bluuebunny/crossref_metadata_2025_split huggingface dataset:
Segregation aspects at the fracture surfaces of 8 wt.% yttria‐zirconia thermal barrier coatings
Authors: Ingo Gabriel Maria , Padeletti Giuseppina 
Published: May 2005

AbstractSmall‐area x‐ray photoelectron spectroscopy (SAXPS), small‐area x‐ray‐induced Auger electron spectroscopy (SAXAES) and secondary ion mass spectrometry (SIMS) have been used to investigate segregation phenomena at fracture surfaces of 8 wt.% Y2O3–ZrO2 plasma‐sprayed thermal barrier coatings (TBCs) as a function of temperature up to 1620 K. The results show the complex microchemistry of the fracture surfaces, where segregation of bulk dissolved impurities such as Si, Al, Fe and Na and of the stablilizing yttrium oxide takes place from 1170 K. The SAXPS and SAXAES results indicate that the chemical composition of the segregated phase is ascribable to an infinite chain silicate of sodium with a variable presence of iron, yttrium and aluminium as a function of temperature. The SIMS ion images suggest, further, that aluminium and yttrium segregate both at the silicate segregated regions as well as separately. The effect of impurity segregation phenomena on the thermal shock resistance of the TBCs is discussed.
Factor analysis as a tool to deconvolute auger spectra of tungsten nitrides and carbides
Authors: Reniers F. , Hubin A. , Terryn H. , Vereecken J. 
Published: May 2005

AbstractFactor analysis was applied to Auger sputter profiles of tungsten carbide and nitride samples. It is shown that very weak differences in the shapes of the metal peaks due to the presence of C and N can be isolated unambiguously by factor analysis. The different chemical states of carbon, nitrogen and tungsten were clearly identified.
Combined surface analytical and electrochemical study of the formation of passive layers on Fe/Cr alloys in 1 M NaOH
Authors: Hoppe H.‐W. , Haupt S. , Strehblow H.‐H. 
Published: May 2005

AbstractCombined XPS and electrochemical studies of the passivation of Fe/Cr alloys have been performed in 1 M NaOH. Argon ion sputtering and a specimen transfer within a closed system provide a reliable situation with well‐controlled starting conditions for passivation transients and surface analytical studies with sufficient time resolution, especially at negative electrode potentials. The results for Fe/Cr are discussed on the basis of previous studies with the pure elements. The extremely slow dissolution of Cr(III) oxide and its relatively negative formation potential are responsible for the excellent passive behaviour of these alloys. Chromium(III) stabilizes Fe(II) and Fe(III) within the passive layer. Any Cr(III) enrichment is a consequence of preferential Fe dissolution. In 1 M NaOH the reduced solubility of Fe(III) oxide leads to an overlayer consisting mainly of Fe(III)oxide/hydroxide. The formation and oxidation of Fe(II) follows similar characteristics as found for oxide films on pure iron. Iron oxide components may, however, not be reduced to metal, as in the case of passive layers on pure Fe. These studies show that not only the final stationary state but also the process of passivation and the chemical changes of passive layers with potential and time can be investigated with XPS. Thus, one can obtain more reliable insight into the complicated processes leading to passivity.
Preparation of thin AlOx (0 ≤ x ≤ 1.5) films on gold and polycarbonate characterized by XPS, EPMA, AFM and TEM
Authors: Csanàdy A. , Pitton Y. , Mathieu H. J. , Kessler K. , Fuchs R. , Textor M. 
Published: May 2005

AbstractThe parameters controlling reactively deposited aluminium oxide films on Au and polycarbonate substrates have been investigated under typical PVD conditions of varying O2 flux and deposition rate of thicknesses up to 150 nm. Chemical and physical characterization have been carried out by the use of x‐ray photoelectron spectroscopy (XPS) combined either with sputter profiling or by variation of the emission angle (ARXPS), electron probe microanalysis (EPMA), atomic force microscopy (AFM) and by transmission electron microscopy (TEM). Correlation between XPS, EPMA, AFM and TEM points to island formation during co‐deposition of crystalline metallic Al and amorphous oxide areas if the O2 flux is insufficient. For high O2 fluxes, completely amorphous Al2O3 films are found. No intermediate phase between Al metal and Al2O3 was detected.
Effect of Ga+ backscattering in static SIMS
Authors: Zehnpfenning J. , Niehuis E. , Rulle H. , Benninghoven A. 
Published: May 2005

AbstractWe report on the origin of detected Ga+ ions in static SIMS measurements. The fraction of inelastically reflected Ga+ ions has been determined by applying primary ion pulses of two different gallium isotopes in appropriate time‐of‐flight (ToF) SIMS experiments. The fraction of backscattered and detected Ga+ ions is in the 10−3−10−6 range, depending on target material and surface contamination. The Ga+ signals observed in static SIMS experiments mainly originate from backscattered primary gallium ions.
Combined depth profile analysis with SNMS, SIMS and XPS: Preferential sputtering and oxygen transport in binary metal oxide multilayer systems
Authors: Albers Th. , Neumann M. , Lipinsky D. , Wiedmann L. , Benninghoven A. 
Published: May 2005

AbstractDepth profile measurements of binary metal oxide multilayer systems have been performed by combined SIMS, SNMS and XPS. The combination of data about the particle fluxes and thus the bulk stoichiometry by SNMS, the ionic fluxes by SIMS, and the surface composition and the oxidation state of the metals by XPS provides a detailed insight into the mechanism of preferential sputtering in these systems. We present results on the systems Al2O3/TiO2 and SiO2/HfO2. The signal behaviour at the interfaces cannot be explained by preferential sputtering alone, but must include an oxygen transport mechanism due to chemical driving forces. By comparison of these systems with four other multilayer systems, we have developed a model of combined preferential sputtering and oxygen transport which accounts for the experimental results. The investigated systems can be classified according to their metal/oxygen sputter yield ratio, the degree of preferential sputtering, and the heat of formation of the oxide.
Crystalline effects on depth resolution in AES depth profiling
Authors: Kajiwara K. 
Published: May 2005

AbstractAn evaluation of the depth resolution of sputter‐assisted Auger electron spectroscopy (AES) has been studied for semiconductor superlattices. Zalar et al. have shown that sample rotation is effective in improving the depth resolution of AES depth profiling. Multilayers with two kinds of crystalline states were prepared to test the effectiveness of sample rotation. First, a microcrystalline Zr/Nb (10 nm/10 nm) multilayer was deposited by dc‐sputtering. Secondly, an AlAs/GaAs (10 nm/9 nm) and an InP/InGaAs (3 nm/3 nm) single crystalline superlattice were grown by metal‐organic chemical vapor deposition.AES depth profiling with Ar+ ion sputtering was performed on these multilayers with and without sample rotation. Comparing the rotational depth profiling results with those obtained on stationary samples, it is found that, in the cases of the Zr/Nb and the InP/InGaAs multilayers, the depth resolution was considerably improved by sample rotation while in the case of AIAs/GaAs multilayer the depth resolution was only little improved by sample rotation. It is shown that the effectiveness of sample rotation strongly depends on the crystalline states of samples and on the degree of preferential sputtering.
XPS analysis of polypropylene grafted with acrylic monomers
Authors: de Lange P. J. , Gebben B. , Elfrink P. J. 
Published: May 2005

AbstractX‐ray photoelectron spectroscopy (XPS) has been used to characterize the surface of nonwoven polypropylene grafted with acrylic monomers. Results obtained for the non‐ionic hydroxyethyl methacrylate (HEMA) and 2,3‐dihydroxypropyl methacrylate (DHPMA) are very clear and in agreement with those of CWST (critical wetting surface tension) measurements. Estimation of the thickness of the grafted layer from the XPS measurements is consistent with results from a simple theoretical calculation. The results obtained for the ionic methacrylic acid (MAA) deviate and are not in agreement with those of the CWST measurements. This is not understood, but might be attributed to the folding of the more polar MAA chains under dry conditions, leading to incomplete coverage of the surface. A second explanation is a higher contribution of grafting in the bulk of the polymer. Both explanations are supported by grafting of MAA from methanol as solvent.
Argon bombardment‐induced topography development on InP
Authors: Malherbe J. B. , van der Berg N. G. 
Published: May 2005

AbstractInP (100) samples, n‐doped with S atoms to 4 × 1018 cm−3 and to 6 × 1018 cm−3, were bombarded by low energy (0.5 to 5 keV) argon ions. After bombardment, the surfaces exhibited the formation of small protrusions on the surface. These sputter cones appeared after an ion dose of the order of 1015 Ar+ cm−2. These cones grow slowly with increasing ion dose. At a constant dose, the sizes and density of these cones depended on the angle of incidence of the argon ions. At an ion incidence angle of approximately 41°, a maximum was obtained in the topography development. The sputter‐induced morphology had, at a constant dose density and angle of incidence, only a slight dependence on the energy of ions in the 0.5 to 5 keV range. Sputtering at the two lower energies (0.5 and 1 keV) resulted in an increase in the surface roughness compared to the higher ion energies. No synergic effects of simultaneous electron and ion bombardment were observed in the as‐factory received samples. When the angle of incidence of the bombarding ions was kept fixed, the degree of sputter‐induced surface topography remained constant for different relative orientations of the (100) InP substrates. Seeding cones were observed under appropriate conditions, but were not systematically investigated.
Investigation of thin films by soft X‐ray fluorescence and by total electron yield measurements
Authors: Ebel H. , Mantler M. , Svagera R. , Kaitna R. 
Published: May 2005

AbstractWe propose a description of the sampling depth (λ) of total electron yield experiments (TEY) in terms of kinetic Auger electron energies. This empirical response results from literature data1 – 6 on low energy (<2 keV) and from our own experiments performed on thin layers of Cu on Fe substrates and on thin layers of AlxGa1 − xAs on GaAs substrates at energies of approximately 5to 8 keV. From these investigations we estimate a sampling depth of 74 nm for Ga KLL Auger electrons in AlxGa1 − xAs. For comparison, the sampling depth of x‐ray fluorescence analysis (XRF) for Al Kα radiation in AlxGa1 − xAs is 400 nm.Both methods (XRF and TEY) were joined for quantitative determination of the thickness t and the Al content x in thin AlxGa1 − xAs layers on GaAs substrates. Al Kα fluorescence radiation excited by polychromatic x‐radiation and the jump of the total electron yield in the vicinity of the GaK‐edge were used in our analytical model. The validity of this model is verified by a comparison of our results with the expected values (known from preparation of the layers).
The growth mode of copper and iron for the Cu/Fe and Fe/Cu interfaces
Authors: Polzonetti G. , Di Castro V. , Furlani C. 
Published: May 2005

AbstractThe early stages of Cu and Fe metal growth on respectively Fe and Cu polycrystalline substrates have been studied at room temperature by photoemission spectroscopy. Analysis of the Cu3p and Fe3p core levels peaks intensity as a function of the metal overlayer coverages has been made for both systems. Formation of the first atomic layer followed by clusters aggregation has been detected as the mode of growth for Cu on Fe as well as for Fe on Cu. Previous results obtained by UV‐photoemission have been confirmed with the evidence for the absence of interdiffusion and surface alloy formation at the interface.
XPS and AES study of Al2O3/Ti6Al4V interface: Influence of oxidation and nitruration of the metal surface
Authors: Delogu P. , Dikonimos‐Makris T. , Giorgi R. , Lascovich J. , Caneve L. , Scaglione S. 
Published: May 2005

AbstractImportant properties of the coating/substrate combination like hardness, stress and, in particular, adhesion rely partly on the morphology and microstructure of the interface, which is often physically and chemically different from the substrate as well as from the coating.The aim of this work is to study the influence of the chemical state of the metal surface on the structure of the interface Al2O3/Ti6Al4V, obtained by deposition via sputtering of the ceramic.For this purpose three different surface treatments of the substrate were performed: air oxidation, cleaning by Ar+ sputtering and nitrogen ion implantation.The chemical composition of the treated surfaces was assessed by x‐ray photoelectron spectroscopy, while the composition of the interfaces was investigated by Auger electron spectroscopy depth profiling.
Surface structure of the PAN‐based carbon fibres studied by the scanning probe microscopy (SPM)
Authors: Zhdan P. A. , Grey D. , Castle J. E. 
Published: May 2005

AbstractScanning tunnelling microscopy (STM) and scanning force microscopy (SFM) have been applied to characterize the surface topography of carbon fibres before and after activating electrochemical treatment. Electrochemical activation is seen to have a significant effect on the structure of the surface layers. The influence of scanning parameters on STM and SFM images was examined and it was found that alteration of the scanning direction allows important additional information about surface structure of carbon fibres to be obtained. It also makes it possible to estimate the contribution of the artefacts to resulting images. The results indicate the great potential of both STM and SFM for three‐dimensional surface characterization of carbon fibres.
STM characterization of InP gratings for DFB laser fabrication
Authors: Meneghini G. , Picotto G. B. , Gentili M. , Grella L. 
Published: May 2005

AbstractDiffraction gratings for distributed feedback (DFB) laser devices were characterized by means of a scanning tunnelling microscope (STM) operating in air. The gratings, made of n‐doped InP semiconductor, were prepared using holographic and electron beam lithography (EBL) exposures followed by reactive ion etching (RIE) to transfer the photoresist pattern into the wafer. The grating surfaces were partly shadow‐coated with a thin gold layer, and the line patterns were STM‐imaged on both the coated and non‐coated InP surfaces. Pitches of first‐ and second‐order gratings, including λ/4 phase shift lines and the depth of the holographic second‐order grating, were measured by means of a precisely calibrated piezo‐capacitive STM head, a UV diffractometer and a scanning electron microscope (SEM). A precise STM characterization of the coated line patterns was achieved. As regards the non‐coated surfaces, reliable STM measurements of InP grating pitches were performed without any sample preparation and surface contamination.
Identification of the fixed nitrogen containing species during the photo‐oxidative fixation of molecular nitrogen on UV‐illuminated TiO2surfaces
Authors: Navio J. A. , Real C. , Bickley R. I. 
Published: May 2005

AbstractUltraviolet photoexcitation of hydroxylated TiO2surfaces in the presence of a mixture on N2/O2gas (air) produces some adsorbed nitrogen oxide species which were previously assigned indirectly as probably N2O22−. Direct assignment is now reported here. From comparisons of the thermodesorption profiles and the XPS results from polycrystalline Na2N2O2and from the corresponding data obtained from TiO2surface upon which Na2N2O2had been allowed to adsorb with the thermodesorption profile and XPS data obtained from the photo‐induced fixation of nitrogen on TiO2, it can be concluded that the principal species formed during the photo‐oxidative fixation of molecular nitrogen on TiO2is hyponitrite anion, N2O22−.
Use of ion implantation to study the corrosion of an austenitic steel in an oxidizing/sulphidizing atmosphere
Authors: Stroosnijder M. F. , Norton J. F. 
Published: May 2005

AbstractThe beneficial effect of the addition by ion implantation of cerium on the corrosion behaviour of a 32Ni‐20Cr austenitic steel in a mixed oxidizing/sulphidizing environment, at 700 °C has been studied. Emphasis was placed on the initial stages of the corrosion process using a wide range of surface analytical techniques. Comparison is made with unimplanted material and also with xenon‐ and chromium‐implanted steel. The latter had no significant effect. In contrast Ce ion implantation improved the corrosion behaviour, which is probably due to a change in the nucleation stage of corrosion, leading to an improved quality of the oxide layer forming under the initial corrosion products. Factors which might contribute to this are discussed.
Application of reflectance spectrophotometry to the study of copper (I) oxides (Cu2O and Cu3O2) on metallic substrate
Authors: Lefez B. , Kartouni K. , Lenglet M. , Rönnow D. , Ribbing C. G. 
Published: May 2005

AbstractThe aim of this study is to characterize the compounds grown on copper during the oxidation at low temperature (T < 523 K) by optical methods: photoluminescence and UV‐Visible‐NIR diffuse reflectance spectroscopy. Two cuprous oxides Cu2O and Cu3O2 have been studied. The absorption of Cu2O films in the range 450–630 nm is mainly due to non‐stoichiometry bands associated with copper and oxygen vacancies. Cu3O2 is characterized by an optical band gap greater than that of Cu2O (respectively 2.25 and 1.95 eV) and by an intense luminescence emission at 760–780 nm. Cu3O2 may be considered as a gross defect structure of Cu2O (a = 0.427 nm, a = 0.431 nm). The experimental approach of the oxidation mechanism reveals that at 423 K Cu2O is the primary product which later on is transformed into Cu3O2. Experimental and calculated optical absorption curves disclose the nucleation of CuO inside the cuprous oxides layer for oxidation in the range 473–523 K.
Influence of the Cs concentration on the formation of MCs+ in SIMS analysis
Authors: Marie Y. , Gao Y. , Saldi F. , Migeon H. N. 
Published: May 2005

AbstractThis study, investigates the influence of the Cs concentration on the formation of MCs+ions (SiCs+ and Cs2+) in a Si wafer. The Cs concentration was varied by:

Studying the surface transition period in a Si wafer under Cs+ bombardment.
Profiling a Cs‐implanted Si sample.
Investigating different Cs+ bombarding conditions which generate different Cs concentrations in silicon under a steady‐state regime.
The results support the recombination model for the formation of the MCs+ ions. From this model, a quantitative evaluation of the ionization probability of Cs0 was obtained.
Generalization of the tougaard method for inelastic‐background estimation in electron spectroscopy: Incorporation of a depth‐dependent inelastic mean free path
Authors: Graat Peter C. J. , Somers Marcel A. J. , Böttger Amarante 
Published: May 2005

AbstractA generalization of the Tougaard method for subtraction of the background of inelastically scattered electrons from an electron‐energy spectrum is presented. Firstly, a depth dependence of the inelastic mean free path is introduced, which enables the analysis of electron‐energy spectra from elements in inhomogeneous samples. The incorporation of the depth dependence of the inelastic mean free path also provides an equation for the calculation of peak intensities of electron‐energy spectra from elements in inhomogeneous samples and the possibility of estimating the effect of elastic scattering of signal electrons. Secondly, it is shown that the Tougaard method allows the direct calculation of the background of inelastically scattered electrons from a known primary excitation spectrum for an arbitrary in‐depth distribution of electron emitters. The validity of these generalizations is demon‐strated for the case of an XPS model spectrum originating from a substrate covered with an overlayer, by comparing the results obtained in the present study with those reported previously.
Surface studies of the enhanced adsorption of sodium ions onto oxidized surfaces in acetone‐containing aqueous solutions
Authors: Wang Tiejun , Sherwood Peter M. A. 
Published: May 2005

AbstractThe adsorption behavior of sodium ions onto oxidized surfaces was studied with x‐ray photoelectron spectroscopy (XPS). We studied the adsorption of sodium ions onto oxidized surfaces by exposing the surfaces to aqueous neutral and acidic solutions of sodium ions with and without the presence of a high concentration of acetone. The oxidized surfaces chosen were carbon‐fiber surfaces electrochemically oxidized in ammonium carbonate solution, and oxidized aluminum and copper surfaces. No adsorption of sodium ions was found when the oxidized surfaces were exposed to aqueous solutions of sodium ions with no acetone present, but substantial adsorption was seen when neutral aqueous solutions of sodium ions were used with a high concentration of acetone present. Adsorbed sodium ions could not be removed by washing in acetone but could be removed by washing in water. When glutaraldehyde was present in the acetone solutions there was evidence for the surface adsorption of glutaraldehyde/acetone condensation products.
Characterization of a surface‐treated Au–Ag–Cu‐based dental metal–ceramic alloy
Authors: Hautaniemi J. A. , Heinonen M. , Juhanoja J. 
Published: May 2005

AbstractThe oxidation of an Au–Ag–Cu‐based dental metal–ceramic alloy was studied by multitechnique analysis. The elemental spatial distribution of the alloy components was measured by energy‐dispersive x‐ray imaging and scanning Auger microscopy and the depth–concentration profiles studied by XPS and Auger depth profiling. The structure of the oxidized layer was analysed by x‐ray diffraction. Special attention was paid to the pretreatment of the oxidized alloy in order to get a suitable oxide structure, which is known to play an essential role in the porcelain/metal interaction. The studied alloy contained several alloying components, such as In, Cu and Zn, to control melting temperature, strength and porcelain adherence. Oxidation of In could be promoted and that of Cu and Zn inhibited. This is of great importance because In2O3 is known to increase porcelain adherence to noble alloys, whereas CuO tends to cause discolouration of porcelain.
XPS sputter depth profiling of the chemical states for SrTiO3/Si interface by O2+ ion beams
Authors: Kim K. J. , Moon D. W. , Nam S. H. , Lee W. J. , Kim H. G. 
Published: May 2005

AbstractBecause the chemical states of the elements in SrTiO3 thin film on Si are reduced by argon ion beam bombardment, it was impossible to sputter depth profile the chemical states of SrTiO3 thin film by argon ion beams. In this paper, it is reported that the undistorted chemical states of Ti and Si at the SrTiO3/Si interface can be determined with oxygen ion beams at the appropriate 70° angle of incidence, with which either metallic Ti is not oxidized or Ti in SrTiO3 is not reduced. Under the sputter depth profiling conditions, the chemical state of Ti at the SrTiO3/Si interface could be successfully characterized and the effects of post‐annealing at high temperature on the chemical state of Ti were studied. A significant number of Ti atoms in the metallic state were observed at the SrTiO3/Si interface without any post‐annealing but all of them were oxidized to the Ti4+ chemical state after 2 h post‐annealing at the temperatures above 600°C under oxygen flow. The dielectric properties of SrTiO3 thin films on Si were well correlated to the oxidation state of Ti and the broadening of the interface SiO2 layer induced by post‐annealing at high temperature.