bluuebunny/crossref_metadata_2025_split huggingface dataset:
XPS Study of non‐rinse chromate treatments
Authors: Yoshikawa Yukihiro , Watts John F. 
Published: May 2005

AbstractThe formation of a non‐rinse chromate coating on various metal substrates—iron, zinc and Zn–13% Ni—Has been studied by XPS. The coating contains both organic and inorganic species from the treatment bath and varies in composition depending on the amount of reducing agent added to the bath to provide the mixed Cr3+/Cr6+ stoichoimetry. The outer surface of the coating is rich in Cr3+ and there is evidence of a chemical reaction between the treatment solution and the metal substrate. An ultrahigh vacuum (UHV) taper sectioning stage has been used in conjunction with small‐area XPS to probe the interfacial chemistry between the coating and the substrate. The enhancement of Cr3+ at this interface is observed at a higher level than at the outer coating surface. These observations are interpreted on the basis of the reaction mechanism proposed for chromate coating formation.
Spectroscopic studies of the interface built up during the formation of an electropolymerized polyacrylonitrile thin film on a copper surface cathode
Authors: Viel P. , De Cayeux S. , Lécayon G. 
Published: May 2005

AbstractWe present in this work a series of result obtained on the atmospherically oxidized copper‐acrylonitrile system, our aim being to follow the deposition, by grafting and growing, of electropolymerized polyacrylonitrile film. Combining analytical means of electrochemistry—XPS, UPS and infrared reflection adsorption spectroscopy (IRAS)—allows quite an accurate description of this phenomena.The film was deposited by the imposition of a linearly growing negative tension to the copper electrode dipped in an electroyltic solution containing acrylonitrile. The polarization is stopped at different potentials of the current‐potential characteristic. These potentials correspond to the formation steps of the interface. Thus we describe, successively, the nature of the initial states (atmospherically oxidized copper) and the final states (insulating and covered polyacrylonitrile thin film of 20–30 Å) in relation to the change in density of occupied electronic superficial states.The appearance of this insulating and covering film is expressed on the current‐potential characteristic by an inhibition peak, named and passivation peak.Moreover, the non‐stoichiometric character of the superficial copper oxide is identified and permits the use of a low electrochemical potential (before the oxide electroreduction potential) to graft the polymer onto non‐oxidized sites.
Multi‐Spectral imaging in materials microanalysis
Authors: Browning R. 
Published: May 2005

AbstractMulti‐spectral imaging in materials microanalysis is reviewed, with illustrative results from scanning Auger microscopy and energy‐dispersive x‐ray imaging. A new approach to defining the signal‐to‐noise ratio for multi‐spectral images suggests that the number of resolvable signal levels increases multiplicatively with the number of orthogonal dimensions containing the signal. As the collected signal increases only as the sum of the number of dimensions, this can lead to considerable advantages of multi‐spectral over single‐channel imaging. One disadvantage of multi‐spectral imaging is the large amount of data that are collected. However, in practice, most of the signal in an image can be represented in a few dimensions using principal component analysis. An example of the use of principal component analysis shows that the information in a data set from an electron microscope image of seven energy‐dispersive x‐ray images can be viewed in two or three dimensions and can thus be efficiently presented on a windowed graphics screen.
Angular distribution of electrons elastically backscattered from surfaces
Authors: Dwyer V. M. 
Published: May 2005

AbstractThe experimentally measured angular distribution of electrons elastically backscattered from polycrystalline or amorphous solids exhibts a strong resemblance to the differential cross‐section for single‐atom elastic scattering. Consequently most analytical attempts to describe the problem, which involve some simplifying approximations to this scattering cross‐section, are inadequate in the modelling of backscattered electrons. The present paper represents an attempt to derive a simple analytical approximation that is able to describe such events. This is done by including the first scatteing event exactly and including multiple scattering events using a sort of ‘rectilinear + diffusion’ theory, which has proved to be successful for modelling the depth distribution function used in Auger and x‐ray spectroscopies.For the cases considered (Ag, Al and Cu at 1 kV), the results compare very well with both experimental data and recent Monte Carlo calculations.
Long‐duration exposure facility: Preliminary observations of the effects of low Earth orbit on MgF2, ThF4 and SiO2 optical materials
Authors: John P. J. , Day A. E. , Haas T. W. , Trumble T. M. 
Published: May 2005

AbstractNomarski photography and x‐ray photoelectron spectroscopy have been applied to the study of the effects of low Earth orbit on MgF4 and SiO2 optical coatings. These sample coatings were part of NASA's Long Duration Exposure Facility (LDEF), which flew in low Earth orbit for nearly 6 years. Numerous craters, cracks and other artifacts of the space environment were observed. Oxidation of the fluoride films was also noted.
Electropolymerization of pyrrole on Fe and Pt electrodes in methanol and acetonitrile. Evidence of interfacial layers resulting from accumulation and decomposition of the supporting electrolyte
Authors: Ferreira C. A. , Aeiyach S. , Delamar M. , Lacaze P. C. 
Published: May 2005

AbstractThe partial decomposition of PF6− during pyrrole electropolymerization in methanol and acetonitrile on Fe and Pt electrodes is demonstrated using XPS analysis. A complex mixture of PF6−, fluorides of phosphorus and metal oxides is shown to exist in the interfacial region, probably resulting in a weak cohesive layer unfavourable to the adhesion of polymer films.
Imaging of polymer surfaces using X‐ray photoelectron spectroscopy
Authors: Zupp Terry A. , Fulghum Julia E. , Surman David J. 
Published: May 2005

AbstractApplications of x‐ray photoelectron spectroscopy imaging in the analysis of heterogeneous polymer surfaces are evaluated using a sample containing tetrafluoroethylene plasma‐deposited onto polyethylene. The C 1s and F 1s images acquired using non‐monochromatic Mg Kα and monochromatic Al Kα x‐ray sources are used to demonstrate good charge stabilization, as confirmed by small‐area spectra. The use of non‐monochromatic flood sources vs. monochromatic focused x‐ray ray sources for image acquisition is discussed. The use of the valence band region for imaging is also demonstrated.
Composition and physical properties of thin a‐C:N and a‐C:N:H films deposited by ion beam techniques
Authors: Zorman Christian A. , Shiao Jeansong , Heidger Susan , Hoffman Richard W. 
Published: May 2005

AbstractThin a‐C, a‐C:N, a‐C:H and a‐C:N:H films were deposited onto silicon, glass and graphite substrates using ion beam techniques. Rutherford backscattering spectroscopy and elastic recoil detection analysis were performed in order to determine their atomic composition. The hardness of these films was measured using a Vickers hardness diamond indenter. The as‐deposited a‐C:H and a‐C:N:H films were characterized using optical absorption spectroscopy, while the a‐C and a‐C:N films were studied by Raman spectroscopy. A shift of the absorption edge toward the lower energy region and a lower gap of a‐C:N:H films was observed. The Raman spectra of a‐C:N films show an increase in the I(D)/I(G) ration, as compared to those of non‐nitrogenated diamond‐like carbon films. A possible structure is suggested.
Calculations of electron inelastic mean free paths. V. Data for 14 organic compounds over the 50–2000 eV range
Authors: Tanuma S. , Powell C. J. , Penn D. R. 
Published: May 2005

AbstractWe report calculations of electron inelastic mean free paths (IMFPs) of 50–2000 eV electrons for a group of 14 organic compounds: 26‐n‐paraffin, adenine, β‐carotene, bovine plasma albumin, deoxyribonucleic acid, diphenylhexatriene, guanine, kapton, polyacetylene, poly(butene‐1‐sulfone), polyethylene, polymethylmethacrylate, polystyrene and poly(2‐vinylpyridine). The computed IMFPs for these compounds showed greater similarities in magnitude and in the dependences on electron energy than was found in our previous calculations for groups of elements and inorganic compounds (Papers II and III in this series). Comparison of the IMFPs for the organic compounds with values obtained from our predictive IMFP formula TPP‐2 showed systematic differences of ∼40%. These differences are due to the extrapolation of TPP‐2 from the regime of mainly high‐density elements (from which it had been developed and tested) to the low‐density materials such as the organic compounds. We analyzed the IMFP data for the groups of elements and organic compounds together and derived a modified empirical expression for one of the parameters in our predictive IMFP equation. The modified equation, denoted TPP‐2M, is believed to be satisfactory for estimating IMFPs in elements, inorganic compounds and organic compounds.
Analysis of TdeV guard limiters by surface spectroscopies
Authors: Li X. L. , Paynter R. W. 
Published: May 2005

AbstractIn this study we have analysed coupons cut from one of the internal components of the TdeV tokamak, the stainless‐steel side sheeting of a guard limiter, which was removed when the tokamak was modified at the end of 1988. Depth profiles of the accumulated layer of contaminants have been compiled by a variety of surface analytical techniques, including Auger electron spectroscopy, elastic recoil detection and scanning electron microscopy.Melting, arcing, bubbles and large exfoliated layers of coating are observed on the surface of the guard limiter. The damage becomes less severe with increasing distance from the plasma and disappears near the wall. The deposits consist of a mixture of carbon, oxygen, stainless steel and Inconel. Most of the deposited impurity is carbon. Of the deposited metal mixture, only about 6% is Inconel, implying that metal impurities originated mainly from the stainless‐steel foils that form a frame around the guard limiter, whereas the Inconel bars were relatively untouched. The metal concentration is a maximum at the surface, coinciding with the maximum concentration of oxygen. Metal carbide appears to be formed with the metal deposits near the surface and at the interface with the substrate, whereas the middle layer consists mainly of ‘amorphous’ carbon.
Present limits to the calculation of auger line intensities for film–substrate systems
Authors: Lee C. L. , Gong H. , Ong C. K. 
Published: May 2005

AbstractA new and simple algebraic expression for calculation of backscattering factors in the film‐substrate systems has recently been proposed. The limits of its use with the Gryzinski ionization cross‐section to calculate Auger line intensities were, however, not throughly discussed. We have examined more closely its range of validity using Monte Carlo simulation and recent experimental data available. Film‐substrate systems of carbon films on Cu, Sn and Ta substrates and Cu films on C, Sn and Ta substrates were investigated. Our results have indeed shown that there are disagreements. Contributing factors to some of the disagreements include the proposed backscattering factor expression and the ionization cross‐section used. New proposals for quantification were suggested using an alternative interpolation factor taking into account substrate scattering behavior and the Bethe ionization cross‐section. Results of the new proposals did show significant improvements with the use of the Bethe ionization cross‐section for the case of carbon film–substrate systems. Results for Cu film–substrates were not conclusive, with only one evident improvement for Cu/C using the Bethe cross‐section.
SIMS depth profiling with sample rotation in a cameca IMS 3F
Authors: Sykes D. E. , Chew A. 
Published: May 2005

AbstractThe improvements in depth resolution and the suppression of sputter‐induced surface topography obtained using sample rotation during SIMS depth profiling in a Cameca IMS 3F are described. The sample rotation was achieved using a stage that maintains the alignment of the ion optical and rotational axes whilst allowing x–y translation to any position on the sample surface. The material systems studied were a Be‐spike‐doped GaAlAs sample grown by molecular beam epitaxy and a sputter‐deposited film of aluminium on silicon. Significant improvement in depth resolution is shown for buried features in both materials; the sputter‐induced ripple topography was suppressed in the analysis of the GaAlAs; for the aluminium on silicon sample the surface roughening was much reduced but some topography was still present even with sample rotation. The apparent interface width between the 1 μm thick aluminium film and the silicon substrate was reduced from 310 to 45 nm.
Scanning tunnelling microscopy study of tip bias‐induced surface changes on platinum
Authors: Hoffmann‐Millack Britta , Steer William S. 
Published: May 2005

AbstractUsing scanning tunnelling microscopy, platinum wire surfaces have been studied in air and argon under a range of tip bias voltages. It was found that surfaces generally appear smoother with small bias voltages and develop apparent blistering at higher biases. No threshold voltage for the onset of surface roughening has been detected, the process increasing gradually. An explanation for this behaviour is suggested and conclusions are drawn concerning optimum scanning conditions.
Surface analysis of oxidized aluminium. 2. Oxidation of aluminium in dry and humid atmosphere studied by ESCA, SEM, SAM and EDX
Authors: Olefjord Ingemar , Nylund Anders 
Published: May 2005

AbstractPure Al (99.998%) and technically pure Al (99.5%) were oxidized in oxygen at room temperature, 250°C and 500°C. The oxidized samples were exposed to a humid atmosphere (80% RH) at room temperature for times ranging from 1 day to 1 month. The reaction products were analysed by ESCA, scanning Auger microscopy, energy‐dispersive x‐ray spectroscopy (EDX) and SEM. The thicknesses of the surface oxides formed during oxidation for 5 h at the same temperatures as above are 15, 22 and 65 Å, respectively. After exposure of the technically pure Al material to a humid atmosphere the analyses show localized corrosion and formation of hydroxide at noble precipitates like Al3Fe and α‐AlFeSi. The distribution of hydroxide particles on oxidized Al can be recorded by SEM owing to the fact that the secondary electron yield of Al2O3 is larger than the yield of Al(OH)3. Exposure of pure Al, preoxidized at room temperature, to a humid atmosphere for 1 week causes a growth of the oxide thickness from 15 to 22 Å. The corresponding growth in a dry atmosphere for the same time is only 1 Å. It is suggested that the growth in a humid atmosphere is due to hydration of Al2O3. Thereby, the oxide becomes thinner and oxidation of Al occurs. The Al(OH)3 formed by hydration is decomposed to Al2O3 in the ultrahigh vacuum (UHV) system and is therefore detected as an oxide growth.
An analytic form for the SIMS response function measured from ultra‐thin impurity layers
Authors: Dowsett M. G. , Rowlands G. , Allen P. N. , Barlow R. D. 
Published: May 2005

AbstractWe present an analytic form for the response function measured in a SIMS depth profile of an impurity layer less than 1 nm wide (a delta layer). Although the process used to evolve the function can be justified on physical grounds, we make no claim that the justification is rigorous or that the function is universal. At present we examine its use in making a consistent and utilitarian definition of frequently employed resolution parameters. The function is found to give an accurate fit (lying everywhere within the statistical noise on the profile over several orders of magnitude in signal intensity) to responses from boron, antimony, germanium and isotopically pure silicon deltas in a silicon matrix, and to silicon, aluminium and beryllium deltas in gallium arsenide. The fit is also good over the full primary ion energy range examined (1–11 keV). There are four fitting parameters for a normalized data set, one related to the depth of the delta below the surface and three independently related to depth resolution. The function has an analytic Fourier transform, and may be used as a smooth, noise‐free substitute for the measured data in profile synthesis (convolution) and in deconvolution whenever convolution is a valid model for the SIMS measurement process.
Sputter‐Induced effects on quantitative GD‐OES depth profiles from hot‐dip zinc‐coated steel
Authors: Karlsson Jörgen , Hörnström Sven Erik , Klang Hans , Nilsson Jan‐Olov 
Published: May 2005

AbstractDepth profiling using glow discharge optical emission spectroscopy (GD‐OES) is sometimes used by the steel industry to determine the composition of the zinc coating of hot‐dip galvanized steel. It has been observed that the shape of the aluminium profile from an intermetallic phase between the zinc coating and the steel varies from sample to sample, and that the phase is much wider than expected. We have used scanning Auger microscopy (SAM) to study the surface composition and topography of GD‐OES sputtering craters. A surface roughness is introduced during sputtering that considerably deteriorates the depth resolution. The shape of the GD‐OES depth profile in the intermetallic region is related to the microstructure of the zinc coating.
Thermodynamic effects on ion‐beam mixing in SiC–metal systems
Authors: Laidani N. , Calliari L. , Kelly R. , Miotello A. 
Published: May 2005

AbstractThe ion‐beam mixing of SiC‐coated Fe, Cr, Ni, Cu, and stainless steel was investigated, by means of Auger electron spectroscopy, to determine the role of thermodynamics in the process. Both inert (Ar+) and reactive (N+) ions were used at either 30 keV or 160 keV incident energy. A mechanism involving thermally activated motion of bombardment‐induced defects appeared relevant to the onset of a chemical bias in the mixing. Further, the formalism established for describing ion mixing, based on Darken's analysis of chemical interdiffusion coefficients, provided a quantitative interpretation of the results.
Study of passive film formation on Cu–Ni 70/30 alloy in seawater at high temperature
Authors: Beccaria A. M. , Wang Y. Z. , Poggi G. 
Published: May 2005

AbstractThe corrosion mechanism of Cu–Ni 70/30 alloy in quiescent seawater at 80°C with a dissolved oxygen content of .3.0 ppm was studied with electrochemical and free corrosion tests. The passive films formed on free corroded specimens after an exposure time of 10 min–360 h were analysed with XPS.Free corrosion tests show that Cu–Ni alloy undegoes copper‐selective dissolution; the kinetics of the dissolution process are governed by a transport‐limited mechanism. Electrochemical tests show that the overall corrosion process is under cathodic control and that the reduction of dissolved oxygen is the most important parameter of the corrosion process. X‐ray photoelectron spectroscopy shows that the composition of the passive films changes by changing the exposure time. The main components of the passive films formed on metallic surfaces are Ni compounds after the shorter exposure time and Cu compounds after a longer exposure time.
Factor analysis of Fe M2,3 VV spectra of oxidizing iron: The role of the background in the emergence of ghost components
Authors: Kooi Bart J. , Somers Marcel A. J. 
Published: May 2005

AbstractThe influence of the (correction for the) background in AES spectra on the results of factor analysis (FA) was investigated. To this purpose a set of experimental spectra for the Fe M2,3VV transition, obtained on the oxidation of pure iron, and sets of look‐alike simulated spectra, using a linear combination of two elastic components superimposed on background components, were analysed with FA after different types of treatment of the spectra prior to FA, e.g. differentiation or removal of a particular type of background. In the sets of simulated spectra the roles of a background due to the secondary electron cascade and that due to the inelastically scattered electrons were investigated separately. It was observed that for both types of backgrounds additional principal components with respect to the two elastic components arise, irrespective of the considered treatment of the spectra prior to FA. Results obtained for the experimental set and for the simulated sets with a background originating from the secondary electron cascade were very similar. In the simulated spectra, the origin of the additional components could be identified unambiguously as (an inadequate correction for) the background due to the secondary electron cascade. It is likely that the same origin applies to the additional (third) component emerging on FA of the set of experimental Fe M2,3 VV spectra.
XPS and static SIMS studies of copoly(ether–esters) containing mixed polyether soft blocks
Authors: Burrell Michael C. , Bhatia Qamar S. , Michael R. S. 
Published: May 2005

AbstractThe surface compositions for a series of copoly(ether–esters) are determined from XPS and static SIMS measurements. The copolymers consist of a polybutylene terephthalate (PBT) hard block and a mixed soft block of two of the following polyethers—poly(propylene glycol) (PPG), poly(tetramethylene) oxide (PTMO) and poly(ethylene oxide) (PEO). The surfaces of all the copolymers are enriched in the total polyether soft blocks. Quantification of XPS intensities shows the presence of both polyethers at the surface of these mixed soft‐block copolymers, in relative amounts close to the bulk formulations. In the static SIMS measurements, direct observation of characteristic fragment ions related to the specific polyethers confirms their presence and relative abundance in the surface.
Auger quantitative analysis of brass via target factor analysis
Authors: Calliari L. , Gonzo L. , Micheli V. , Tiscione P. 
Published: May 2005

AbstractThe composition of a brass alloy is determined through target factor analysis (TFA) of Auger data. In spite of spectral interference between Cu and Zn transitions, quantitative information is derived from both the low‐energy and the high‐energy part of the brass spectrum. From the less surface‐sensitive high‐energy region, the nominal composition of the alloy is recovered, whereas from the more surface‐sensitive low‐energy region a definitely higher Zn/Cu ratio is found. This is interpreted in terms of surface segregation of Zn brought about by in situ scribing for surface cleaning.
Application of angle‐resolved XPS algorithms to overlayers and concentration gradients
Authors: Tielsch Brian J. , Fulghum Julia E. 
Published: May 2005

AbstractAngle‐resolved XPS data from three different sample types was used to compare algorithms for the determination of overlayer thickness and/or concentration gradients. Samples included SiO2 on Si, epitaxial Si0.862Ge0.138 on Si and As implanted in Si. Two algorithms for the determination of overlayer thickness (the relative ratio and patchy overlayer algorithms) and two algorithms based on Laplace transform or regularization methods for the evaluation of concentration gradients were evaluated. For the SiO2 and As‐implanted samples, results representative of the sample type were obtained. However, the composition profiles from the Laplace algorithms showed the expected sharp interface between the Si substrate and the SiGe overlayer, while the regularization algorithm did not. All of the algorithms have correlating parameters, and absolute results depend upon the normalization method, electron attenuation length values and other algorithm‐dependent terms. A comparison of angle‐resolved XPS data from different samples thus requires careful and consistent choices for algorithm parameters.