski B. , Unger W. 
Published: December 2004

AbstractDetailed x‐ray photoelectron spectroscopic data for Cu and Zn observed with well defined reagent grade malachite, precipitated (Zn, Al)‐hydrotalcite and precipitated (Cu, Zn, Al)‐hydrotalcite samples are presented. These data are compared with the respective results observed with CuO and ZnO. Moreover, literature XPS data characteristic of precipitated malachite, CuCO3 and Cu(OH)2 are used for comparison. Relevant copper and zinc data are presented as ‘chemical maps’. Certain results illustrate the analytical potential of a detailed analysis of the Cu2+ 2p satellite parameters which are known to be co‐ordination‐sensitive. The bulk co‐ordinations of Cu2+ and Zn2+ species in malachite, hydrotalcite, CuO and ZnO are briefly reviewed.
Applications of surface‐analytical techniques to aluminium surfaces in commercial semifabricated and finished products
Authors: Amstutz Markus , Textor Marcus 
Published: December 2004

AbstractThe application of surface‐analytical techniques (XPS, SIMS, SNMS) in an industrial R & D department of a company producing aluminium semifabricated and finished products is reviewed. Four different ‘case studies’ are presented related to: (a) composition of oxide films on aluminium foil of commercial purity influencing corrosion resistance and adhesion in packaging products; (b) control of thickness and composition of chromate conversion coatings; (c) surface factors influencing etchability of high‐purity aluminium foil for use in electrolytic capacitors; (d) electrochemical behaviour of AlMgGa alloys in alkaline electrolytes related to use as active battery anodes. Modern surface‐analytical techniques turn out to be a valuable instrument both for product development and problem solving related to surface and interface properties. Specific answers to problems can often only be given based on results of several analytical and structural techniques, including more ‘conventional’ techniques such as wet‐chemical trace analysis or electron microscopy of thin films.
Grain boundary segregation in [100] symmetrical tilt bicrystals of an FeSi alloy
Authors: Hofmann S. , Lejěek P. , Adámek J. 
Published: December 2004

AbstractThe orientation and temperature dependences of the segregation of P, Si and C at [100] symmetrical tilt grain boundaries of an Fe‐3.5 at.% Si alloy were determined by AES analysis ofin situfractured bicrystals. The obtained anisotropy of the segregation enthalpy of all three elements is characterized by its low absolute values for the {013} and {012} boundaries. Both of these boundaries belong to the low classification levels after Paidar and possess high values of interplanar spacing which can be used as a simple geometric criterion of the boundary ‘specialty’. The data are consistent with the construction of the grain boundary segregation diagram showing the dependence of the segregation enthalpy on both the boundary orientation and the maximum solid solubility of the solute.
On the oxidation of γ′‐Fe4N1−x layers; redistribution of nitrogen
Authors: Somers M. A. J. , Kooi B. J. , Sloof W. G. , Mittemeijer E. J. 
Published: December 2004

AbstractIron nitride (γ‐Fe4N1−x) layers produced by gaseous nitriding of pure iron in an NH3/H2 mixture at 843 K were gaseously oxidized at 673 K in pure O2. During oxidation an ε‐Fe2N1‐y layer developed between a magnetite (Fe3O4) scale and the parent γ′‐nitride layer. Porosity was observed in the oxide‐adjacent part of the ε‐grains. Scanning Auger microscopical analysis and electron probe microanalysis showed (1) that the occurrence of the ε‐nitride layer is associated with a locally higher nitrogen content, (2) that no nitrogen is incorporated in the oxide layer and no oxygen is dissolved in the nitride layer and (3) that a nitrogen concentration‐depth gradient occurs which corresponds to a change of about 1 at.% N over the thickness of the ε‐layer. From a thermodynamical point of view, formation of N2 gas during the oxidation of γ′‐nitride is more likely to occur than formation of ε‐nitride; the latter reaction appears to be kinetically favoured. Quantitative analysis of the nitrogen redistribution suggests that some of the nitrogen atoms released by conversion of γ′‐nitride into magnetite are transformed into N2 which is present in the pores near the oxide/nitride interface.
Application of glow discharge optical emission spectroscopy to diffusion measurement of copper in ferritic and austenitic iron and steels
Authors: Suzuki S. , Suzuki K. , Kurosawa F. , Kobayashi H. 
Published: December 2004

AbstractGlow discharge optical emission spectroscopy (GDOS) is a method to analyse the optical emission of elements during sputtering of a solid, providing data on the light intensities of the elements vs. the sputtering time. By correcting the measured light intensities with standard samples, it is possible to obtain the quantitative depth profile up to about 100 μm. In the present research, GDOS was applied to the diffusion measurement of impurity atoms in metals and alloys. After a thin film of copper was coated on iron and steels, the surface film was diffused into the matrix at high temperatures. The penetration curves of copper from the surface were obtained from the GDOS data. Diffusivities of copper in ferritic and austenitic regions of iron were determined from the penetration curves, which were in agreement with previous results. Diffusion of copper in commercial ferritic and austenitic stainless steels was also examined. The diffusivities obtained were comparable with those expected from the temperature dependence of the diffusivities in the ferritic and austenitic phases of pure iron.
Study of concentration–depth profiles in CoSi2 near‐surface layer after ion bombardment
Authors: Vojtusik S. S. , Borodyansky S. E. , Zaporozhchencko V. I. 
Published: December 2004

AbstractThe concentration–depth profiles of Co and Si were investigated in the CoSi2 (100) altered layer after attaining the sputtering steady state by Ar+ ions. The depth profiles were determined from angle‐dependent AES data. Independent measurements of the Co low‐ and high‐energy lines and the Si low‐energy line lead to the conclusion that the concentration–depth profile of elements is not monotonous within the altered layer.
Effects of flame treatment on propylene–ethylene copolymer surfaces
Authors: Sheng E. , Sutherland I. , Brewis D. M. , Heath R. J. 
Published: December 2004

AbstractThe effects of flame treatment on the surfaces of a propylene‐ethylene copolymer have been studied using XPS, contact angle measurement, vapour‐phase derivatization and an adhesion test. The results obtained were compared to those from the homopolymer. An optimum air‐to‐gas ratios of ∼11:1 has been found. Close correspondence between water contact angle and oxygen concentration was found, with the exception of high oxygen concentrations. The orientation or migration of functional groups away from the surface has been proposed to cause the non‐correspondence between water contact angle and oxygen concentration. Diiodomethane advancing contact angle was found to remain constant, independent of flame conditions. XPS analysis in conjunction with vapourphase derivatization with trifluroacetic anhydride (TFAA) suggests that up to 20% and 30% of the oxygen introduced in the surfaces is present as hydroxyl groups for propylene homopolymer and the copolymer, respectively. High adhesion levels of the flame‐treated copolymer with a polyurethane‐based paint were found. In most cases, the adhesion failure was complex, but involved the cohesive failure of the copolymer.
Enhancing the interpretation of x‐ray photoelectron spectra using numerical methods
Authors: Stickle W. F. , Sobol P. E. 
Published: December 2004

AbstractX‐ray photoelectron spectroscopy (XPS) has long been used as a surface analytical method for the determination of elemental composition and chemistry of a material. Small‐area analysis allows the comparison of different areas of a sample surface, while sputter depth profiling makes it possible to follow the specific chemistry as a function of depth. Often in XPS, peak overlap or subtle changes in chemistry may sometimes make the chemical‐state analysis of the elements in a material difficult. By using a variety of numerical methods, it is possible to enhance the analysis and interpretation of surface analytical data. Such numerical methods would include linear least‐squares and fitting and target factor analysis. By using these methods it is possible to enhance the chemical‐state interpretation and in many cases significantly increase the detection limits of specific elements. Several examples of the application of numerical methods are used to illustrate the enhancement of data interpretation of XPS data, with special emphasis on linescans and sputter depth profiles.
Bethe ionization cross‐sections: A quantitative survey on calculating the backscattering factor in AES
Authors: Lee C. L. , Ong C. K. 
Published: December 2004

AbstractThe objective of this work is to investigate the usefulness of the Bethe cross‐section with Powell parameters for possible future use in quantitative AES. The Powell energy‐dependent parameters are obtained from a least‐squares fit to various experimental and calculated work on ionization cross‐sections and are proven to have an accuracy of better than about 1% for Unl > 4 (Unl = E0/Enl), where E0 is the incident electron energy and Enl is the binding energy of the electrons in the nl‐shell. This cross‐section was quantum mechanically derived from the first Born approximation by Bethe and its use can be extended to lower‐energy ranges as evidenced from the Fano plots available. This means that the cross‐section has the advantages of a closer fit to experimental data and is within the energy range of interest in AES. A simple Monte Carlo approach has been adopted to calculate the backscattering factor and related Auger intensity lines using this cross‐section for C, Si, Cu and Ag elements. Results compared with both recent experimental data and Gryzinski cross‐section results indicate strongly that the Bethe cross‐section can be used for future quantitative analysis in AES.
Activities of the ASTM committee E‐42 on surface analysis
Authors: Powell C. J. 
Published: December 2004

AbstractThe ASTM Committee E‐42 on Surface Analysis was formed in 1976 to advance the field of surface analysis and the quality of surface analyses through the development of appropriate standards (reference procedures, reference materials and reference data), round robins, symposia, workshops and publications. A major function of the Committee is the development of documentary standards or reference procedures. This article contains a brief summary of Committee activities, with emphasis on the reference procedures that have been published and those that are under development.
Evaporated and implanted reference layers for calibration in surface analysis
Authors: Wätjen U. , Bax H. , Rietveld P. 
Published: December 2004

AbstractThe potential of thin reference layers prepared by the Central Bureau for Nuclear Measurements, especially for calibration puposes in surface analysis, is presented. Our special preparation procedure is outlined, making use of an ultrahigh vacuum microbalance with the substitution principle of weighing applied. Our procedure of chracterizing the areal density of the evaporated layers is unique in that it provides for an optimal traceability to the SI unit of mass. Besides thin metal layers evaporated onto vitreous carbon substrates, which can serve for yield calibration in surface analysis, we are making use of thin layers as internal standards on implanted samples in order to perform high‐accuracy determinations of the retained dose through Rutherford backscattering spectroscopy. After sensitive tests of the thickness uniformity, evaporated and implanted thin layers are made available as reference samples.
Correlation of the emission of SIMS cluster ions with composition and structure from the Al2−xCrxO3 Mixed Oxide Series
Authors: Reed Nicola M. , Vickerman John C. 
Published: December 2004

AbstractThe Al2−xCrxO3 mixed oxide series demonstrates that as the composition of the oxide is varied then the distribution of secondary ion clusters is also observed to change. A general model has been proposed to account for these variations in the formation of secondary cluster ions.It has been shown that at very low chromium concentrations (0–0.1 mole fraction Cr) the incorporation of chromium into the Al2O3 lattice, forming a solid solution, results in an increase in the Al‐O bonding as manifested by the increase in the AlO+ and AlO− species concurrent with the reduction in the Al2+ and Al2O2+ clusters.At increasing concentrations of Cr (0.1–0.4 mole fraction Cr) these appears to be an increase in the AlO and CrO bonding. This increase is thought to be due to the development of the localized CrCr bonding. This is shown by the increase in the AlO2− and the AlO4− clusters, whilst the influence of the localized bonding is demonstrated by the increased Cr2O+ species. Ther is a decrease in any clusters containing both Al and Cr which is explained in terms of the preference of the chromium to be emitted as part of a chromium pair in this composition range.At further increased concentrations of Cr (0.4–1.0 mole fraction Cr) a chromium sub‐lattice begins to develop. This formation reduces the localized CrCr bonding which was noted at the lower chromium concentrations, which in turn results in a more delocalized bonding within the chromium lattice. This effect is indicated by the increase in the AlCrOx+ species.The relative intensities of these cluster ions throughout the composition range, are also shown to reflect the changing oxidation state of the composite oxides across the series.
High‐energy LMM Auger transitions
Authors: Weisz S. Z. , Gomez M. , Resto O. , Many A. , Goldstein Y. 
Published: December 2004

AbstractWe have recently shown that with the commonly available resolution in Auger electron spectroscopy measurements, significant errors can be incurred in the measured Auger line intensities. To overcome this difficulty, a universal relation has been derived theoretically whereby the experimentally measured line intensities can easily be corrected so as to yield good estimates for the true intensities, i.e. those that would have been measured were the resolution infinitely good. The validity of our correction procedure was recently demonstrated for the high‐energy KLL and low‐energy LMM lines of Si, Al and Mg as well as for the high‐energy LMM and low‐energy MNN lines of Cu. In this paper we extend these studies to the high‐energy LMM lines of Zn, Ge, Fe, Co and Ni. We present here the intrinsic lineshapes of these lines as well as the Auger sensitivities relative to silver, measured with different resolutions. The correction procedure applied to the data yields the true sensitivities to a good approximation and is therefore important for quantification and for theoretical calculations of Auger Yields.