bluuebunny/crossref_metadata_2025 huggingface dataset:
A fracture technique for Auger analysis of a zinc/steel interface
Authors: Eberle W. J.
Published: December 2004

A low‐temperature fracture technique was used to expose an extremely thin aluminium interface located between a very thick hot‐dip galvanized coating and a steel substrate. The representative sample was saw‐cut through the steel substrate just short of the hot‐dip galvanized interface, immersed in liquid nitrogen and fractured. The exposed aluminum‐rich boundary layer was analyzed by scanning Auger microscopy (SAM) to determine the effects of the galvanizing process on the boundary layer development.
Identifying type 304 stainless steel flange defects using scanning Auger microscopy (SAM)
Authors: Eberle W. J. , Clough S. P.
Published: December 2004

An unusual number of large stringer defects were found in cross‐forged type 304 austenitic stainless steel ultrahigh vacuum (UHV) flanges. These defects are cosmetically displeasing, they can affect the material's machinability and they can also affect the vacuum integrity of a UHV system. In this study, scanning Auger microscopy was used to identify accurately the defects as ferritic inclusions. This information was used to justify a change in forging and heat‐treating procedures, resulting in the reduction of large ferrite segregants and creating a more homogeneous microstructure. Subsequently, the rejection rate was reduced more than 50‐fold.
Chemical shifts in the MNN Auger spectra of Cd, In, Sn, Sb and Te
Authors: Lynn L. C. , Opila R. L.
Published: December 2004

The MNN Auger spectra of a series of elements, Cd through Te, have been examined as a function of chemical state. The spectra of Cd, In, Sn and Sb do not change shape significantly whether the element is present as a metal, semiconductor or insulator, e.g. Cd, CdTe or CdO. The Kinetic energies of the Auger electrons do shift by large, easily measurable, amounts of 3–6 eV. These shifts are to lower kinetic energy with respect to the pure metal and are largest for the oxides and least for the semiconductors. These spectra are atom‐like and the two final‐state holes are localized on one atom. The shape of the MNN Auger spectrum of Te reflects changes in its chemical state and shows shifts in energy similar to those seen for Cd, In, Sn and Sb. The changes in energy are much larger than those seen in photoemission and are the result of changes in the extra‐atomic screening of the double‐charged final‐state ion.
AES: Energy calibration of electron spectrometers. II—results of a BCRinterlaboratory comparison co‐sponsored by the vamas SCS TWP
Authors: Seah M. P. , Smith G. C.
Published: December 2004

An interlaboratory assessment of the kinetic energy measurement of Auger electron peaks has been conducted using reference foils of copper, silver and gold. The results, involving data from spectrometers manufactured by seven companies, were received from 39 laboratories. The standard deviations of the data in both the direct and differentiated spectra were ∼60% of the values found in the ASTM‐sponsored round robin in 1982, indicating only marginal improvements in spectrometer calibration since that time. By comparing the copper M2,3VV and L3VV measurements from the sets of returned data with the reference values from Part I, the energy scale and energy zero errors were calibrated for each instrument. Using these values and the relativistic term for the particular spectrometer, corrections to the respondees' values for the Ag M4NN, Au N6,7VV and Au M5N6,7N6,7 peak energies could be determined. The scatters of these calibration‐corrected values were very low, amounting to ∼15% of the values in the ASTM round robin for all of the spectrometers tested, but reducing to only 6% for the high‐resolution spectrometers. For both the direct and differential modes the calibration‐corrected Au N6,7VV and Ag M4NN average peak positions diverged by less than the 0.07 eV standard deviations of their means from the reference values given in Part I. The copper reference values given in Part I thus appear to be suitable for calibrating AES instruments to an accuracy comparable to the measurement repeatabilities of the instruments concerned and seem to be quite sufficient for their overall energy calibration.
SSIMS, XPS and microstructural studies of ac‐phosphoric acid anodic films on aluminium
Authors: Johnson D. , Vickerman J. C. , West R. H. , Treverton J. A. , Ball J.
Published: December 2004

ac‐Phosphoric acid anodizing of aluminium results in the initial formation of a featureless barrier film on the metal surface, followed by nucleation and growth of a filament structure. The rate of filament growth and filament diameter are dependent upon the anodizing temperature. Static secondary ion mass spectrometry (SSIMS) and XPS indicate that organic contamination levels on all anodized surfaces are low regardless of anodizing temperature and that contaminant levels tend to decrease as anodizing proceeds. Apart from the very intense Al+ in the positive ion spectra and the O− and OH− peaks in the negative ion spectra, SSIMS spectra were characterized by the appearance of a series of peaks from AlxOyHz fragments. Appearance of AlO+ or AlOH+ clusters in the positive ion spectra depended on the anodizing conditions. Both XPS and SSIMS confirm the presence of phosphates on the anodized surfaces but differences in results from the two types of analyses imply that unknown factors affect the concentration present.

Low contaminant levels, corrosion inhibition from surface phosphates and the filamented topography developed will all affect the adhesive properties of the surface.
Improved depth resolution in Auger depth profiles of TiN thin films by optimized sputtering parameters
Authors: Pamler W. , Wildenauer E. , Mitwalsky A.
Published: December 2004

The depth resolution in Auger in‐depth profiles of TiN thin films on smooth Si substrates is determined by the evolution of a sputter‐induced surface roughness. It is shown that this effect depends critically on the ion angle of incidence. Therefore, the depth resolution can be improved most efficiently by optimizing the bombardment angle. The ideal sputter angle for Ar+ ions is found to be ∼76° and for Xe+ ions >80° to the surface normal, although slightly less grazing angles of incidence are preferred for more practical sputter rates. For any angle, the depth resolution can be improved further by reducing the ion energy and using Xe+ instead of Ar+ ions for etching. Thus, for TiN thicknesses of 83 nm and 650 nm, the sputter‐induced interface broadening can be as low as 3.5 nm and 8 nm, respectively.
XPS determination of oxygen‐containing functional groups on carbon‐fibre surfaces and the cleaning of these surfaces
Authors: Desimoni E. , Casella G. I. , Morone A. , Salvi A. M.
Published: December 2004

Careful curve fitting is needed when using XPS to investigate oxidized functional groups on carbon‐fibre surfaces. This is important because the core regions often contain a number of overlapping features some of which are of low intensity, and the C 1s region is influenced by an asymmetric graphitic feature. The fitting approach used requires that the same content of oxygenated species must be obtained from both the C 1s and O 1s regions. The approach is used to analyse untreated fibres before and after cleaning.
Quatitative AES: Reducing errors in measured analogue spectral intensities through control of the electron detector
Authors: Seah M. P. , Smith G. C.
Published: December 2004

AES spectra, when measured in the constant ΔE/E mode, may be distorted by the varying efficiency of the electron detector, usually a channel electron multiplier (CEM). In the analogue mode, this is a problem that increases as the emitted electron energy falls below 200 eV. Instruments may be modified by adding transparent meshes and by biasing the front of the CEM by 200 eV. In this way, the spectral distortion may be reduced by a factor of 10 at 50 eV, so that the resultant spectral shape is within ±10% of the true shape over the energy range 25–2000 eV. This small distortion may be calibrated accurately so that true spectra may be derived from all modified instruments with greater reliability and confidence than in unmodified instruments.
Thermal stability of benzotriazole on copper during atmospheric corrosion
Authors: Christensen T. M. , Sorensen N. R.
Published: December 2004

Atmospheric corrosion of copper can result in substantial problems for electrical interconnection in microelectronic applications. We have used x‐ray photoelectron spectroscopy (XPS) to examine the effects of benzotriazole (BTA), an organic corrosion inhibitor, on atmospheric oxidation and sulfidation of polycrystalline copper in the temperature range 30‐200 °C. XPS results demonstrated that BTA was lost depended on the ambient composition. BTA was least stable in sulfur‐containing environments, disappearing from the surface at temperatures above 150 °C. BTA was quite stable in pure nitrogen and in a vacuum up to temperatures near 200 °C. This suggests that the loss mechanism involved a chemical reaction rather than solely a thermal process. The BTA‐Cu(II) complex existing at room temperature was irreversibly converted into a BTA‐Cr(I) complex upon heating above 90 °C in a vacuum.
XPS peak shapes accounting for the inelastic scattering of photoelectrons
Authors: Végh János
Published: December 2004

A simple and fast method to account for inelastic scattering of photoelectrons is presented. A new peak shape class is introduced, which consists of a conventional photopeak and a tail originating from the inelastic scattering of the electrons, created originally in the photopeak. The proposed peak shapes with inelastic tail can be described using up to three additional parameters. The method has both practical and computational advantages.
Characterization of MoSi2 coatings obtained by atmospheric pressure and low‐pressure plasma spraying
Authors: Zacchetti N. , Mizuno K.
Published: December 2004

The high‐temperature oxidation resistance property of MoSi2 coatings is strongly influenced by the chemical composition, density and structure of the deposit. The aim of this work is to determine the role of the deposition process in the microchemistry and microstructure of the coating. In order to achieve this task, we compare MoSi2 produced by LPPS (low‐pressure plasma spraying) and conventional APPS (atmospheric pressure plasma spraying) techniques with the aid of a complementary use of characterization methods such as SEM, EPMA (electron probe microanalysis), CMA (computer‐aided microanalysis), GDOS (glow discharge optical spectroscopy) and XPS. From the overall results it is evident that the application of plasma spraying under low pressure considerably improves MoSi2 layers. They are characterized by a higher density, with fewer pores and discontinuities, and have a more uniform chemical composition and a better coating‐substrate interface.
Oxygen‐induced surface segregation of hydrogen in polycrystalline titanium
Authors: Azoulay A. , Atzmony U. , Mintz M. H. , Shamir N.
Published: December 2004

Oxygen‐induced surface segregation of hydrogen has been investigated in polycrystalline titanium. It was found that sulphur impurities in titanium preferentially segregate to the surface on heating the sample. Consequently, the properties and reactivity of the sulphur‐containing surfaces were modified relative to sulphur‐free samples in a way which enabled the performance of quantitative kinetic segregation measurements utilizing direct recoil spectrometry (DRS). The time behaviour of hydrogen accumulation on the surface pointed to a segregation mechanism involving subsurface‐to‐surface hopping as the rate‐determining step.
Some practical applications of elastic peak electron spectroscopy
Authors: Jardin C. , Gergely G. , Gruzza B.
Published: December 2004

Practical applications of elastic peak electron spectroscopy (EPES) are presented to demonstrate the advantages of this technique in the study of materials subjected to electron beam degradation and surfaces involving hydrogen species. Beam damage on phthalocyanine layers is detected at low beam power (Ep = 500 eV, Jp = 10−3 A cm−2, grazing incidence angle 20°) with a cross‐section of about 8 × 10−18 cm2, as deduced from EPES experiments. The change in the emission yield of elastically reflected electrons during electron irradiation of this ’fragile‘ molecular material is related to an increase in the mean atomic number due to breaking of CH bonds and to desorption of hydrogen. Using very low current density to prevent primary beam effects, the distinction between different metal phthalocyanine layers (PcZn and Pc2Lu) and the study of diffusion induced by heat treatments are possible by EPES, in contrast to AES and EELS (electron energy loss spectroscopy) techniques. Application of EPES to the analysis of titanium alloy TA6V submitted to a hydrolysis treatment in hot water is also reported. The enhancement in elastic scattering with decreasing primary energy suggest that hydrogen is present at the surface of the hydrolysed sample.
Characterization of graphite‐supported platinum catalysts by electrochemical methods and XPS
Authors: De Bruijn F. A. , Marin G. B. , Niemantsverdriet J. W. , Visscher W. H. M. , Van Veen J. A. R.
Published: December 2004

X‐ray photoelectron spectroscopy and cyclic voltammetry have been used to characterize 4.9 wt.% platinum‐on‐graphite catalysts used for the oxidation with molecular oxygen of methyl α‐D‐glucoside in aqueous solution. Cyclic voltammetry indicates that a surface oxidic layer is formed on the platinum particles upon exposure to ambient air. This oxidation could not be confirmed by XPS, however. The oxidation of methyl α‐D‐glucoside in the liquid phase is accompanied by growth of the platinum particles. Open‐circuit potential measurements indicated an increasing oxygen coverage of the platinum surface during reaction.
Characterization study of polycrystalline tin oxide surfaces before and after reduction in CO
Authors: Drawdy Jean E. , Hoflund Gar B. , Davidson Mark R. , Upchurch Billy T. , Schryer David R.
Published: December 2004

Polycrystalline tin oxide surfaces have been examined before and after reduction in 40 Torr of CO at 100 and 175°C using Auger electron spectroscopy (AES), electron spectroscopy for chemical analysis (ESCA), ion‐scattering spectroscopy (ISS) and electron‐stimulated desorption (ESD). The changes in the surface composition and chemical states of the surface species generally are subtle for the reductive conditions used. Some of the SnO2 is reduced to SnO and significant changes do occur with regard to the amounts and chemical forms of the hydrogen‐containing species remaining after both the 100 and 175°C reductions.
The improved MTCIP‐1A (modern thermodynamic calculation of interface properties—first approximation) and its application to the (Pt)Ni surfaces
Authors: Mezey L. Z. , Hofer W.
Published: December 2004

The MTCIP (modern thermodynamic calculation of interface properties) theory states the general condition of the thermodynamic equilibrium state (TES) for any kind of interface, any number of components and interface sublayers. In the MTCIP‐1A (first approximation) for a binary dilute solid mixture, the monolayer surface composition is calculated in the TES (allowing for a chemisorbed or segregated overlayer as well). This approach has been used successfully so far for bimetallic alloys and as well for the segregation of non‐metallic solutes on metal surfaces, and is further developed here. This new version is used for problematic PtNi surfaces, both low‐index and polycrystalline. All the parameters needed to follow the calculations are given. In all cases, the theory agrees with the experiments at last qualitatively, and in most cases even quantitatively, although the PtNi surfaces were the most problematic for theoretical calculations.
Thickness determination of surface oxides on metal powder by AES depth profiling
Authors: Norell M. , Nyborg L. , Tunberg T. , Olefjord I.
Published: December 2004

A method for thickness determination of overlayers on irregularly shaped samples is established using AES depth profiling and stereophotogrammetry. The analysis is performed on a small selected area assumed to be flat. The angle of ion incidence on the area, given by the scalar product of the ion beam vector and the normal to the surface, is obtained by determining the normal using a sterological method based on rotation of a titled sample. The variation in etch rate with the angle of ion incidence is determined for various oxides on flat samples. Application studies show that the angle of ion incidence on gas‐atomized metal particles can be determined from their spherical shape; the variation in etch rate is found to agree well with that calibrated on flat surfaces. It is also demonstrated how the presented method can be used when determining the oxide thickness in different areas on highly irregular water‐atomized metal particles.
Evaluation of take‐off‐angle‐dependent XPS for determining the thickness of passivation layers on aluminium and silicon
Authors: Gunter P. L. J. , De Jong A. M. , Niemantsverdriet J. W. , Rheiter H. J. H.
Published: December 2004

Investigating the effect of a cleaner (used to remove lubrication oil residues) on the surface composition of rolled aluminium foils, we applied angle‐dependent XPS to determine the thickness of the passivation layer on these foils. We found the simple uniform overlayer model, which has frequently been applied to translate XPS intensity ratios into a value for the overlayer thickness, to be inapplicable on these aluminium foils. However, data obtained from an Si(100) single‐crystal surface were in rather good agreement with the model. SEM images from the aluminium foils show that their surface is rough on the (sub)micron scale. We believe this roughness to be the reason for the inapplicability of the uniform overlayer model. Simulations of XPS intensity ratios for model rough surfaces support this point of view. Both experiment and simulations make it clear that one should not base XPS thickness determinations on one measurement only, because in that case the applicability of the uniform overlayer model cannot be checked.
Ultrafast electron dynamics at semiconductor surfaces and interfaces studied with subpicosecond laser photoemission
Authors: Haight R. , Baeumler M. , Silberman J. A. , Kirchner P. D.
Published: December 2004

The technique of subpicosecond angle‐resolved laser photoemission spectroscopy is described. Investigations of the dynamics of electrons excited into normally unoccupied states at the cleaved GaAs (110) 1 × 1 and Ge (111) 2 × 1 surfaces are detailed. In addition, we discuss experiments carried out on heterostructures formed by the growth of Ge on the cleaved GaAs (110) surface as well as the molecular beam epitaxy (MBE) surface of GaAs (100) and (111).
Al‐Cu‐Si/TiW interface reaction due to thermal treatments
Authors: Misawa Y. , Koike Y.
Published: December 2004

The Al‐0.5 wt.% Cu‐1 wt.% Si/TiW interface reaction due to thermal treatments in nitrogen was investigated using SIMS, x‐ray diffraction (XRD), TEM, XPS and SEM. Titanium starts to diffuse into the Al alloy layer at low temperatures such as 350°C. However, Ti has hardly any effect on the sheet resistance. Tungsten diffuses and reacts with Al above 450°C. The rugged interfacial reaction product formed after annealing at 450°C, which may be W(Al, Si)2, does not affect the sheet resistance. The needle‐shaped reaction product formed after annealing above 500°C, which is Al12 W, is responsible for the large increase in sheet resistance. An aluminium oxide layer, several nanometres thick, formed on the Al alloy surface after annealing at 500°C acts as a W diffusion barrier.
Dependence of boron axial channelling in silicon on crystal orientation
Authors: Tian C. , Gara S. , Hobler G. , Stingeder G.
Published: December 2004

The axial channelling behavior of boron implants in 〈100〉, 〈110〉 and 〈111〉 silicon wafers is investigated by secondary ion mass spectrometry. The conventional electronic stopping models are tested by comparing with experimental results. The dependence of the channelling effects on these three major low‐index directions are revealed. A three‐parameter model is presented to describe channelling of boron in silicon. The results give a deeper insight into the channelling phenomena and provide the necessary information to study an electronic energy‐loss model for boron channelling in a silicon target.
XPS studies of oxide layers on InP after oxidation in the presence of Ce4+
Authors: Debiemme‐Chouvy C. , Ballutaud D. , Sculfort J. L. , Etcheberry A.
Published: December 2004

Quantitative XPS analyses are carried out to study the III‐V semiconductor/solution interface. In the presence of ceric ions (Ce4+) solvated in sulphuric acid (H2SO4, 0.5–2 M), III‐V compounds undergo a dissolution which is completely governed by an electrochemical process. Competition between a superficial oxide growth and its quasisimultaneous dissolution determines the behaviour of the interface as a function of time. On InP some typical surface evolutions are observed, such as a decrease in the hole injection current during the reduction of cerium oxidized species. In order to explain this blocking effect, we have analysed the chemical composition of InP surfaces by XPS after oxidation in the presence of cerium ions. We report here the evolution of the oxide layer formed at the semiconductor/electrolyte interface in relation to the dipping time of the electrode and the cerium and sulphuric acid concentrations. It is observed that the lower the pH, the more soluble is the oxide layer. Moreover, increases in the cerium concentration and dipping time enhance the growth of a complex oxide layer. This layer is rich in oxidized phosphorus and strongly depleted in indium. Profiling of the layer shows a cerium distribution all over the oxide layer. The electrochemical behaviour of InP samples changes in relation to the properties of this complex multiphase film.
Weathering of wood and protection by chromium studied by XPS
Authors: De Lange P. J. , De Kreek A. K. , Van Linden A. , Coenjaarts N. J.
Published: December 2004

In order to understand better the protection mechanism of aqueous CrO3, the surface of untreated and treated wood, before and after weathering, was studied by XPS. For comparison, the reaction of CrO3 with filter paper, used as a model compound for cellulose, and with lignin powder was studied as well.

Owing to differences in the O/C ratio and the shape of the C 1s signal, cellulose and lignin can be distinguished from each other with the aid of XPS. The low O/C ratio and the high C1 (CC, CH) contribution found for the surface of wood show that the upper layer is enriched with ligin and extractives. Weathering of wood starts with the degradation of lignin, and the appearance of cellulose on the surface increases the O/C ratio and shifts the maximum of the C 1s signal to the C2 (COC, COH) position.

Aqueous CrO3 oxidizes lignin powder and possibly also cellulose. The effect on wood, as observed with XPS, is small. The protection, however, is very clear; the increase of the O/C ratio of CrO3‐treated wood during weathering is much slower than the increase for untreated wood. After weathering, the C 1s signal still resembles the C 1s signal of lignin, so the CrO3 protects the lignin from degradation.
Oxidation of Gd thin films on Si substrates via grain boundaries
Authors: Molnár G. , Petö G. , Kótai E. , Zsoldos E. , Gyulai J. , Guczi L.
Published: December 2004

The low‐temperature oxidation of Gd thin films evaporated on Si substrates and the role of Si native oxide at the interface of Gd silicide growth have been investigated by x‐ray diffraction, XPS and RBS. The Gd layer is extremely reactive towards oxygen and is quickly oxidized in air. Its reactivity can be diminished by introducing a small quantity of Si into the Gd film. In the initial stage Si is accumulated mainly at the grain boundaries of the Gd film, thereby blocking the main oxygen diffusion path and preventing Gd2O3 formation. If Si native oxide is initially present, at low temperature the growth of Gd silicide is slowed down but at high temperature Si/SiO2/Gd is easily transformed to Gd2O3.
Extended energy loss fine structure and x‐ray photoelectron spectroscopy studies of clean and oxidized Fe thin films on polycrystalline Cu
Authors: Di Nardo S. , Lozzi L. , Passacantando M. , Picozzi P. , Santucci S. , De Crescenzi M. , Den Daas H.
Published: December 2004

The electronic and structural properties of very thin iron films deposited in ultrahigh vacuum on polycrstalline copper have been studied by x‐ray photoemission and Auger spectroscopies and the extended energy loss fine structure technique beyond the L2, 3 edges of iron. Shifts in both core level and valence band binding energies together with a decrease in nearest‐neighbour distance are consistent with a cluster growth picture. Successive oxidation and thermal treatments have shown a selectivity towards oxidation of the iron deposits with respect to the copper substrate and a restoration of the cleanness of the iron deposit after thermal treatment.
Tougaard background deconvolution study of the deposition of Langmuir–Blodgett films of long‐chain hydrocarbon amines with titanyl oxalate ions
Authors: Sastry Murali
Published: December 2004

Multilayers of a titanyl oxalate complex with n‐octadecylamine were picked up onto quartz substrates by the Langmuir–Blodgett technique. X‐ray photoemission was used to detect the various species in the film and their relative concentrations. A Tougaard background deconvolution analysis of the photoelectron spectra was performed using the differential inelastic scattering cross‐section determined from reflection electron energy‐loss spectroscopy. By contrast with previous work on layer‐structured arachidate films, this analysis indicated that the various elements in the film were present with homogenous depth distributions. This is consistent with XPS take‐off angle studies and with x‐ray diffraction and electron microscopy studies, which showed the film to be amorphous. The composition of the film was determined to be TiO6.7C49N1.7, in reasonable agreement with the expected composition of TiO9C40N2.
XPS and ISS study of NiTiO3 and PbTiO3 subjected to low‐energy ion bombardment. I. Influence of the type of ion (Ar+ and O)
Authors: Leinen D. , Fernández A. , Espinós J. P. , González‐Elipe A. R.
Published: December 2004

Compositional and chemical changes in PbTiO3 and NiTiO3 induced by 3.5 keV Ar+ and O2+ ion bombardment have been studied quantitatively by XPS and ISS. Whereas in NiTiO3 the Ti/Ni ratio determined by XPS remained practically constant, a preferential loss of lead was observed in PbTiO3 during ion bombardment. In that case, Ar+ removed lead more effectively than O2+ ions. Argon ion bombardment induced strong chemical changes in both titanates: Ni2+ and Pb2+ species were nearly totally reduced to the metallic state, while Ti4+ species were partially reduced to Ti3+ and Ti2+ oxidation states. This reduction is more efficient in PbTiO3 than in NiTiO3. The preferential loss of lead in PbTiO3 and the removal at equivalent rates of Ti and Ni in NiTiO3 are discussed within the context of the chemical stability and physical constants of the compounds by assuming a chemically guided lattice relaxation of the bombarded targets. The possibility that solid‐state reactions play a role in the control of some of the results is stressed. Other possible effects, such as agglomeration or surface enrichment, are discussed by using the ISS results.
Application of the artificial neural network approach to the recognition of specific patterns in Auger electron spectroscopy
Authors: Souza M. N. , Gatts C. , Figueira M. A.
Published: December 2004

The artificial neural network (ANN) approach was applied to the identification of Auger electron spectral patterns. The ANN structure employed was the counter‐propagation architecture with an unsupervised learning algorithm. For training such a network, it is only necessary to provide a data set with samples of the patterns to be recognized, and the network itself will extract the relevant statistical information to organize similar patterns into specific classes. We used a training data set of five different Auger spectra (Fe, Au, Si, Sn, Cu) to which a random fluctuation of up to 5% of the highest peak was added. To the test set, however, the added fluctuation was up to 50% and we observed that the network was able to identify precisely and test spectrum after only a few training sessions. The ANN synapses can be interpreted as the average spectra of the training set for each specific class, tending to zero fluctuation spectra as the number of training samples becomes large. The results obtained show that even by using an extremely simple ANN structure the classification of single‐element Auger spectra was made easy also in the case of extremely noisy spectra.
X‐ray photoelectron diffraction studies of the surface chemistry of non‐stoichiometric synthetic spinel
Authors: Ash Lynne A. , Evans Stephen
Published: December 2004

Angle‐resolved XPS data from a synthetic spinel crystal of approximate composition MgO·(3.4)Al2O3 are reported and discussed. Strong x‐ray photoelectron diffraction (XPD) effects were observed both in argon ion bombarded/annealed surfaces (which were grossly magnesium‐deficient) and in chemically etched surfaces prepared by treatment with sodium peroxide at 480°C followed by an acid wash. Many major features of the XPD patterns could be explained using the enhanced forward scattering concept. The relative magnitudes of the XPD modulation of the photoelectron intensity suggest that no more than one‐third of the aluminium occupies tetrahedral sites, in accordance with magic‐angle‐spinning nuclear magnetic resonance experiments, and confirm that the magnesium, in contrast, remains predominantly in the tetrahedral sites. Thin layers of magnesium, cobalt(II) and chromium(III) oxides deposited on the crystal surface from nitrate precursors diffused rapidly into the crystal at ∼1100°C, with first‐order kinetics, but the mixed‐oxide surfaces so created showed no evidence of order.
Auger Si LVV, O KLL and N KLL lineshapes at air‐exposed silicon nitride surfaces: Pattern recognition analysis
Authors: Zemek J. , Vystrcil T. , Lesiak‐Orlowska B. , Jablonski A. , Luches A.
Published: December 2004

Auger electron spectroscopy measurements have been performed on silicon nitride layers exposed to air. The layers were deposited on Si(100) wafers kept at 300°C or 600°C by excimer laser ablation of a silicon target under various ammonia pressures. The Si LVV, O KLL and N KLL lineshapes of silicon nitride layers and of in situ prepared clean surfaces of standards are compared by applying pattern recognition (PR) methods to obtain bonding information of elements within the analysed volume. The PR results based on Auger Si LVV, O KLL and N KLL spectra compare very well. They are also in agreement with the results of XPS. The chemical states of silicon atoms in all silicon nitride layers depend strongly on the deposition conditions used. For low ammonia pressures, surface regions of silicon nitride layers show a twofold coordination with oxygen to silicon atoms (SiO2), whereas for higher ammonia pressures there is a four fold coordination of silicon to nitrogen atoms (Si3N4). The results are interpreted as follows. The silicon‐rich silicon nitride layers are formed at the lower ammonia pressure where the silicon oxide dominates over silicon nitride in the surface region, whereas for the higher ammonia pressure silicon nitride is prevalent. A new approach of the PR method, so‐called ‘cluster analysis’, shows a close similarity in the chemical states of nitrogen atoms in the nitride layer formed at higher pressure and silicon nitride standard, indicating a threefold coordination of nitrogen to silicon atoms. Subtle differences revealed in the spectral shapes elucidate the strongly correlated behavior of the N KLL lineshapes with the deposition conditions used.
Quantitative analysis of metal alloys based on the total X‐ray photoelectron spectra
Authors: Ławniczak‐Jabłońska K.
Published: December 2004

The method for quantitative XPS analysis proposed by Wertheim was used in the present work to check the composition of Ni–Mo alloys. These alloys had already been studied by the usual analysis based on the main line intensities. Both methods provided practically the same results. The sensitivity factor in these alloys is not constant, owing to changes of the crystal structure in the studied composition range. The total signal analysis offered a very quick method to estimate the alloy composition from only the wide spectrum measurement but it does not eliminate the problem of sensitivity factors, at least in the case of mixed‐phase alloys. This method is not influenced by satellites but still is sensitive to the changes of surface composition induced by sputtering.
Energy calibration of x‐ray photoelectron spectrometers: Results of an interlaboratory comparison to evaluate a proposed calibration procedure
Authors: Powell C. J.
Published: December 2004

Results are reported of an interlaboratory comparison conducted to evaluate a proposed procedure for calibration of the binding energy (BE) scales on x‐ray photoelectron spectrometers. The calibration was performed at two points on the BE scale (the Au 4f7/2 and Cu 2p3/2 lines) and checks were made of the assumption of BE‐scale linearity from measurements on other lines. It is shown here that small offsets (up to ∼0.05 eV) can arise if peaks are located with assumed backgrounds of non‐zero slope or if multipeak fits are made to Cu L3VV and Ag M4VV Auger spectra. The two parameters in the linear calibration equation could vary with analyzer pass energy and choice of x‐ray source on a particular instrument. Check measurements of the calibrations were performed with the Ag 3d5/2 photoelectron line and the Cu L3VV and Ag M4VV Auger lines; difference between the corrected positions of these lines and the corresponding reference data were satisfactorily small in most cases. For Auger lines excited by monochromatized aluminum x‐rays, however, the differences were significant and were interpreted in terms of different average x‐ray energies for the monochromated and unmonochromated x‐ray sources. The interlaboratory comparison was useful in testing the proposed calibration procedure and in providing guidance for some improvements.
Surface characterization of novel plasma‐polymerized primers for rubber‐to‐metal bonding
Authors: Tsai Y. M. , Boerio F. J. , van Ooij W. J. , Kim Dong K. , Rau Thomas
Published: December 2004

Thin (750 Å) plasma‐polymerized films of acetylene were deposited onto polished steel substrates in an inductively coupled r.f. reactor. The films were characterized by x‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectroscopy (FTIR), Auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) immediately after deposition and after aging in the atmosphere. The FTIR spectra of the as‐deposited films were characterized by bands related to mono‐ and disubstituted acetylene groups and by bands related to methyl and methylene groups. During exposure to the atmosphere, bands related to acetylenic groups decreased in intensity while new bands due to carbonyl groups appeared. When XPS spectra were obtained from films that were exposed to the atmosphere, new components assigned to oxidation products were observed in the C 1s spectra that were not observed for as‐deposited films, verifying that oxidation had occurred. Numerous peaks related to aromatic structures were observed in positive SIMS spectra of as‐deposited films. Results obtained from AES showed that the plasma‐polymerized films were continuous and that the oxide on the substrate surface was partially reduced during deposition.

Plasma‐polymerized acetylene films were excellent primers for rubber‐to‐steel bonding. Miniature lap joints were prepared by using rubber as an ‘adhesive’ to bond together pairs of polished steel adherends primed with plasma‐polymerized acetylene films. The force required to break the as‐prepared joints was ∼2000 N for a bonded area of 64 mm2 and failure was 100% cohesive in the rubber. Similar results were obtained for joints prepared using polished brass substrates.

Because of the complexity of reactions between rubber and the plasma‐polymerized primer, a model ‘rubber’ consisting of a mixture of squalene, zinc oxide, carbon black, sulfur, stearic acid, cobalt naphthenate, N,N‐dicyclohexylbenzothiazole sulfenamide and diaryl‐p‐diphenyleneamine was used to simulate the cross‐linking reaction. The results obtained using XPS, SIMS, AES and FTIR showed that sulfur diffused through the primer to form a layer of sulfide at the primer/substrate interface. Zinc and cobalt sulfides and perthiomercaptides, which formed at the interface between squalene and the plasma‐polymerized acetylene primer, catalyzed the reaction between squalene and the primer. Cross‐links between squalene and the primer were mostly mono‐sulfidic, although some evidence for di‐ and trisulfidic cross‐links was observed.
Effect of elastic scattering and cylindrical mirror analyser geometry on the evaluation of escape depths of auger electrons
Authors: Ding Z.‐J. , Shimizu R.
Published: December 2004

We have studied the effect of elastic scattering and analyser geometry on calculations of electron escape depths. A theoretical analysis of the electron escape depth has been presented that shows how it is related to the solid angle for detection and the geometrical configuration of a cylindrical mirror analyser. To estimate the extent to which elastic scattering can modify the values of the escape depth, Monte Carlo simulations of the emission of Auger electrons were carried out for Cu MVV (59 eV), Cu LMM (916 eV), Au NVV (238 eV) and Au MNN (2025 eV) signals. From the calculated depth distributions of signal electrons, we have derived a correction factor for the electron escape depth in terms of the corresponding inelastic mean free path which includes both the effects of elastic scattering and analyser geometry. We have found that elastic scattering reduces the value of the escape depth by several tens of per cent and, depending on the target, signal electron energy and analyser geometry, the ration between the escape depth and the inelastic mean free path varies from 0.4 to 0.6.
Quantitative XPS and AFM surface analysis: Study of a patched gold overlayer on graphite
Authors: Gollion Ph. , Grenet G.
Published: December 2004

A patched gold overlayer obtained by thermal evaporation on graphite was investigated by x‐ray photoelectron spectroscopy (XPS) and by atomic force microscopy (AFM). The fraction of the substrate area covered by gold and the overlayer thickness are deduced from XPS angular measurements. These results are compared with topo‐graphic data as given by AFM.
Direct morphological study of metal/polymer interfaces by scanning force microscopy
Authors: Akari Sabri , Esselink Eddy , Hadziioannou Georges
Published: December 2004

Using a scanning force microscope, direct imaging of the metal/polymer interface was achieved for the first time by removing the evaporated metal film from the deposited polymer and imaging the side that was exposed to the polymer. This technique allows direct sight of the metal/polymer interface and provides information about the possible effects related to metal deposition on polymers. For comparison, two different metals, gold and aluminium, with fairly different physical properties were evaporated on a spin‐coated poly‐3‐octylthiophene polymer. While the gold film exhibits fine granulates forming a semi‐homogeneous film, the aluminium film shows large elongated protrusions forming a network structure.
Measuring the bulk flow properties of PVC resins
Authors: Schwaegerle Paul R.
Published: December 2004

The flow characteristics of PVC resin are often judged by measuring the time required for a given amount of dry resin to flow through a standard funnel. However, considerable variation in test results have been found between laboratories though the test is conducted well within the procedural limits of ASTM 1895‐69, “Apparent Density, Bulk Factor and Pourability of Plastic Materials.” An examination has been made of the effects of funnel hole size, funnel alignment, its type metal and wall surface smoothness, filling technique, static generated, and degree of vibration. It was found that six of these seven variables need critical control, while one (alignment) has no measurable effect. It is suggested that the data presented be used for the development of an improved ASTM test for measuring the flowability of PVC resins.
Processability of rigid PVC compounds II. Comparions of extrusiometric and mixing head data. Effect of composition variables
Authors: Pukánszky Béla , Nagy Tibor Tamás , Turcsányi Béla , Tüdõs Ferenc , Krall György , Papp‐Tölgyesi E.
Published: December 2004

Various formulations of unplasticized PVC dry blends were investigated by extrusiometer and laboratory batch mixer (mixing chamber). Torque versus time curves of the mixing chamber experiments were characterized by three, essentially independent data: fusion time, equilibrium torque, and stability time, corresponding to the three distinct phases of the processing. Fair correlation was found between fusion characteristics of the compound and the energy required for its processing in the extrusiometer. The effect of composition on extrusiometric and mixing chamber data was investigated by multiple linear regression technique. The results allow prediction of the effect of recipe changes.
Stress cracking of rigid polyvinyl chloride by plasticizer migration
Authors: Lacatus Emilia , Summers James W.
Published: December 2004

Environmental stress cracking (ESC) (failure caused by crack and craze formation at a stress less than the yield stress) reduces the service life of many plastic products. This paper is concerned with ESC of rigid PVC products which are in contact with a plasticized PVC material. The ESC affect (as measured by elongation to break) is reduced at faster strain rates and by higher plasticizer viscosity, which suggests a mechanism requiring flow of plasticizer into a growing craze. Well fused (gelled) PVC made at a higher melt temperature slowed but did not eliminate environmental stress cracking. Rubber impact modifier added to the rigid PVC had no effect on ESC. Environmental stress cracking can be avoided by using flexible PVC that has a non‐migrating plasticizer or by designing the product so that rigid PVC is not stressed while in contact with plasticized PVC.
Suspension stabilizers for PVC production II: Drop size distribution
Authors: Nilsson Holger , Norviit Toomas , Silvegren Christer , Törnell Bertil
Published: December 2004

The drop size distribution of vinyl chloride in water emulsions has been studied using a photographic technique. A large difference in coalescence stability was observed between emulsions stabilized by a poly(vinyl alcohol), Rhodoviol 5/270, and those stabilized by a cellulose ether, Methocel MF50. Experiments simulating the transport of a monomer soluble initiator to the monomer phase of a coalescence stable vinyl chloride in water emulsion showed that the manner of introducing the initiator may have large consequences on the polymerization process.
Dark time yellowing of white rigid vinyl outdoor weatherable compounds
Authors: Morris Raymond A. , Prejean Thomas G. , Green John Glass
Published: December 2004

White PVC siding which has been exposed to sunlight will after removal from the sunlight develop a darker color (yellow‐brown). The longer this sample remains unexposed to sunlight the greater the color development. Testing has indicated that one or more photochemical mechanisms are occurring during this color development. A sample which appears yellow upon arrival at the home location after outside exposure can be re‐whitened by re‐exposing the sample to sunlight. Drastic color change will occur within a short period of time, usually less than 72 hours. This sample will have attained its white color with little or no yellowing visible when an original unexposed sample is held next to it. Testing conducted at an Arizona test site has confirmed these theories. Six months and one year weathered white siding samples, when measured at the test site, both experimental and commercial, showed that when the weathered samples are removed from the test racks and tristimulus values are measured daily, marked color changes occur rapidly. This paper addresses data which indicate that color development does occur but only in the very thin surface (5 to 10 micron layer) of the weathered samples. If these samples are washed and the abrasive action is sufficient to remove the surface layer, color development will no longer occur during non‐exposure to sunlight.
Thermodynamic interactions and nonlinear rheological properties of plasticized polyvinyl chloride
Authors: Foss Peter H. , Shaw Montgomery T.
Published: December 2004

The nature of thermodynamic interactions in plasticized semicrystalline materials has a profound effect on the rheological properties. In this work we investigated the effect of mixing thermodynamics on the linear and nonlinear rheological properties of plasticized poly(vinyl chloride). The stress‐dependent creep compliance has been modeled in terms of stress, temperature, concentration, and thermodynamic interaction strength.
Rheology of PVC. Part 5: Melt elasticity
Authors: Utracki L. A.
Published: December 2004

The behavior of PVC changes drastically with the temperature and the method of sample preparation. In the steady‐state shear mode, upon a decrease of the rate of deformation, the data may show either a steady increase of the shear viscosity or a leveling off to a Newtonian plateau. In the dynamic test mode, both the storage modulus, G′, and the loss modulus, G″, show an effect of the yield stress. Only at temperatures above 210°C are flow curves normal for polymer melts obtained. Rigid and nonrigid PVC formulations have been tested in Weissenberg Rheogoniometer, using steady‐state or dynamic test modes at temperatures from 140 to 220°C. It was observed that yield affects elasticity more (measured by the first normal stress difference or the storage modulus) than viscosity (expressed by the shear stress or the loss modulus). The corrected for yield plots of elastic vs. viscous parameter can be easily interpreted in terms of a composite flow.
Correlations between extrusion and injection molding process variables for PVC dry blends
Authors: Dalal V. F. , Palit K.
Published: December 2004

Although thermoplastic extrusion and injection molding have been extensively studied by a large number of authors, very little is known about the correlations between the extrusion and injection molding process variables. This paper describes the various comparable process variables between extrusion and injection molding of PVC dry blends. The Brabender extruder of 19 mm diameter and 25:1 length to diameter ratio and the Szekeley reciprocating single screw injection molding machine were used. PVC dry blends of industrial importance were prepared using a high speed mixer. The four mix formulations based on a commercial grade of PVC were used. Process variables studied during the injection molding were the melt temperature near the nozzle, injection pressure, injection speed, and energy consumption. Process variables studied during extrusion were the melt pressure at the die, power consumption, and the melt temperature at the die orifice. The correlations between the extrusion and injection molding process variables for PVC dry blends have been established.
Selecting operating conditions for PVC plastisol fusion ovens
Authors: Poppe A. C.
Published: December 2004

Gelation and ultimate fusion of layers of plastisol is a major step in producing finished spread‐coated vinyl products. An analysis of the process has been made, concentrating on heat‐up, required conditions for adequate fusion, and the associated plasticizer evaporation losses. It is further shown how the developed model can be used to help select optimal process conditions.