bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface state of sulfated zirconia: the role of the sol–gel reaction parameters
Authors: Bianchi Claudia L. , Ardizzone Silvia , Cappelletti Giuseppe 
Published: August 2004

AbstractSulfated zirconia powders have been prepared by following a single‐step sol–gel preparative route using zirconium propoxide as the starting compound. Sulfuric acid was employed both as the sulfating agent and as the catalyst of the polycondensation reaction in the gel formation. Three different series of precursors were obtained by varying the water/alkoxide ratio in the reacting sol–gel mixture. The solvent was removed from the gel by freeze‐drying (cryogels). All the samples were calcined at three temperatures (840, 890 and 940 K) for the same time length (5 h). XPS analyses of the samples were performed by elaboration of the S 2p, O 1s, Zr 3d and C 1s spectral regions. The liquid‐medium catalytic activity of the calcined samples was tested in the esterification reaction of benzoic acid with methanol. The role played by the conditions of the sol–gel reaction in affecting the surface state and the catalytic properties of the powders is discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Preparation and characterization of CeMnO composites with applications in catalytic wet oxidation processes
Authors: Blanco G. , Cauqui M. A. , Delgado J. J. , Galtayries A. , Pérez‐Omil J. A. , Rodríguez‐Izquierdo J. M. 
Published: August 2004

AbstractA series of CeMn composites with different compositions was prepared by co‐precipitation. All samples were characterized by x‐ray diffraction (XRD), x‐ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). According to their size and chemical composition, two different kinds of particles were observed: (a) small crystallites of CeMn solid solution (<7 nm), and (b) large particles of manganese oxides with different reduction degrees (>50 nm). These results were used to explain differences between the surface and bulk compositions of the samples as well as the specific surface area. Furthermore, from XPS studies, the presence of various Mn species with different oxidation states could be stated. This fact might clarify the exceptional catalytic behaviour of the samples for the catalytic wet oxidation of toxic organic compounds. Copyright © 2004 John Wiley & Sons, Ltd.
A decomposition procedure for the determination of copper oxidation states in Cu‐zeolites by XPS
Authors: Meda L. , Cerofolini G. F. 
Published: August 2004

AbstractA procedure to determine the chemical state of copper in differently prepared catalysts is proposed. It is based on a peak decomposition of the main Cu 2p3/2 signal only, which involves both Cu(II) and Cu(I) contributions. The presence of the closest shake‐up satellite is related to the Cu(II) contribution only, in fact a linear dependence of the satellite area versus the Cu(II) area has been found. This method has been applied to characterize variously prepared catalysts and to quantify the different copper states at the surface. A molecular picture is formulated to describe a possible mechanism for copper reduction occurring during the catalyst preparation route at the zeolite surface. Copyright © 2004 John Wiley & Sons, Ltd.
Composition, structure and mechanical property analysis of DC sputtered CNi and CNxNi nano‐composite layers
Authors: Ujvári T. , Tóth A. , Kovács Gy. J. , Sáfrán G. , Geszti O. , Radnóczi G. , Bertóti I. 
Published: August 2004

AbstractCarbon–nickel (CNi) and carbon‐nitride–nickel (CNxNi) films were deposited onto native SiO2 covered Si substrates by DC magnetron sputtering from a graphite–nickel composite target using Ar or N2 for sputtering at about 2.6 Pa. The substrate temperature varied between 25 and 800°C. The structure, composition and mechanical properties of CNi and CNxNi thin layers (200–300 nm) have been investigated by high‐resolution transmission electron microscopy (HRTEM), XPS, nano‐indentation and nano‐scratch techniques. The layers were predominantly crystalline irrespective of their deposition conditions. At low deposition temperature, up to 200°C, the columnar crystallites were identified as hexagonal Ni3C, separated by narrow ‘walls’ of amorphous carbon. At substrate temperatures above 400°C, however, a graphitic multilayer arrangement of the carbon matrix was developed around the nano‐crystalline cubic nickel–nickel carbide islands. The mechanical properties of the films varied also significantly with the deposition temperature. The highest nano‐hardness of about 14 GPa was measured for the film grown at 200°C, while lower values (2–4 GPa) were obtained for high‐temperature films. High hardness values were related to the presence of Ni3C. The lowest friction coefficients were obtained for films containing high amounts of multi‐layered graphite‐like carbon developed at intermediate deposition temperatures. Copyright © 2004 John Wiley & Sons, Ltd.
Organic–inorganic hybrid nanoparticles: adsorption characteristics of polyester resins
Authors: Jesson D. A. , Abel M.‐L. , Arkhireeva A. , Hay J. N. , Smith P. A. , Watts J. F. 
Published: August 2004

AbstractThe adsorption of polyester onto organically modified silicas (ormosils) and commercial fumed silica has been compared using ToF‐SIMS. The thermodynamics of each system was examined by constructing adsorption isotherm plots which indicated that the adsorption of polyester onto one of the modified silicas used may be a two‐stage process. Adsorption onto the fumed silica is in accord with the Langmuir model. Copyright © 2004 John Wiley & Sons, Ltd.
Corrosion performance of a two‐step pre‐treatment for galvanized steel based on lanthanum nitrate and silanes
Authors: Montemor M. F. , Ferreira M. G. S. 
Published: August 2004

AbstractThe present work investigates a two‐step pre‐treatment for coil‐coated galvanized steel based on the use of La(NO3)3 and silanes. The pre‐treated surfaces were characterized by Auger spectroscopy and XPS. The analytical results give the chemical composition of the films. The work discusses the role of the functional group (sulfur) present in one of the silanes on the formation of the surface film. Corrosion resistance was assessed by electrochemical impedance spectroscopy and the results show that the pre‐treatment improves the corrosion resistance of the uncoated and coated substrates. Copyright © 2004 John Wiley & Sons, Ltd.
XPS and AES surface characterization of WC–Co after electro‐discharge machining
Authors: Stössel‐Sittig C. , Schnyder B. , Kötz R. 
Published: August 2004

AbstractThe surface of tungsten carbide with Co‐binder (WC–Co) after wire electro‐discharge machining (W‐EDM) with and without induced discolouration was investigated by XPS, AES and SEM. The measurements show that the eroded surface is at least partly covered by a layer containing Zn and Cu oxides, and also small amounts of W and Co. The Zn and Cu originate from the wire (brass wire covered with Zn) used during the W‐EDM and/or from the water, which contains Zn, Cu, W and Co from W‐EDM processes performed earlier on the same machine. The W and Co stem from the water or from the base material of the work piece. On the samples with induced discolouration a dark pattern is visible at the surface. Measurements on these samples show an increased amount of Co within the dark pattern. Copyright © 2004 John Wiley & Sons, Ltd.
Corrosion behaviour of gold surfaces protected with bonded perfluoro polyethers
Authors: Alamarguy D. , Bertoglio M. , Lécaudé N. , Noël S. , Ruaut L. , Tristani L. 
Published: August 2004

AbstractPerfluoro polyethers (PFPE) are known to offer some protection against the corrosion occurring on electroplated gold surfaces used in electrical contact applications. In this field, reliability requirements and severity of the environment of use are permanently increasing. We describe here the results of corrosion tests performed on electroplated gold coupons protected with layers of various PFPE. XPS measurements show that functionalized PFPE can be grafted to the surface. Attempts to bond the PFPE layer to the surface were also performed by exposure to UV light. Lubricant layers are shown to have better properties of protection against corrosion when they are bonded to the surface. Correlation with the mechanical and electrical performances required from such layers is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Corrosion behaviour of coated cellular material
Authors: Oriňáková Renáta , Šupicová Magdaléna , Arlinghaus Heinrich F. , Kupková Miriam , Vering Guido , Oriňák Andrej 
Published: August 2004

AbstractCellular solids are developed, improved and investigated in connection with the search for new lightweight structural materials. Interest in the applications of lightweight metal foams and novel cellular materials is rapidly increasing. They can be used as components in heat exchangers, as weight‐saving constructive elements, deformable energy absorbers, catalyst surfaces, filters, etc.Metal foams (or cellular solids) can be produced by a variety of methods. The regular‐structured cellular material might be accessible by powder metallurgical methods, using hollow powder. The metal coatings can be applied to improve the mechanical properties, surface morphology, and wear and corrosion resistance of basic materials.In this contribution the corrosion behaviour of copper + nickel coatings on the iron hollow particles has been studied. Electrodeposition of one‐component Ni and then Cu coatings and binary NiCu coatings were realized in a fluidized bed. Also the deposition of copper by cementation was investigated. The main attention was focused on the combination of electroless deposition of Cu and electrolytic deposition of Ni. The corrosion resistance of the coatings was investigated by using SEM and ToF‐SIMS methods. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative analysis of AuPd alloys from the shape of XPS spectra by the fuzzy rule
Authors: Lesiak B. , Jozwik A. 
Published: August 2004

AbstractThe quantitative analysis of solid surfaces by XPS requires the determination of spectra intensities, related to atomic concentrations, recorded for constituents of investigated systems. The most reliable method of quantitative analysis is the multiline approach. The estimation of intensities requires satellites and background subtraction. The quantitative and qualitative information from intensity or binding energy shifts may be disturbed by overlapping spectra. To avoid these problems analyses based on the spectra lineshape were developed. These analyses use methods of statistical pattern recognition possible after selecting the set of standard spectra (reference set) consisting of a set of spectra recorded for different chemical states or atomic compositions (classes). The classification quality is characterized by the misclassification rate (error rate) estimated from the reference set. Fuzzy identification referring to the fuzzy membership results in quantitative estimation of chemical states and/or atomic compositions of constituents. The application of such algorithms to different lineshapes recorded at various kinetic energies results in quantification at various information depths. In the present work the fuzzy rule for analysing lineshapes of valence band, Au 4f, Pd 3d and Pd MNN Auger spectra recorded for AuPd alloys, Au and Pd, was found to be efficient and applicable for quantitative analysis of complex systems. Copyright © 2004 John Wiley & Sons, Ltd.
Experimental and theoretical study of CVV Auger peaks of selected aluminium and carbon compounds
Authors: Timmermans B. , Hubin A. , Vaeck N. , Reniers F. 
Published: August 2004

AbstractThe Auger valence peak of Al2O3, Al and carbon compounds (graphite, fullerene, carbides) has been studied experimentally and theoretically. It is demonstrated, from a comparison of the experimental spectrum with the self‐convolution of the valence band, that the Al CVV transition in Al2O3 is an intra‐atomic transition. The behaviour of the C KVV Auger peak is shown to be intermediate between atomic and band‐like transitions. The different experimental carbide peaks could be reconstructed by a self‐convolution of the valence band and the introduction of a hole–hole repulsion term extracted from the Cini–Sawatzki equation. A non‐expected behaviour of the satellite peak at 280 eV for tungsten and chromium carbide is shown and interpreted, with a comparison with the Ramaker approach. Copyright © 2004 John Wiley & Sons, Ltd.
Sputtering rate measurements of some transition metal silicides and comparison with those of the elements
Authors: Yoshitake Michiko , Yamauchi Yasuhiro , Bose Chandra 
Published: August 2004

AbstractSputtering rates of nickel, cobalt, titanium, and tungsten silicides for Ar+ ions of 0.5–4 keV energy at a normal incidence were measured by a conventional method. Sputtering yields were calculated by approximating the atomic density of specimens from the bulk crystal structures. The sputtering yields were compared with those of pure elements in the silicides. It was found that a linear combination of the sputtering yield of each component agreed with the sputtering yields of the silicides except for tungsten silicide, in spite of the existence of preferential sputtering. Copyright © 2004 John Wiley & Sons, Ltd.
Calculation of overlayer thickness on curved surfaces based on XPS intensities
Authors: Mohai M. , Bertóti I. 
Published: August 2004

AbstractAccurate determination of overlayer thickness on samples with curved surfaces is of growing importance, especially in connection with nanometric materials systems. In this work two simple geometries are treated; closely packed spheres, well representing powder samples, and close‐packed cylinders, modelling fibrous samples. In the case of the powder samples (the arrangement is similar to the structure of the closest packed spheres) in addition to the intensity originating from curved layers of the top row of the spheres, the contribution of the partially visible spheres of the second and third rows below the top row are also considered, enhancing the accuracy of the calculations. As is shown, the method of calculation for spheres and cylinders is similar but the values of the geometry correction factors are different. The applicability of the derived geometry correction factors, based on pure geometrical considerations, is supported with experimental data obtained in two material systems: the thickness of oxide and carbonaceous contaminant layers on Si3N4 powder and Al foil were determined.These types of calculations were conveniently performed by the XPS MultiQuant program providing not only the geometry correction factors but also other parameters, such as cross‐sections, asymmetry parameters, etc. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative analysis of the x‐ray photoelectron spectrum of zirconium
Authors: Lyapin A. , Graat P. C. J. 
Published: August 2004

AbstractA procedure for the evaluation of XPS spectra is presented that allows the determination of intrinsic and extrinsic contributions to the spectra. It is based on the convolution of physically realistic functions for the x‐ray energy distribution, the core‐level main peak, the cross‐sections for intrinsic and extrinsic excitations and instrumental broadening. Surface effects have been accounted for by describing the material as a bulk substrate covered with a surface layer of the same material but with different excitation properties. The procedure has been applied to angle‐resolved Zr 3d spectra of pure zirconium. The results show that 28% of the total intrinsic intensity of the Zr 3d spectrum is not contained in the main peak. Copyright © 2004 John Wiley & Sons, Ltd.
Elastic electron backscattering from Ti: grain size effect
Authors: Lesiak B. , Zemek J. , Jiricek P. , Čerňanský M. 
Published: August 2004

AbstractMeasurements of elastic electron backscattering probabilities may provide the electron inelastic mean free paths (IMFP). This technique is known as elastic peak electron spectroscopy (EPES). The IMFPs in Ti can be determined from optical data by Tanuma et al., Gries or the TPP‐2M predictive formulae. Studies on Si and Ni show a weak influence of surface roughness, but a stronger influence of atomic composition, density, texture, average grain size and surface excitations on the IMFPs. In the present work, the elastic electron backscattering probability and IMFPs are determined for Ti exposed to sputtering and annealing. The atomic composition of Ti is determined by XPS and texture and grain size is determined by x‐ray diffraction (XRD). Ti samples exhibit no texture and grain size from 1 µm to 100 µm. For annealed samples the titanium hydride phase can be observed from the binding energy shift of Ti 2p XPS spectra. Scatter in the resulting IMFPs due to density and composition change (O and C contamination, and H from vacuum background) is negligible in comparison to scatter due to the grain size and standard used (Al and Cu). The IMFPs in Ti of grain size 1–10 µm are smaller than IMFPs in Ti of grain size 100 µm. These differences are explained by effects not accounted for in the calculations, i.e. the inelastic losses on the grain boundaries which are more pronounced in Ti of small grain size, and surface excitations which differ for Ti, Al and Cu. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative REELS of amorphous carbon and carbon nitride films
Authors: Prieto P. , Quirós C. , Elizalde E. , Sanz J. M. 
Published: August 2004

AbstractThe dielectric properties of amorphous carbon (a‐C) and carbon nitride in the 3 to 80 eV energy range were determined by quantitative analysis of reflection electron energy‐loss spectroscopy (REELS) spectra of these films. The energy loss function (ELF) of each material has been obtained by a trial‐and‐error procedure, when a good quantitative agreement between the simulated and experimental electron inelastic cross‐sections at three different primary energies (i.e. 0.5, 1 and 1.5 keV) is achieved. Kramers–Kronig transformation is then used to obtain the dielectric function. The loss functions of a‐C and CNx are characterized by two main features which result from collective excitations of the π and the π + σ electrons, respectively. The incorporation of nitrogen in the amorphous carbon matrix is discussed in terms of changes in the dielectric function. Copyright © 2004 John Wiley & Sons, Ltd.
QUEELS software package for calculation of surface effects in electron spectra
Authors: Tougaard S. , Yubero F. 
Published: August 2004

AbstractSurface analysis based on the interpretation of electron spectroscopy such as x‐ray photoelectron spectroscopy, Auger electron spectroscopy, or reflection electron energy loss spectroscopy are influenced by the inelastic scattering processes that take place when an electron moves in the region near a solid surface. The actual energy losses depend on the particular experimental situation. Thus, an electron is attracted by its image charge when it is moving in the vacuum. It will therefore lose energy even after it has left the surface and, similarly, an electron that moves in the vacuum towards the solid surface gains energy. Likewise, the scattering properties for an electron moving close to the surface are different from those of an electron moving in the bulk of the solid. In photoemission and Auger experiments the effect of the static hole will also affect the scattering probabilities of the electron in the first few ångströms as it moves away from the point of excitation. These effects will also cause the ‘effective’ inelastic mean free path to depend on the position of the electron with respect to the surface and with respect to the point of excitation. In the past years, we have developed models to describe these effects within a dielectric response theory for different cases of electrons moving near surfaces in general geometries with or without a static core hole. The formulas are quite involved with many infinite integrals and this is a major barrier for people to apply them in practice. With the purpose of making the calculations easier to perform, we have developed software (QUEELS: QUantitative analysis of Electron Energy Losses at Surfaces) that will do this in a user‐friendly way. It is hoped that with this tool at hand, we will be able to more effectively and quickly get a more complete understanding of the importance of these different effects for quantitative analysis of surface electron energy spectra. Copyright © 2004 John Wiley & Sons, Ltd.
XPS MultiQuant: multimodel XPS quantification software
Authors: Mohai M. 
Published: August 2004

AbstractA program for quantitative evaluation of x‐ray photoelectron spectra has been developed to serve as a practical tool for surface chemists. The program uses the ‘classic’ approach of quantification and requires as input the integrated intensities of the measured XPS lines. The usual correction methods and factors can be applied and controlled independently. All necessary basic data for calculations are integrated into the main library of the program. Besides the usual ‘infinitely thick homogeneous sample’ geometry model, the program is able to calculate models for layered structures, both on flat and curved surfaces. Calculation for several samples or experimental data sets can be done together. Results can be presented in several forms, such as atomic %, atomic ratio, oxide molar ratio, etc., and can be stored, printed and charted. Data can be labelled and annotated. XPS MultiQuant is equipped with a user‐friendly interface, full text help system and a ‘wizard’ for easy set‐up of calculations. Copyright © 2004 John Wiley & Sons, Ltd.
Thin film analysis in microprocessor manufacturing using Auger electron spectroscopy
Authors: Dittmar Kornelia 
Published: August 2004

AbstractIn the semiconductor industry, Auger electron spectroscopy is widely used for advanced process control and physical failure analysis. Quantified Auger depth profiles are typically based on the peak‐to‐peak intensities of the derivative Auger spectra and do not fully use the spectral information of the Auger peak. More sophisticated data processing procedures based on linear least square (LLS) fits are capable of separating superimposed Auger peaks thus providing access to any chemical state information.One example of an Auger analysis using LLS is the investigation of the interface reaction between copper interconnect and its silicon nitride based cap layer. The effect of the local environment on the silicon LVV Auger peak enables one to identify the chemical bonding of the modified copper. Another study of lead–tin alloy bump surfaces using chemical state analysis provides information about inhomogeneities of the tin oxidation and segregation. Copyright © 2004 John Wiley & Sons, Ltd.
Depth profiling of thin films of binary metal oxides
Authors: Kaciulis S. , Pandolfi L. , White R. 
Published: August 2004

AbstractOur previous results on the XPS depth profiling of binary metal oxides are compared with the new experimental data obtained for the films of SnW, MoTi and MoSn oxides. The samples have been prepared by sol–gel and magnetron sputtering techniques. XPS depth profiling of the samples has been carried out by using cyclic Ar+ sputtering at the energies of 0.5–2.0 keV. In order to compare the chemical states of constituent elements at different sampling depths, angle‐resolved XPS depth profiling has been performed on selected samples.Starting from the stoichiometric oxides on the surface and going deeper into the volume of the films, the depth profiling revealed there the presence of reduced Mo and W ions. The amount of reduced species and their distribution in depth was found to be independent of the sputtering energy and photoelectron collection angle. These metal ions in lower oxidation states were attributed to the sample preparation processes rather than to the detrimental effect of ion sputtering, dominating at higher ion energies. Copyright © 2004 John Wiley & Sons, Ltd.