bluuebunny/crossref_metadata_2025_split huggingface dataset:
SIMS and XPS studies of polyurethane surfaces 2. Polyurethanes with fluorinated chain extenders
Authors: Hearn M. J. , Briggs D. , Yoon S. C. , Ratner B. D. 
Published: May 2005

AbstractA series of fluorine‐containing segmented poly(ether urethanes) and poly(ether urethane ureas), previously characterized by angular dependent x‐ray photoelectron spectroscopy (XPS) have been re‐examined using static secondary ion mass spectrometry (SIMS). Comparison of the data from the two techniques has shown that the intensity of secondary ion signals which characterize the hard and soft segments can be used quantitatively for direct analyis of the molecular composition at the surface. Moreover, the SIMS sampling depth for the conditions used has been shown to be ∼ 10 Å, significantly less than the XPS sampling depth under normal conditions, and similar to the XPS sampling depth at high glancing take‐off angle (with respect to the surface normal).
Quantitative sputtering
Authors: Zalm P. C. 
Published: May 2005

AbstractThis review discusses experimental techniques used for determining the variety of observables in ion‐bombardment induced erosion of solid surfaces. Boundary conditions for performing reproducible and accurate sputtering yield measurements are formulated. To this end, an inventory is made of the observed systematics in several phenomena accompanying sputtering and of the more regular exceptions to the general trends, also, a brief treatment of some theoretical predictions is given, based on the available literature. Following this extensive survey, the merits and limitations of a number of measurement methods, tailored to study one or more different observables, are discussed. Techniques that seem widely applicable or highly promising are emphasized.
Corrosion of stellite‐6 in lithiated and borated high‐temperature water
Authors: Hocking W. H. , Lister D. H. 
Published: May 2005

AbstractCorrosion of the cobalt‐based alloy Stellite‐6 in lithiated and borated water at 300°C with a hydrogen overpressure has been investigated. These conditions simulate a well‐defined chemistry regime in the primary circuit of an operating pressurized water reactor. The resulting oxide films were characterized using a combination of surface analytical and electron microscopy techniques. X‐ray photoelectron spectroscopy (XPS) was employed to evaluate the chemical composition of the oxide films. The morphology of the corroded surfaces was revealed by transmission and scanning electron microscopy. Scanning Auger microscopy (SAM) was used to map the distribution of elements within the oxide and underlying alloy layers. Composition depth profiles were determined by sequential ion‐sputter etching in conjunction with either XPS or SAM surface analysis. Although some differences exist, the oxide films are qualitatively similar to those described for exposure of Stellite‐6 to lithiated high‐temperature water in the absence of boron. In both cases, preferential dissolution of cobalt leads to strongly enhanced chromium concentrations within the oxide films.
Use of EN(E) spectra for quantitative AES analysis of AuCu alloys
Authors: Ichimura S. , Koshikawa T. , Sekine T. , Goto K. , Shimizu H. 
Published: May 2005

AbstractThe possibility of quantitative AES analysis using the whole EN(E) spectrum was examined for AuCu alloy samples. The EN(E) spectrum was measured under φ = 0° (normal) incidence of 10 keV electrons for the Au–44 at% Cu sample, and under φ = 0°, 30°, and 45° incidence of 10 keV primary electrons for the Au–20 at% Cu sample. Those spectra were compared with spectra which were obtained by linear combination of pure Au and Cu spectra measured under the same experimental conditions.Both measured and synthesized spectra coincided very well in the energy region lower than 1000 eV, except the region of slow secondary electrons. The results indicate that energy distribution of backscattered electrons of the AuCu alloy can be estimated well by linear combinations of pure sample spectra. They also indicate that, by comparison of the shape of the measured EN(E) spectrum with the synthesized one, the surface composition of the AuCu alloy sample can be estimated with reasonable accuracy (several % error).
The development of standards for surface analysis
Authors: Powell C. J. 
Published: May 2005

AbstractAs the use of surface analysis increases, the need for standards (reference procedures, reference data, and reference materials) becomes more urgent. This article describes recent activities and current plans of three organizations that are active in developing standards for surface analysis: Committee E‐42 on Surface Analysis of the American Society for Testing and Materials; the Surface Chemical Analysis Working Party of the Versailles Project on Advanced Materials and Standards (VAMAS); and the Working Group on Surface Analysis of the International Union of Pure and Applied Chemistry.
X‐ray spectrometry and photoelectron spectroscopy applied to the study of layered samples: SiO2 and SiOx films on InSb
Authors: Packwood R. H. , Remond G. , Holloway P. H. 
Published: May 2005

AbstractX‐ray spectrometry in the electron probe micro‐analyzer (EPMA) and x‐ray photoelectron spectroscopy (XPS‐ESCA) are used to study the composition of SiOx(1 < x ≤ 2) films of known thicknesses over InSb substrates. The analyses of SiO2 surface layers demonstrate the credibility of the model which was developed to predict the x‐ray emission in the EPMA from a surface layer on a substrate. X‐ray data indicate the presence of two chemical states in the SiOx film while three states are detected from XPS data. Both EPMA and ESCA data indicate that the SiOx compound has a composition equivalent to SiO1.12.
Electron attenuation lengths in Pb metal
Authors: Chadwick D. , Christie A. B. , Karolewski M. A. 
Published: May 2005

AbstractElectron attenuation lengths have been measured for Pb metal in the energy range 300–1200 eV. The measurements were carried out by observing the attenuation produced in a substrate (Cu, Ag or Pd) XPS signal following adsorption of a single Pb monolayer. Attenuation lengths were estimated from these attenuation factors by means of a Lambert–Beer expression. The data are represented well by the least–squares expression λ = 0.78(±0.08)E1/2 (in Å).
Characterization of PdCl2/SnCl2 metallization catalysts on a polyetherimide surface by XPS and RBS
Authors: Burrell Michael C. , Smith Gary A. , Chera John J. 
Published: May 2005

AbstractA metallization catalyst (based on the PdCl2/SnCl2 system) adsorbed on polyetherimide surfaces was characterized by x‐ray photo‐electron spectroscopy (XPS), Rutherford back scattering (RBS) and transmission electron microscopy (TEM). The overall Pd/Sn ratio increased from 0.2 to 3.8 when the initial sensitized surface was treated with the accelerator solution. XPS results indicated that before acceleration, only Sn(IV) (stannic hydroxide) is obserable, and after acceleration both metallic Sn and Sn(IV) are present; palladium is present primarily in a metallic form both before and after the accelerator step. Total Pd and Sn coverages were also obtained by RBS, and the total Pd/Sn ratios agree with the XPS surface measurements for specimens just prior to metallization. TEM micrographs showed the adsorbed catalyst consisted of particles 10–50 Å in size covering only a fraction of the surface.
Technique of sequential surface analysis with ISS and AES
Authors: Shimizu Ryuichi 
Published: May 2005

AbstractThe development of a new approach is briefly described, which enables Auger electron spectroscopy (AES) and ion scattering spectroscopy (ISS) to be performed sequentially with a commercial‐type Auger microprobe. These sequential AES and ISS measurements were applied to depth composition analysis of the altered layer formed in the surface of AlMg(60 at%) alloy under ion bombardment. A simple analysis has suggested that the ion bom‐bardment forms an altered layer in the surface, which consists of Mg‐rich composition at the top‐most atomic layer, followed by the depletion layers of Mg atoms extending over a few tens of atomic layers deep.
Direct observation of pesticides on plants using LAMMS: Imazaquin on soybean leaves
Authors: Brinen J. S. , Los M. , Kelland D. , Wallach E. R. 
Published: May 2005

AbstractLAMMS (Laser Microprobe Mass Spectrometry) has been used to observe the presence and location of a herbicide on plant lea, es. Leaves from soybean plants, sprayed with imazaquin, a member of the imidazolinone class of herbicides, at varying application rates, were examined by LAMMS without any special preparation. A rapid analysis for imazaquin was obtained confirming the suitability of LAMMS as an organic microprobe analyser. A comparison with standard chemical ionization and electron impact mass spectra of imazaquin showed evidence for laser‐induced fragmentation.
Calculations of electron inelastic mean free paths for 31 materials
Authors: Tanuma S. , Powell C. J. , Penn D. R. 
Published: May 2005

AbstractWe present new calculations of electron inelastic mean free paths (IMFPs) for 200–2000 eV electrons in 27 elements (C, Mg, Al, Si, Ti, V, Cr, Fe, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au and Bi) and four compounds (LiF, SiO2, ZnS and Al2O3). These calculations are based on an algorithm due to Penn which makes use of experimental optical data (to represent the dependence of the inelastic scattering probability on energy loss) and the theoretical Lindhard dielectric function (to represent the dependence of the scattering probability on momentum transfer). Our calculated IMFPs were fitted to the Bethe equation for inelastic electron scattering in matter; the two parameters in the Bethe equation were then empirically related to several material constants. The resulting general IMFP formula is believed to be useful for predicting the IMFP dependence on electron energy for a given material and the material‐dependence for a given energy. The new formula also appears to be a reasonable but more approximate guide to electron attenuation lengths.
SSIMS and SIMS imaging analysis of a drug delivery system
Authors: Davies M. C. , Brown A. , Newton J. M. , Chapman S. R. 
Published: May 2005

AbstractThe surface chemical analysis of a polymeric drug delivery system has been undertaken using secondary ion mass spectrometry (SIMS). The molecular specificity of static SIMS is demonstrated by the detection of the molecular ion of the drug and its principal fragments within the polymer surface in both positive and negative ion modes. SIMS imaging of molecular ions specific to the drug illustrate its uniform lateral distribution in the interfacial polymer surface network.
Texture of Raney Ni catalysts: Al‐leaching out of rapidly solidified Ni2Al3 alloys
Authors: Gros J. , Hamar‐Thibault S. , Joud J. C. 
Published: May 2005

AbstractRaney catalysts are prepared by removing Al out of NiAl alloys in boiling NaOH. The evolution of the microcrystallized Ni2Al3 structure during Al‐leaching out is essentially studied by transmission electron microscopy. The different phases of the precursor microcrystallized alloys are attacked selectively. Moreover, Al‐leaching out of Ni2Al3 occurs step by step. The Ni crystallites' orientation is directly related to the orientation of precursor alloys. An intermediate phase of Ni2Al type was observed. AES experiments were also performed before and after Al‐leaching out of undoped and Cr‐doped alloys.
LMIS‐SIMS studies of oxide scales
Authors: Moon D. P. 
Published: May 2005

AbstractA spatial resolution of <0.1 μm can be routinely achieved in secondary ion mass spectrometric analyses following the introduction of the liquid metal ion source. This has proved a powerful tool for investigating the processes of scale growth during the corrosion of metals and alloys at high temperatures. Secondary ion imaging has indicated that oxygen (tracer) transport in fine‐grained NiO scales occurs both by solid‐state diffusion along grain boundaries and by gaseous diffusion through cracks/pores. Dispersions of ceria particles in NiO scales promote oxygen penetration.
Simple angle‐resolved auger electron spectroscopy system—effective rule for measurement and tests of possibilities
Authors: Mróz A. , Mróz S. , Zagórski M. 
Published: May 2005

AbstractAn angle‐resolved Auger electron spectrometer, containing an immovable collector of electrons placed behind the hole in the fluorecent screen of the LEED optics and an electron gun fastened to the sample holder and rotating together with this sample was constructed and tested.Conditions enabling the best angular resolution, the effective rule for the measurement procedure with the use of microcomputer for controlling the measurement and storage and evaluation of the results, and a simple method of deconvolution of AES angular profiles are proposed.A result of testing measurements of polar angle‐resolved Auger electron spectroscopy (ARAES) profile for the nickel (001) face is presented.
Transfer and treatment of AES, XPS and SIMS data with a network computer station
Authors: Mathieu H. J. , Mischler S. , Vogel A. , Seiler A. , Riedl G. 
Published: May 2005

AbstractSurface and interface data by AES, XPS and SIMS are acquired either by a PDP 11–34, HP 9836U or HP 310 microcomputer using commercially available software (ESAU‐Perkin Elmer written in ASSEMBLER) or laboratory‐written software (HP BASIC version 3.0/4.0), respectively. These data are then transferred to an independent Apollo computer network station to allow off‐line treatment of the experimental data. This paper reports on the standardization of the data output files of the acquired data and their subsequent transfer and reading by an Apollo Network DN 3000 station. The program for the Apollo computer written in C‐language allows data treatment as smoothing, differentiation, integration, normalization, curve‐fitting and deconvolution on one hand, but also manipulation of data, like calculation of atomic concentration referring to tables based on handbook data. All data can be stored in a format allowing later use for data banks.
Matrix dependence of elastic scattering effects in quantitative AES and XPS
Authors: Jablonski A. , Lesiak B. , Ebel H. , Ebel Maria F. 
Published: May 2005

AbstractAn involved Monte Carlo algorithm has been developed for simulating the Auger electron and photoelectron trajectories in the surface region of different materials. The partial wave expansion method was applied to describe the electron elastic scattering. Extensive calculations were performed for C 1s photoelectrons emitted from carbon implanted in a number of materials with atomic number varying from 6 to 79. It has been found that elastic collisions influence considerably the angular distribution of photoelectrons. The asymmetry parameter describing the actual distribution decreases owing to photoelectron elastic scatering. This effect becomes more pronounced with increase of atomic number of a matrix. Two correcting parameters in quantitative XPS formalism are proposed to account for elastic scattering effects. The analytical expressions are determined to describe these correcting parameters as a function of (i) matrix atomic number, (ii) matrix atomic density, and (iii) radiation used.Similar analysis was made for carbon KLL Auger transition. Elastic Auger electron collisions were demonstrated to decrease up to 15% the Auger signal intensity. No distinct changes in angular distribution of Auger electrons were observed. An analytical expression was fitted providing the signal intensity decrease as a function of matrix atomic number and atomic density.
Ion beam induced roughness and its effect in AES depth profiling of multilayer Ni/Cr thin films
Authors: Barna A. , Barna P. B. , Zalar A. 
Published: May 2005

AbstractThe development and changes in the surface topography during ion beam etching is described by a new model taking into account the lateral displacement and collective behaviour (annihilation) of the ‘macrostep’.The model was applied to simulate thedepth dependent surface roughening taking place at the depth profiling of Ni/Cr multilayer systems with various sputtering conditions. Crystals in a channelling position were considered as sources of macrosteps. The experiments confirmed the lack of the surface roughening predicted by the model at high incidence angle of the ion beam (θ>85°)and at sample rotation. The experimental depth resolution proved to be independent of the depth if the upper layers had been removed by presputtering in ion milling equipment at θ = 86° before the conventional Auger depth profiling was carried out. A best resolution‐ (3.2 nm) has been achieved at 225 nm depth when the sample was presputtered down to 180 nm and was also rotated during Auger profiling.
Surface characterization of the deactivation of alumina catalysts used for COS synthesis
Authors: Mink G. , Bertóti I. , Németh L. , Gáti G. , Mohai M. , Székely T. 
Published: May 2005

AbstractOne of the possible routes of producing COS, an important material in organic synthese, is the CO2 + CS2 ⇄ 2COS reaction, preferably over gamma‐alumina catalysts. Under long‐term loading, however, a remarkable loss of the catalytic activity occurs.The nature of the ageing process was studied by a multi‐technique apporach on high purity [I] and on a commerical grade [II] gamma‐alumina, which latter contained Na, Ca, and S as surface impurities.On catalyst [I] weak chemisorption of CO2, CS2 and COS was observed by the volumetric method, as characterized by the isosteric heats of adsorption. Catalyst [II] chemisorbed CO2 and COS but not CS2 and showed much less catalytic activity. Gravimetric measurements have shown that adsorption of CS2 and COS leads to the surface deposition of side products. XPS studies on new, loaded and aged samples have revealed that the ageing of the catalyst is primarily caused by the deposition of sulphur and carbon with carbon in excess, presumably in CS, CS and CC environements.
The influence of Y on the structure and growth mechanism of alumina scales
Authors: van Manen P. A. , Young E. W. A. , Schalkoord D. , van Der Wekken C. J. , de Wit J. H. W. 
Published: May 2005

AbstractSmall additions of yttrium to NiAl result in a decreasing oxygen transport through the Al2O3 scale on AiAl at 1270 K, as has been shown by nuclear reaction analysis (18O(p, α)15N). A higher concentration, e.g. 0.5 wt%, has the opposite effect. Yttrium segregates to the grain boundaries in the alloy, and an enhanced Y concentration has been observed by means of EPMA in the oxide scale above the grain boundaries of the alloy. Transition aluminium oxides are shown to be formed in the initial stage at 1170 K with (glancing angle) x‐ray diffraction. Only α‐Al2O3 is formed after oxidation for several minutes at higher temperatures (1470 K). The rate of transformation of transition Al2O3 to the stable α‐Al2O3 modification depends on the oxidation temperature. The transition is shown to be retarded by the presence of Y. The primary transport processes in the Al2O3 scales are short‐circuit diffusion of oxygen and/or aluminium. At 1170 K, while transition oxides are still present, Al transport predominates. At higher temperatures, when the oxide has the α‐Al2O3 structure, oxygen transport is enhanced. This would also explain the retardation of oxygen transport by the addition of Y, since Y was found to prevent the formation of the most stable form of Al2O3.
Secondary ion emission of α‐brass alloys. The chemical effect on the ionization yield of copper and zinc
Authors: Darque‐Ceretti E. , Delamare F. , Blaise G. 
Published: May 2005

AbstractIonization yields of copper and zinc in α‐brass alloys are determined at an oxygen pressure P = 1.5 × 10−5 Torr. Two interpretations of the results are proposed, according to the bond breaking model and to the statistical environment model. The second one gives better agreement with experimental values.
Quantification of sputter depth profiles by means of wedge crater sputtering—a new technique for depth scale calibration
Authors: Voigtmann R. , Moldenhauer W. 
Published: May 2005

AbstractAn essential part of depth profile quantification is the conversion of sputtering time into depth, for which a simple method is described. It requires an ion gun providing a sufficient fine focusable ion beam. A suitable beam control produces a wedgelike distribution of ion current density in a raster field which is large compared to the ion beam cross‐section. A “wedge crater” is sputtered in this way in addition to the “normal crater” for depth profiling. The wedge crater profile obtained of surface profilometer measurements provides the sputtering time–depth relation. Moreover the sputtering rate as a function of depth may be deduced from wedge crater profile. Application of the method to SIMS depth profiling in multilayer thin film systems shows its usefulness in depth scale calibration and intensity correction. Small expenditure and universal applicability are advantages in comparison with other methods.
XPS intensity analysis for assessment of thickness and composition of thin overlayer films: Application to chemically etched GaAs(100) surfaces
Authors: Bernstein R. W. , Grepstad J. K. 
Published: May 2005

AbstractQuantification by XPS intensity analysis of thin multicomponent overlayers, like the native oxides forming on compound semiconductor surfaces, is discussed in some detail. In particular, the advantage of exploiting the attenuated emission from substrate core levels with different probing depths is emphasized, in order to obtain a precise measure for the overlayer thickness dimension. For GaAs(100) treated with different chemical etches, estimates are obtained for the thickness of the native surface oxide formed after exposure to air, of 6–8 Å. The elemental composition of the surface oxide is close to the stoichiometric metal: oxygen ratio of the bulk oxides Ga2O3 and As2O3, in perfect agreement with the measured core‐level shifts (1.4 ± 0.2 and 3.0 ± 0.1 eV for the Ga and As 2p levels, respectively). On a CF4 plasma‐etched sample, a surface reaction layer of gallium fluoride was found with a composition close to GaF2 and an estimated thickness of ∼23 Å. This paper also discusses how to determine the kinetic energy dependence of the electron escape depth, expressed in terms of an exponent m (γ Em), by working out consistent estimates for the surface oxide (fluoride) thickness via two different approaches. Values for m are obtained in the range 0.5–0.6, in excellent agreement with previously reported data on electron escape depth for semiconductors.
XPS and UPS examinations of the formation of passive layers on Ni in 1 M sodium hydroxide and 0.5 M sulphuric acid
Authors: Hoppe H.‐W. , Strehblow H.‐H. 
Published: May 2005

AbstractThe passivation of nickel has been studied in 1 M NaOH and 0.5 M H2SO4 by XPS. An electrochemical specimen preparation and transfer to an ultra‐high vacuum, without contact with oxygen, permits a detailed examination of the oxide growth with potential and time resolution. Quantitative evaluation of the data yields values for the thickness of the partial layers of the duplex film structure. The Ni/NiO/Ni(OH)2 sequence for the passive range and Ni/NiO/NiOOH sequence for the transpassive range in alkaline solutions have been confirmed by a detailed peak analysis, including angular‐dependent XPS measurements. These results are closely related to the polarization curves. An interpretation is given on the basis of a simple semiconductor model involving the results of UPS and work function measurements. The data of the acidic and the alkaline electrolytes are related to each other and their differences are explained by the increased solubility for low pH of the outer Ni(OH)2 and NiOOH layers, respectively. These properties cause thinner films in acidic electrolytes and prevent the formation of a stable NiOOH overlayer for these conditions.