bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of XPS to the surface analysis of yeast cells
Authors: Amory D. E. , Genet M. J. , Rouxhet P. G.
Published: May 2005

Yeast cells, Saccharomyces cerevisiae and carlsbergensis, have been analysed by XPS.

A preparation and analysis procedure was developed in order to minimize contamination and re‐arrangements of the cell surface. The use of an external standard of silica permitted the absolute surface concentrations to be estimated and the influences of sample preparation procedure on surface roughness and chemical composition of the cell surface to be evaluated separately. The selected procedure consisted of washing the cells in distilled water, freezing a pellet in liquid nitrogen, freeze‐drying at 268 K, mounting the obtained powder in a trough and pressing the surface.

Repeated analyses on a given yeast strain enable the variances linked to the main steps of the preparation procedure for each surface element to be evaluated; thereby, confidence intervals can be given for any small set of XPS data. Freeze‐drying is the main source of variation and samples which have to be compared should be freeze‐dried together. The reproducibility of the surface concentration decreases in the order C, O, N, P and is much better for the N/P ratio than for N or P alone.

The neutrality of the XPS preparation and analysis procedure towards the yeast cell surface is supported by the correlation obtained for ten yeast strains between the surface N/P ratio (dehydrated state) and the electrophoretic mobility at pH 4 (hydrated state). This gives confidence in the ability of XPS to investigate a biological surface. The surface specificity of XPS is illustrated by the very low O/C (0.39) and N/C (0.1) concentration ratios which denote a high proportion of lipids at the cell surface (60–70%), in contrast with the low proportion in the whole cell wall (8%).
XPS analysis of oxides
Authors: Paparazzo E.
Published: May 2005

The principal scope of this work is to explore the capacity of XPS spectroscopy in the characterization of oxides through consideration of O 1s spectra. Several examples of oxides, analysed both separately and in the form of mechanical mixtures, are reviewed. The quantitative aspects involved in the XPS analysis of oxide mixtures were studied by use of an approach based on intensity ratio measurements of the single O 1s components.

Results obtained in the mixtures are utilized for establishing the presence, or otherwise, of a single oxidic phase at real interfaces of iron‐alumina systems, metallurgical coatings, and glasses.
Sample preparation effects in the surface analysis of V/Ti alloys
Authors: Dawson P. T. , Hu M. P.
Published: May 2005

The surface composition of V–21% Ti alloy as revealed by Auger electron spectroscopy becomes depleted in Ti on bombardment with 2‐kV argon ions. Alloy composition changes by preferential sputtering are frequently observed, but what is surprising in this case is that a steady‐state composition is not achieved until after ca. 8 h of sputtering. Experience with other alloy systems has been that steady state is attained in minutes; furthermore, it is difficult to conceive an atomic process which would account for such slow composition changes. The alloys was prepared by monoarc co‐melting of the pure metals, slicing with a slow‐speed diamond saw and mechanical polishing down to 1 μ diamond. The polishing damage will extend several micrometres below the sample surface, which is consistent with the thickness of sample removed by 8 h of ion bombardment. A possible model is provided by radiation induced segregation, where the defects created by ion bombardment of the alloy annihilate at both external and internal surfaces associated with polish damage. At the beginning of the sputtering, the internal surface provides the dominant sink, whereas after the polish damage has been entirely removed this is provided by the external ‘analysed’ surface. This interpretation was tested by preannealing a freshly polished specimen to remove the polish damage before sputtering. In this case, the steady‐state composition was attained in minutes, as predicted by the model. One final question concerns the absence of such effects in other systems, e.g. W/Mo, Cr/Mo. The answer can probably be found in the different room temperature mobilities of the ion‐bombardment‐induced defects in such refractory alloys when compared with V/Ti. This is supported by the composition changes observed on ‘room temperature annealing’ when bombardment of V/Ti is stopped, an effect never observed in the refractory alloys.
Electron‐stimulated desorption, secondary emission and charging of ionic crystals
Authors: Atabaev B. G. , Besedina E. A. , Kareev M. S. , Dzabbarganov R.
Published: May 2005

Negative and positive charging of ionic monocrystals (KCl, NaCl, Al2O3, MgO, SiO2 and LiH) under low‐energy electron irradiation is investigated by AES and mass spectrometry. Secondary emission and electron‐stimulated desorption negative ions of LiH data are presented. The mass spectra of sputtered neutrals post‐ionized into negative ions, and their ionization coefficients on the auxiliary target with a low work function, are presented. A phenomenological model of charging of dielectrics that depends on defect formation and secondary emission properties under low‐energy electron irradiation is presented.
Surface analysis to study the improvements of silicon nitride/gallium arsenide interface properties
Authors: Cassette S. , Plais F. , Olivier J.
Published: May 2005

It has been shown that NH3, plasma treatment of GaAs surfaces before deposition of plasma‐enhanced chemical vapour deposited silicon nitride significantly improves the SiNH/GaAs interface properties. The decrease of surface state density together with the increase of Fermi level excursion in the energy gap are correlated with chemical spectroscopic measurements.
Standard reference spectra for XPS and AES: Their derivation, validation and use
Authors: Smith G. C. , Seah M. P.
Published: May 2005

A principal requirement for quantitative AES and XPS is the ability to measure true spectral intensities. In order to achieve this we have developed a fully instrumented electron spectrometer to measure absolute intensities for AES and XPS. The spectra contain no distortion due to the energy dependencies of the analyser transmission or the detector efficiency, and therefore provide the true spectrum n(E) with a known uncertainty. In addition, the intensity scale is known accurately in terms of electrons detected per unit of incident flux. The experimental methods and theoretical basis used in the determination of standard reference spectra are discussed, and results are presented for both Auger electron and x‐ray photoelectron spectroscopies. AES or XPS spectra of NPL reference materials taken on any user's instrument, with the appropriate conditions, may be compared with the true spectra derived here to calibrate the energy dependence of that particular instrument's intensity scale. In this way, all instruments may be calibrated absolutely to an accuracy of ±2%.
Back‐scattering and X‐ray‐induced correction factors for AES of thin overlayers: Influence on lateral resolution
Authors: Valamontes E. , Nassiopoulos A. G. , Glezos N.
Published: May 2005

Some results on Monte‐Carlo calculations of back‐scattering and x‐ray‐induced correction factors for AES on thin overlayers have been given in a previous paper. In this work, further results are given concerning both correction factors and the lateral resolution in the primary beam energy range 5–60 keV. The x‐ray‐induced correction factors include both characteristic and continuous x‐rays created in the bulk by the primary electron beam or by back‐scattered electrons that contribute to the creation of Auger electrons within the film on their way out of the sample. The contribution of continuous x‐rays, negligible at low primary beam energies, is found to be important at energies of >20 keV. The influence of back‐scattering on the lateral resolution in the primary beam energy range 20–60 keV has also been studied.
Influence of nickel on the behaviour of superferritic 290 Mo alloys in sulphuric and hydrochloric acid media: XPS, AES and electrochemical studies
Authors: Traisnel M. , Elachab M. , Gengembre L. , Leroy J. M.
Published: May 2005

Impedance and potentiodynamic polarization measurements show that the addition of nickel to superferritic 290 Mo alloys improves their resistance to the corrosion process in sulphuric acid and plays a disastrous part in hydrochloric acid. The chemical composition, thickness and depth profile of the passivating layers obtained in sulphuric acid are determined by using XPS and AES. In the anodic polarization domain, chromium oxide is the major component of the passivating layers and the addition of nickel increases its segregation slightly. In the cathodic polarization domain, the addition of nickel leads to passivating layers that are clearly more developed. Chromium oxide is no longer the major component, and an important segregation of molybdenum oxide and, to a lesser extent, nickel oxide towards the uppermost layer is observed.
Surface analysis of uranyl fluoride layers with a glow discharge lamp
Authors: Nel J. T. , Stander C. M. , Böhmer R. G.
Published: May 2005

Surface analysis with a Grimm‐type glow discharge lamp was used to analyse uranyl fluoride layers that had formed on a nickel sufbstrate after exposure to UF6. Narrow‐band optical filters were used to isolate the intensities of three fluorine emission lines. An in‐depth profile of layer composition was obtained.
Surface characterization of coated powders: Al2O3SiO2‐coated TiO2
Authors: Johansson Leena‐Sisko , Losoi Tuomo
Published: May 2005

The aim of this study has been to find experimental strategies to characterize surface of coated powders. We have studied hydrous alumina + silica‐coated TiO2 pigments using different XPS methods, isoelectric points (ieps) and x‐ray fluorescence (XRF). We tested especially the applicability of a simple XPS analysis method introduced by Tourgaard et al.

Coated TiO2 powders were analysed qualitatively with ieps, XPS surface concentrations, XPS depth profiling, and Ti 2p photoemission peak‐to‐background ratio D, The ratio D together with surface concentrations, was found to characterize well the quality of the coating. Differences in surface layers were affirmed also by ieps and XPS profiling.

The asymptotic value of D for uncoated, uncontaminated TiO2 powder, interpolated from qualitative results, was ∼25 eV. This is within 25% of the predicted universal constant (25.2 eV) for transition metals and alloys.

Coating layer thicknesses were calculated from XRF and XPS data, the latter assuming an exponential attenuation model with superficial carbon. Based on the value of D, Ti 2p photoelectron mean path lengths (R) also were calculated from the experimental equation by Tougaard. We found good correlation between the results from conventional XPS layer calculations and the Tougaard equation. The methods are independent of each other. Together, they seemed to give more reliable information on the non‐ideal powder surfaces studied than either of the methods alone.
Ion–solid interaction at low energies: Principles and application of quantitative ISS
Authors: Niehus Horst , Spitzl Ralf
Published: May 2005

Quantitative surface analysis with low‐energy (500–5000 eV) ion scattering is known to be difficult, most often because of strong charge transfer and multiple scattering effects occurring during ion–surface interaction. In order to avoid neutralization problems, either alkali primary ions or noble gas ions in combination with the detection of all scattered particles was applied. Multiple scattering occurs predominantly at forward scattering and might confound the analysis. Backward scattering (i.e. 180° impact collision ion scattering) bypasses strongly the multiple scattering complication and has been used successfully for the analysis of a number of surface structures for metals, semiconductors and binary alloys. Quantitative surface structures were determined by comparison with computer simulations.
Testing epoxy composite surfaces for bondability
Authors: Parker Brenda M. , Waghorne Rex M.
Published: May 2005

Composite surfaces before and after pretreatment for adhesive bonding have been examined by x‐ray photoelectron spectroscopy (XPS) and the extent of transfer of release agents or other contaminants from release agents, which also were analysed by XPS, was estimated. Composite surfaces were examined also by optically stimulated electron emission (OSEE). Surface analyses were correlated with the strengths of adhesive bonded joints. OSEE shows promise as a non‐destructive method for determining the bondability of epoxy resin matrix composites.
Modification of polypropylene surfaces by flame treatment
Authors: Sutherland I. , Brewis D. M. , Health R. J. , Sheng E.
Published: May 2005

The changes induced on the surface of polypropylene homopolymer following flame treatment have been studied. Surface compositions were determined using x‐ray photoelectron spectroscopy and compared to surface free energies estimated from contact angle measurements. The effect of air‐to‐gas ratio, total flow rate, contact time with the flame and the distance between the inner cone tip of the flame and the polymer have been investigated. Mild flame treatments were found to be effective in promoting the adhesion of polyurethane paints to the polypropylene. The adhesion between flame‐treated polypropylene and the paint film was assessed using a composite butt test and the measured bond strengths were found to be well in excess of those obtained using solvent wiping or chlorinated polyolefin primers.
Analysing coated powders with XPS
Authors: Johansson Leena‐Sisko
Published: May 2005

The goal for this study has been to show how different XPS analysis methods may be used in the characterization of coated powders. An inhomogeneous powder system serves also as an example of inhomogeneous uneven samples in general.

The XPS methods discussed here are: elastic peak measurements and the layer calculations derived from them; depth profiling by sputtering or by verying the analysing angle; and analysis of both elastic and inelastic parts of an XPS peak by methods introduced by Tougaard et al. Correlations between the results from different XPS methods are also discussed.

As an example, XPS methods were applied to the surface characterization of real coated TiO2 pigments. XPS results are also compared both with XRF bulk analysis and with each other.
Quantification of carbon in MOVPE‐grown AlAs on GaAs substrates using SIMS
Authors: Maydell E. A. , Fabian D. J. , Roberts J. S.
Published: May 2005

Concentrations of carbon in layer of metal organic vapour phase epitaxy (MOVPE)‐grown AIAs on GaAs substrates were determined by SIMS using a Cs+ primary ion beam. The measurements demonstrate that by using an ultrahigh vacuum (UHV)VG quadrupole‐based SIMS instrument and thorough outgassing of samples, sputter etching conditions can be established that give C− signals unaffected by residual gas interference, while maintaining good depth resolution.
XPS valence band analysis of plasma–treated polymers
Authors: Foerch R. , Beamson G. , Briggs D.
Published: May 2005

The valence bands (VB) of remote oxygen and remote nitrogen plasma‐treated polyethylene and polypropylene were studied to determine changes in the basic polymer structure. Each of the polymers showed a characteristic valence band profile, which retained much of its original shape after plasma treatment. This has suggested that even though plasma treatment can cause the incorporation of a high proportion of functional groups, significant segments of the original polymer structure remain unchanged within the x‐ray photoelectron spectroscopy (XPS) sampling depth. Angle‐resolved x‐ray photoelectron spectroscopy (ARXPS) suggests that near the outer surface, the polyethylene structure is modified by branching and cross‐linking.
Effect of different cooling rates on Cr segregation and determination of the equilibration time of Cr segregation in CoOCr2O3 and NiOCr2O3 solid solutions
Authors: Hirschwald W. , Stolze F. , Sikora I.
Published: May 2005

CoO and NiO single crystals doped with chromium were either quenched or slowly cooled after 1 week of annealing at 1150° C and 1200° C in argon. SIMS analysis of the Cr surface distribution revealed a remarkably high Cr concentration in the near‐surface layers of slowly cooled samples and a much smaller concentration for the quenched crystals. The differences of surface Cr concentration in various quenching procedures are also shown.

By applying subequilibrium annealing times, different Cr segregation levels and varying thicknesses of surface layers could be established. The time of annealing necessary to obtain equilibrium of segregation was determined for both solid solutions.
Surface modifications introduced to a polytetrafluorethylene‐filled polycarbonate compound by dry sliding against steel as revealed by imaging XPS
Authors: Fletcher I. W. , Davies M. , Briggs D.
Published: May 2005

Imaging XPS has been used to study surface modifications in a polytetrafluoroethylene (PTFE)‐filled polycarbonate compound as a result of dry sliding wear testing. The novel observation of the formation of a PTFE film over the polymer compound surface (in addition to a transfer film on the steel counterface) will be of significance to the understanding of friction and wear mechanisms and to the performance of polymer systems in tribological applications.
The determination of uncertainties in quantitative XPS/AES and its impact on data acquisition strategy
Authors: Harrison K. , Hazell L. B.
Published: May 2005

The accuracy of quantified XPS/AES compositions for a given sample depends on both systematic and random errors. Parameters such as escape depths, transmission functions, sensitivity factors and whether the model of the surface physical structure used in the quantification procedure is appropriate contribute systematic errors to the quantification. Random errors arise from the Poisson statistics of electron detection. However, in many applications of practical interest, where comparison between samples is the preferred approach to problem solving, precision is more important than accuracy. In such cases, the systematic errors are very similar and the random errors arising from the Poisson statistics of electron detection dominate the problem‐solving exercise. The raw spectra should be capable of providing sufficient precision in the quantified elemental compositions so that the comparison can be made with statistical confidence. This is a particular problem where the elements of interest are present at low levels and there is concern over sample degradation.

This paper derives routines to determine the precision (arising from the Poisson counting statistics) in single intensity, peak height, peak area and quantified composition measurements for any acquired spectra, revealing some counter‐intuitive results. The beneficial effects of smoothing and background averaging are also considered. The knowledge is used to suggest novel spectral acquisition strategies to be implemented on data systems, and how they may be optimized when a result to a desired precision is required.
An Electron Spectroscopic Investigation of Attenuation Lengths of Electrons in SiO2 in the Energy Range 450 eV ≤ Ekin ≤ 3100 eV
Authors: Ebel H. , Ebel M. F. , Svagera R. , Hofmann A.
Published: May 2005

An experimental determination of the attenuation lengths of electrons in SiO2 by means of XPS and x‐ray‐excited Auger electron spectra gave a remarkable agreement with recently published inelastic mean free path data.
Determination of the distribution of molybdenum oxidation states in reduced Mo/TiO2 catalysts by factor analysis and curve fitting
Authors: Fiedor Joseph N. , Proctor Andrew , Houalla Marwan , Hercules David M.
Published: May 2005

This study shows that principal component analysis (PCA) in conjunction with iterative target transformation factor analysis (ITTFA) is able to provide an independent estimate of the number, position and, to a certain extent, the shape of spectral components required to describe the Mo 3d envelope as monitored by XPS in reduced Mo/TiO2 catalysts. Three components were required to reproduce the original data.

Abstract components from PCA were transformed through ITTFA into components which have spectroscopic meaning. ITTFA was able to predict the position and basic shape of the three spectral components and thus give an estimate of their relative contribution to each spectrum. The three spectral components were attributed to Mo6+, Mo5+ and Mo4+. These factor analysis (FA) results were used in conjunction with non‐linear least‐squares curve fitting (NLLSCF), to provide a detailed description of the Mo 3d envelope during reduction of the Mo/TiO2 catalysts.
XPS Study of hydroxylated oxide layer formation on pure iron and their acid–base properties
Authors: Kurbatov G. , Darque‐Ceretti E. , Aucouturier M.
Published: May 2005

X‐ray photoelectron spectroscopy was used to study the hydroxylated oxide layer formation on pure iron and their acid‐base properties. Eighteen samples prepared ex situ were examined. A model of hydroxylated oxide multilayer structure formation and quantification of its composition were proposed. An assumption on the formation of different hydroxyl group species was made.

X‐ray photoelectron spectroscopy analysis and ion exchange experiments at the sample surface in solution containing K+ at different values of pH were used for estimation of acid‐base properties.
Porcelain bonding on Ti: Its dependence on surface roughness, firing time and vacuum level
Authors: Hautaniemi J. A. , Juhanoja J. T. , Herø H.
Published: May 2005

Adherence of porcelain on titanium and possible bonding mechanisms were studied. The main variables were surface roughness. The bond strength for Al2O3‐blasted rough surfaces was superior to those ground by SiC paper or polished. The fracture was partly cohesive for the Al2O3‐blasted surfaces as a result of mechanical interlocking. For smoother surfaces fracture occurred adhesively. Increased firing time and reduced vacuum level decreased the bond strength when mechanical interlocking was weak. This was most likely related to poor adherence of the interfacial oxide layer to the titanium substrate.
Dimerization of polystyrene during static SIMS measurements
Authors: Licciardello Antonino , Pignataro Salvatore , Leute Angelika , Benninghoven Alfred
Published: May 2005

In this work we report on the results of some static time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) experiments performed on low‐molecular‐weight narrow distribution polystyrene. Evidence of cross‐linking during analysis is found, as indicated by the presence of peaks corresponding to molecules formed by linking of two initial polymer chains. The effect, which can be easily taken into account, does not appreciably affect the molecular weight distribution parameters obtained. However, the observed phenomenon gives the indication that, at least in the case of particularly sensitive systems, ion beam‐induced modification can occur also in static SIMS experiments. In addition, the observed phenomenon can be of relevance in modelling the sputtering of large molecules.
Depth profiling with sample rotation: Capabilities and limitations
Authors: Hofmann S. , Zalar A.
Published: May 2005

Depth profiling with sample rotation has become a frequently applied method to obtain the in‐depth distribution of composition in thin films with high resolution. Sample rotation strongly diminishes the effect of local variations of the ion beam intensity and of the sputtering yield, which are the main cause of increasing surface roughness during sputtering and therefore of profile broadening. Capabilities and limitations of rotational profiling are considered with respect to its dependence on various parameters, such as inhomogeneity of the ion beam instensity, ion incidence angle and rotation speed. In particular, it is shown that non‐linear components and excentric movement of the sample lead to periodic features in the profile and to non‐vanishing degradation of depth resolution with depth. For smooth sample surfaces, depth resolution improves with increasing ion incidence angle but is much less pronounced, as for profiling with stationary samples. For originally rough surfaces, the deterioration of depth resolution with increasing ion incidence angle is considerably reduced. The key parameter for optimized conditions in rotational profiling is the ratio of sputtering rate and rotation speed. The minimum necessary, useful rotation speed depends on this ratio and on the magnitude of other contributions to the depth resolution that are not affected by sample rotation.
Electrochemical, ellipsometrical and surface analytical investigations of passive layers on binary Fe/Al alloys
Authors: Schaepers Dirk , Strehblow Hans‐Henning , Künzelmann Ulrich , Schwarz Yvonne
Published: May 2005

X‐ray photoelectron spectroscopy, ISS, ellipsometry, electrochemical impedance spectroscopy and electrochemical methods have been used to investigate the passive layers (PAL) on iron/aluminium alloys with low contents of Al (2 up to 12 wt.%). Ellipsometric measurements were performed during the galvanostatic reduction of PAL formed on Fe/8Al in 0.5 M Na2SO4/H2SO4 (pH 3.85) at various potentials. Combining the results of ellipsometric singlelayer model evaluations and of the electrochemical reduction curves it was found that the outer part of the PAL mainly consists of the relatively stable γ‐Fe2O3. Its fraction to the overall thickness of the PAL gives a maximum value when the alloy is passivated at +1 VSHE. At higher potentials, porous films with both decreasing capacities and polarization resistances, measured by impedance spectroscopy, are formed. The XPS and ISS sputter depth profiles of PAL on Fe4/12Al formed in phthalate buffer (pH 5) at +1 VSHE showed an Al enrichment in the centre of the layers. The reductive dissolution of the passive layer in close combination with XPS analysis at distinct states of this process yields similar depth profiles. These results suggest the formation of mixed Fe/Al oxides or oxide compounds.
Development and practical application of a transmission x‐ray photoelectron spectrometer
Authors: Jenkins S. N. , Castle J. E.
Published: May 2005

There is an increasing demand to obtain XPS analyses from smaller sample areas. The development of a transmission x‐ray photoelectron spectrometer will allow spectrum acquisition and imaging with a lateral resolution of approaching 1 μm2. The principle is based on back‐foil excitation where thin samples were placed on an aluminium foil. Electron irradiation of the foil produced x‐rays locally and this, in turn, gave rise to a small source of photoelectrons from the opposite side of the sample. Rastering the electron beam scanned the x‐ray interaction volume, which allowed imaging. Photoelectron lateral resolution was dependent on the sample and foil thicknesses and was determined by the x‐ray excitation volume.

In this work a VG Scientific MA500 was modified to give the ideal 180° geometry for transmission x‐ray photoelectron spectroscopy (TXPS). A hemispherical analyser with an extended high‐magnification transfer lens ensured a large solid angle of photoelectron collection and the hemispherical analyser gave the, previously unobtainable, energy resolution necessary to obtain chemical state information. Certain aspects unique to TXPS and image interpretation are described, following discussions of spectral interpretation in the previous paper.

It is believed that the local production of x‐rays by a scanning electron beam is the ideal way to examine the ultramicrotomed sections through interfaces and soft composite materials. Harder materials, such as ceramics and metals, require ion beam thinning in a similar way to transmission electron microscopy specimens. A magnesium–aluminium alloy is ion beam thinned to demonstrate TXPS from a harder material. The interlayer between a chlorine‐containing latex and mild steel is also analysed by TXPS following the removal of the bulk substrate and ultramicrotomy. This illustrated the applications in adhesion science, sample stability under analysis and localization of point analyses.
ToF SIMS study of the desorption of emulsifiers from polystyrene latexes
Authors: Weng L. T. , Bertrand P. , Stone‐Masui J. H. , Stone W. E. E.
Published: May 2005

The desorption of emulsifiers from the particle surface of polystyrene latexes prepared by emulsion polymerization has been studied by Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF SIMS). Two polystyrene latexes prepared with respectively sodium dodecyl sulphate and sodium dodecylbenzene sulphonate as emulsifiers were compared. It has been shown that the quasi‐molecular, parent ions and the characteristic fragments of the emulsifiers can easily be observed in positive and negative ToF SIMS. But these ions are more sensitive in the negative mode. The results have shown that after extensive purification with mixed‐bed ion‐exchange resins, the emulsifier was totally absent on the latex prepared with sodium dodecyl sulphate and that only traces of the emulsifier exist on the latex prepared with sodium dodecylbenzene sulphonate. These results suggest that strong acid emulsifiers can be desorbed by mixed‐bed ion‐exchange resins.
Surface chemical changes in PVD TiN layers induced by ion bombardment
Authors: Bertóti I. , Mohai M. , Sullivan J. L. , Saied S. O.
Published: May 2005

TiN layers produced by the PVD method were subjected to bombardment by different ion species applied in sequence. The relative atomic concentration and the chemical states of the elements in the surface layer were determined by means of x‐ray photoelectron spectroscopy. The composition and chemical states of a reference sample after wet chemical etching were taken to be representative for the stoichiometric TiN not affected by ion sputtering. For this sample characteristic line energies of Ti 2p3/2 = 454.7 eV and N 1s = 396.7 eV were found. Alternate bombardment with Ar+, N2O+ ions (1–5 keV) results in significant compositional and chemical state changes. Ar+ bombardment leads to preferential loss of N from the outermost (1–3 nm) surface layers of the nearly stoichiometric TiNx (x = 1.0–1.1) without observable changes in the chemical state of the constituents. Bombardment with N2+ ions leads to a build‐up of excess N (x ≫ 1) followed by the appearance of new N 1s and Ti 2p lines at 395.8 ± 0.3 eV and at 456.3 ± 0.3 eV, respectively. N2O+ bombardment increases the O and decreases the N concentration together with a concomitant shot out of a Ti 2p3/2 component peak at about 457.6 eV assignable to Ti2O3.
New spectrometric method for determination of sputtering parameters in glow discharge plasmas—use of helium matrix plasma gas
Authors: Wagatsuma Kazuaki , Hirokawa Kichinosuke
Published: May 2005

In Grimm‐type glow discharge spectrometry, a simple experimental method employing a helium–matrix plasma gas containing several per cent argon is developed to estimate the sputtering yield ratio of the constituents in single‐phase binary alloys. Whereas the voltage–current characteristics of the pure argon plasma strongly depend upon the kind of cathode material, those of the plasma using the mixture gas are almost the same, independent of the alloy composition of the samples. Emission spectra from this plasma source can be excited under similar excitation conditions and thus the observed emission intensities are determined principally by the number of sputtered atoms entering the plasma. The sputtering yield ratios in copper–nickel and nickel–cobalt binary alloys are estimated from analysing variations in the emission intensities with the alloy compositions. The yield ratios obtained correspond well with the values reported in previous works.
The new perspectives in surface and interface analysis
Authors: Margaritondo G.
Published: May 2005

We briefly review the advances in two new domains of surface and interface science: spectromicroscopy and free electron laser spectroscopy, with particular emphasis on the programs of our Centre de Spectromicroscopie of the Ecole Polytechnique Fédérale in Lausanne and of its partners.
Hydrogen content of C60 fullerenes, measured by elastic recoil detection
Authors: Brandstötter A. , Benka O. , Palmetshofer L. , Steinbauer E. , Kastner J.
Published: May 2005

The hydrogen content of thin films of C60 fullerenes, measured by elastic recoil detection (ERD), is investigated. In ERD analysis a new method for particle identification is employed using the ion‐induced electron emission from thin carbon foils. Since the electron emission yield depends on the nuclear charge of the penetrating particle, recoiled H ions and scattered He projectiles can be separated. The reliability and the sensitivity of the technique were checked by analysing a series of ion‐implanted H profiles in silicon. The sensitivity is better than 0.1 at.% H. In as‐grown fullerene films a hydrogen content of about 3 at.% has been found throughout the film. After doping of the fullerene films by ion implantation of K the hydrogen content increased up to 6 at.% in the implanted region.
The influence of Al oxidation on the Cu/Al2O3 interface formation: An XPS study
Authors: Ciampi S. , Di Castro V.
Published: May 2005

The formation of Cu/Al2O3 interfaces at room temperature on aluminium polycristalline samples oxidized in different ways has been studied by XPS. We have compared the growth of copper on samples oxidized by O2, H2O and air respectively. In all the analysed systems an initial oxidation of copper to Cu(I) and a good dispersion of the deposited metal is observed, followed by copper clusters formation. The sample oxidized in air shows a better dispersion of the metal and needs a larger amount of copper to reach the bulk copper spectra.
Optical second harmonic generation as a crystalline surface symmetry probe for III–V semiconductors
Authors: Kravetsky I. V. , Kulyuk L. L.
Published: May 2005

A simple way of calculating the second harmonic (SH) rotational anisotropy (the dependence of SH intensity on the sample rotation angle about its surface normal) for arbitrary oriented surfaces of the 43m crystals (e.g. III–V semiconductors) is described. Second harmonic generation (SHG) reflected from (001), (111), (110) and vicinal (001) surfaces of InP and GaAs single crystals was experimentally studied. It is shown that surface crystallographic orientation of the reflecting surfaces leads to a very pronounced effect on the rotational anisotropy and intensity of the SHG from these surfaces. A good agreement between calculated and experimental SH dependences is observed.
Internal analyser inelastic scattering effects in XPS quantitative analysis
Authors: Battistoni C. , Mattogno G. , Righini G.
Published: May 2005

The shape of spectrum in XPS depends on processes in the sample and on the properties of measurements systems. Noise, electron energy analyser resolution, electron inelastic scattering in the sample and analyser, and non‐monochromatic radiation produce a quality reduction of spectrum for quantitative analysis. The undesired scattering of electrons on the outer hemisphere of the analyser or into the lens system leads to spectral background shape distortion and difficulties in the analysis of intensity transmission and resolution functions. A new mathematic procedure, based on deconvolution method, for evaluation and removing instrumental artefact is proposed.
Preparation and characterization of cubic boron nitride and metal boron nitride films*
Authors: Gissler W.
Published: May 2005

Boron nitride has generated much scientific interest due to the outstanding material properties of its cubic modification (c‐BN) which can be compared with those of diamond, and to its metal (M) boron nitride compounds (MBN) which have extraordinary mechanical properties such as high hardness and high elasticity. This paper compares and discusses both of these thin film materials, concentrating in particular on their preparation and their mechanical properties in view of future applications as wear‐resistant coatings.

There is a strong indication that the mechanism of c‐BN film formation by commonly used physical vapour deposition (PVD) methods is based on recoil implantation of surface atoms into deeper layers. This process creates considerable compressive stress compromising the production of technologically valuable coatings of c‐BN composition. On the other hand BN‐based transition metal films can be made as hard as or even harder than c‐BN films if suitable preparation methods are applied which promote nanometric grain sizes and a mixed phase composition. This paper discusses: (1) Ti implantation into hexagonal BN layers; and (2) co‐sputter deposition from a Ti and Hf target, respectively, and from a BN target; and (3) Ti/BN multilayer interdiffusion. MBN films show good adhesion to metallic substrates such as HSS steels, and preliminary wear tests with a pin‐on‐disk tribometer indicate promising characteristics.

Bonding and chemical composition of the films were investigated by electron spectroscopy for chemical analysis (ESCA)‐Auger spectroscopy, the structure and crystallite size by glancing angle x‐ray diffractometry, and the hardness and elasticity by the nanoindentation technique.
Replacement of heavy metal containing pigments in PVC
Authors: Graff John , Osmer Dennis
Published: May 2005

Many companies are facing the challenge of replacing heavy metal containing pigments in their products because of possible legal restrictions as well as toxicological and environmental considerations. Replacing one pigment in a single formulation is not generally an insurmountable problem, but replacing this pigment in hundreds or perhaps thousands of formulations might generate some anxiety. The purpose of this paper is to review some of the techniques useful for pigment selection. Colorimetric properties and physical characteristics form the basis for logical selection. Chromaticity characteristics, data on relative opacity, migration resistance, hat and light stability of more than thirty pigments will be included. Examples of the use of the techniques illustrating the replacement of chromate pigments in five colors will be presented. Comparative performance data will be included. On the basis of the information presented, limitations in making high chroma yellow will be discussed.
Polymer reprocessing: Properties of polyethylene—polyvinyl chloride mixtures
Authors: Bataille P. , Jolicoeur C. , Schreiber H. P.
Published: May 2005

The increasing tendency to consider waste polymers as suitable stocks for reconversion calls for guidelines as to the processing and end‐product behavior of mixtures involving commodity polymers. In the present case, flow and some mechanical properties of mixtures involving low density polyethylene (PE) and filled polyvinyl chloride (PVC) were determined and used as a base‐line of comparison with similar properties of multi‐component mixtures involving potential compatibilizers for the incompatible matrix pair. Chlorinated polyethylene (CPE) ethylene‐vinyl acetate (EVA) copolymer and ELvaloy polymeric plasticizer were the property modifiers selected. Blends were produced by roll‐mill, Brabender or Banbury mixing. Flow properties were measured by capillary viscometry and solid‐state properties were characterized by stress‐strain data and tensile impact performance. Melt viscosities were non‐linear functions of blend composition and varied significantly with the choice of compatibiliser, EVA and CPE producing greater benefits of melt strength than did Elvaloy. Elastic moduli, ultimate tensiles and tensile impact data also responded to the presence of compatibiliser, the EVA and CPE again being more effective in upgrading the properties of the incompatible matrix pair than was Elvaloy. Results, while preliminary, suggest guidelines for the composition of PE/PVC stocks with upgraded performance balance.
The effect of blending resins on plastisol performance
Authors: Bannish M. K. , Renshaw J. T.
Published: May 2005

Blending resins are well known by plastisol compounders as an economical substitute for PVC dispersion resin and as viscosity modifier. As dispersion resin supply tightens, interest grows in blending resins and how to choose the one that best fits the compounder's specifications. Eleven representative blending resins have been characterized, compounded into plastisols and screened for performance. A regression analysis and resulting contour plots have supplied a means of correlating resin molecular weight, particle size and surface area with plastisol, gel/fusion, and physical properties. The trends described in the contour plots allow the prediction of the best blending resin criteria for a specific application.
Control of chemical embossing technology
Authors: Klásek Antonían , Janǐs Rahula , Šimoníková Jarmila , Šimoník Josef
Published: May 2005

To achieve highly decorative, textured finishes on blown PVC wall covering and flooring products, blowing agent inhibitors are printed on pre‐blown sheeting. By inhibiting blow in the printed area, simulated leather and geometric patterns can be developed. Such products have wide consumer appeal. This study presents methodology for determining the efficiency of a series of proposed inhibitors. The most pronounced inhibitive effects on the blow of azodicarbonamide (AZDA) come from the use of phenolic compounds and polyamines. Careful selection of carrier solvents will control inadvertent diffusion transport of the inhibitor towards AZDA particles. An anomalous catalytic effect of maleic anhydride was observed in this study.
The effect of antimony oxide flame retardants on color of vinyl films
Authors: Abrams Richard L.
Published: May 2005

The scattering power, or whiteness of antimony oxide varies directly with particle size. In extremely small particle sizes, when scattering power is low, the film is quite transparent. As particle size increases, scattering power increases to a maximum, somewhere between 0.2 and 1.0 micrometer, drops off again with increasing particle size. In white and pastel film, a high‐scattering grade will supplement the major pigment. In dark and deep colors, use of a more transparent grade, even one at a premium price, may prove more economical, since pigment loading may be reduced.
Injection molding PVC
Authors: Shaw Lane G.
Published: May 2005

Injection molding rigid PVC is no longer the chore it once was. Advances in resin properties, additive systems, and molding equipment have allowed injection molders to take advantage of PVC's favorable economic, weatherability, flame retardant, and chemical resistant properties. As a result, injection molding of PVC is entering a new era. With the proper equipment and formulations, today's PVC molder is graduating from pipe fittings to ever more profitable, yet demanding, parts and applications.
A quick method for determining the acid gas evolution from PVC formulations
Authors: Smith Gregory F.
Published: May 2005

A method has been developed for the determination of the amount of acid gas produced during the thermal decomposition of PVC formulations. A method was required to support a program to reduce acid gas generation by retention of hydrogen chloride in the char phase. The traditional method (a modified Schoeniger) produces inaccurate and irreproducible results due to uncontrolled combustion. Other methods often take an excessive amount of time to run and may need expensive and unusual equipment. The test described here is accurate, fast, reliable, reproducible, and requires equipment which is readily available in a typical chemical laboratory. The method is based on the modified Schoniger test, but the sample is thermally decomposed by the action of a small coil of electrical resistance wire. The sample is held in a porcelain boat inside the heating coil. The thermal decomposition of the compound can thus be carefully controlled. The present paper describes studies of the effect of sample size and coil power on acid gas generation. It also presents results of other tests, for comparison purposes.
PVC and incineration
Authors: Carroll William F.
Published: May 2005

Among the most feared toxic chemicals known to man is 2,3,7,8‐tetrachlorodibenzodioxin (TCDD). PVC is a source of chlorine in waste and therefore it has been contended that its means of disposal should not be incineration. It is argued that the chlorine content of non‐PVC sources is in excess of that needed for dioxin production and therefore exclusion of PVC from municipal waste will have little effect upon harmful emissions. This investigation presents evidence substantiating this concept.
Alumina trihydrate in flexible PVC—effects of alumina particle morphology
Authors: Green D. W. , Dallavia A. J.
Published: May 2005

Recent increased use of ultrafine mechanically ground alumina trehydrate (ATH) as a flame retardant and smoke suppressant has occurred. This growth has, to some extent, displaced the traditional fine precipitated forms of ATH in a variety of polymer applications. In general, the morphology of the more expensive precipitated ATH is different from ground ATH. In this study there appears to be little effect of ATH particle morphology on the PVC performance properties tested.
Polymeric plasticizers for PVC
Authors: Prud'Homme R. E.
Published: May 2005

High molecular weight plasticizers can be used if they have a low Tg and are miscible with PVC. For example, linear polyesters exhibit miscibility with PVC when their [CH2]/[COO] ratio is intermediate; in that range, as “miscibility window” has been found. However, the degree of miscibility of miscible polymer blends vary with the structure of the polymers involved and thier concentration. The miscibility of these systems is often assessed by the measurement of a single Tg as a function of composition. A careful examination of experimental data of polyester/chlorinated polymer blends, as well as the use of the free volume theory, indicates that several of these systems exhibit a cusp as a function of composition, which is characterized by a critical volume fraction and a critical temperature. Specific examples are given.
The Use of the ultimate elastic wall stress (UEWS) in evaluating PVC polymer blends
Authors: Schwencke H. F.
Published: May 2005

The UEWS test is described as a sensitive means to measure the stress in a material at which the first inelastic behavior becomes apparent. Particularly interesting observations have been made with PVC, where the aging of the material can be shown in a master curve diagram giving the relation between the UEWS and the age of the material at different molecular weights. Using this test as a tool, the performance of blends can also be measured. Blends of PVCs with different molecular weights and blends with various polystyrenes, polyvinyl acetate, and CPE are discussed.
Titanium dioxide, extenders, fillers, not‐in‐kind replacements—what does it mean for plastics?
Authors: Holtzen D. A.
Published: May 2005

Recent publication and presentations extol the virtues of filler pigments as titanium dioxide extenders. Theory predicts and experiment shows that in plastic systems, where pigment concentrations are relatively low, compared to paints and inks, fillers do not significantly improve the optical efficiency of titanium dioxide. Close examination of published data shows that there are many unanswered questions such as: How do variations in compounding conditions affect efficiency? Has sufficient attention been paid to measurement of light reflectance and transmission? Have the effects of light scattering and absorption been taken into account to explain optical measurements? What we have found is that there is no easy “fix” to improve the efficiency of titanium dioxide by the use of filler pigments. Serious questions also remain unanswered regarding the effect of ad hoc replacement of TiO2 with filler in systems requiring light stability such as rigid polyvinyl building products.