bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer functional group mobility. 2—Partition of ion pairs between hydrophobic and hydrophilic phases of plasma oxidized polyethylene
Authors: Everhart Dennis S. , Reilley Charles N. 
Published: December 2004

AbstractPlasma modification of polyethylene is modeled most simply as a process generating a two phase polymer system: a thin hydrophilic surface phase and a relatively unperturbed hydrophobic bulk phase. The oxidized surface of polyethylene exposed to a N (PEN) or to an Ar (PEAr) glow discharge plasma contains functional groups of N (i.e., amines) and of O (i.e., alcohols, carbonyls and carboxylic acids) and constitutes an interesting, chemically unique phase of the polymer. Lipophillic protonated alkyl ammonium nitrates, perchlorates and iodides are more soluble in the internal, hydrocarbon phase of the modified polymer and consequently show negligible electron spectroscopy for chemical analysis intensities. On the other hand, the hydrophilic protonated alkyl ammonium phosphates, sulfates and chlorides concentrate in the more polar surface phase and are readily detected by electron spectroscopy for chemical analysis. Electron spectroscopy for chemical analysis of protonated alkyl ammonium chlorides and iodides is complicated by the evolution of HCl and HI, respectively, into the vacuum. Complete protonation of the N functional groups of PEN with H2SO4 is prevented by prior intra polymer reactions of amines with carbonyl and carboxylic acid groups to form less basic imines and amides, respectively. Sodium carboxylate salts are more soluble in the surface hydrophilic phase, whereas tetrabutylammonium carboxylate salts readily partition into the internal hydrophobic phase. The partition of functional groups between the hydrophilic surface phase and the hydrophobic bulk phase will exert a profound influence on their availability for reaction at the polymer surface.
Suppression of metal surface oxidation during laser surface treatments
Authors: Draper Clifton W. , Kaufmann Elton N. , Buene Leif 
Published: December 2004

AbstractInert cover gases (He, Ar and N2) are commonly used to protect optical lenses, suppress plasma formation and inhibit metal surface oxidation during high power laser treatments. In the three examples studied, widely varying degrees of effectiveness have been found. A 20 lb inch−2nozzle gas of Ar is found to be effective in prohibiting oxidation of polycrystalline Ni during surface melting with a continuous CO2laser. A CuAlFe alloy, however, oxidizes significantly under nearly identical conditions. It has been found that the redistribution of Hf, implanted in single crystal Ni and laser surface melted with Q‐switched Nd–YAG laser pulses, is sensitive to whether the laser melting is done in air or with a He cover gas. This, in spite of the fact that the melt time is less than 500 ns. We conclude that the use of an inert gas or very short laser pulses does not necessarily prohibit the gaseous ambient from reacting with metal surfaces during laser treatments.
Depth profiling by SIMS—depth resolution, dynamic range and sensitivity
Authors: Magee C. W. , Honig R. E. 
Published: December 2004

AbstractDepth profiling by secondary ion mass spectrometry is described with emphasis on three important aspects: (1) depth resolution, (2) dynamic range and (3) sensitivity. It is shown how, for samples which do not roughen during sputtering, depth resolution is limited by atomic mixing effects and the flatness of the analyzed area. The dynamic range of depth profiles is shown to be limited by (a) crater edge effects, (b) neutral beam effects and (c) several types of instrumental background. These include mass spectral overlap, residual gas contamination, redeposition and ‘memory’ effects, and detection of unfilterable particles. In the absence of measurable background, sensitivity is shown to be related to analyzed area and depth resolution.
SIMS study of a 55% AlZn alloy coating for corrosion protection of steel wire products
Authors: Van Craen M. , Adams F. , Haemers G. 
Published: December 2004

AbstractSecondary ion mass spectrometry with a Cameca ion microscope was used to study the surface and in‐depth composition of a 55 wt % AlZn coating on steel wire. Several surface contaminants of the coating (C, Na, Mg, F, Cl, K, Ca, Mn and Fe) were identified and the spatial distribution of some of them and of the coating components Al, Si and Zn were obtained. The dendritic–interdendritic structure of the AlZn coating was observed using a secondary ion imaging facility. The distribution at the surface of the coating constituents Na and Cl, C and Al and Mn and Fe were strongly correlated. Quantitative analysis showed that the Mn and Fe surface concentrations were some hundreds and some thousand p.p.m. wt, respectively.
Behaviour of water containing materials in the high vacuum of an X‐ray photoelectron spectrometer
Authors: Hirokawa K. , Danzaki Y. 
Published: December 2004

AbstractIn order to examine the behaviour of water containing materials in the high vacuum of an electron spectrometer, semi‐quantitative XPS measurements of the atomic ratio of O to an element in certain inorganic compounds were carried out. Materials investigated were CuSO4·5H2O, KCr(SO4)2·12H2O, FeC2O4·2H2O, Sn(OH)2, Al(OH)3, Fe(OH)3, Ti(OH)4, Zn(OH)2, Zr(OH)4 and some metals. It can be anticipated from the correlation between the vapour pressure, of water and temperature that water containing materials, which are dehydrated under 400 °C at normal pressure, lose water under a vacuum of about 10−8 Torr. Of course, it became clear that measurements of water containing materials in the high vacuum should be performed very carefully.
The correlation of the auger parameter with refractive index: An XPS study of silicates using Zr Lα radiation
Authors: West R. H. , Castle J. E. 
Published: December 2004

AbstractThe value of using Zr Lα x‐rays as a source for the XPS study of AlSi compounds is proved by their ability to generate strong Al and Si is and KLL Auger peaks and with sufficient resolution for peak energies to be determined accurately. A study of the resultant Al and Si Auger parameters has been made for some 30 silicates and comparison with refractive index data allows the Auger parameters to be scaled directly with the polarization energy of the surrounding O ions. The O polarizability dominates the bulk polarizability in silicates and its magnitude is controlled by its site co‐ordination number and the electronegativity of charge‐balancing cations in the structure. Oxygen ions surrounding Si and tetrahedral Al sites have highly variable, but strongly interdependent, polarizabilities; however, the O polarizability is almost invariant around octahedral Al sites. The correlation of relaxation energy in a silicate lattice with polarizability is finally compared with the London force interaction between molecules.
Analysis of polymer surfaces by SIMS 1. An investigation of practical problems
Authors: Briggs D. , Wootton A. B. 
Published: December 2004

AbstractSecondary ion mass spectrometry has the potential for high spatial resolution surface analysis of polymers via fingerprint mass spectra and the use of a focused ion beam. Several problems stand in the way of realizing this potential, namely: (a) the expected high rate of ion beam damage, (b) the need for charge neutralization leading to (c) the uncertainty of surface potential and (d) the possibility of electron stimulated desorption of secondary ions. The importance of these effects have been studied using a model short chain hydrocarbon and films of polystyrene and polytetrafluoroethylene.
Inelastic electron tunneling spectroscopic study of the silane coupling agents: 1—Aminophenyltrimethoxysilane adsorbed on plasma grown aluminum oxide and effects of high humidity
Authors: Furukawa T. , Eib N. K. , Mittal K. L. , Anderson H. R. 
Published: December 2004

AbstractThe adsorption mechanism of aminophenyltrimethoxysilane adsorbed from the vapor on plasma grown aluminum oxide and effects of high humidity on the adsorbed silane were studied by inelastic electron tunneling spectroscopy (IETS). The IETS spectrum of aminophenyltrimethoxysilane contains the bands due to phenyl rings, methyl groups and amino groups. The NH2 deformation mode is shifted to lower frequencies, which may imply that the silane is chemisorbed through the amino group. By exposing the sample to water vapor, the methoxy group hydrolizes and the resultant methanol is removed from the varrier region indicated by a significant loss of intensity of the CH3 stretching and deformation modes. A loss of intensity of the NH2 deformation mode was also observed after the exposure.
On the influence of crater edges and neutral beam component on impurity profiles from raster scanning SIMS
Authors: Vandervorst W. , Maes H. E. , De Keersmaecker R. 
Published: December 2004

AbstractA mathematical evaluation is presented for the beam raster scanning mode of depth profiling with SIMS, combined with electronic gating of the detection system. A computer program was developed in which a former treatment of the influence of the crater edges is extended to arbitrary impurity profiles and which also accounts for neutral particles in the primary beam. It is shown that these neutrals have a dramatic effect on the obtained dynamic range and that the commonly used background subtraction technique does not necessarily lead to the correct profile. The simulation including neutrals shows good agreement with an experimentally measured profile. Finally, the influence of the crater edges and the choice of an appropriate structure for measuring depth resolution and outdiffusion are discussed.
On the influence of crater geometry on depth resolution of AES and XPS profiles of tantalum oxide films
Authors: Mathieu H. J. , Landolt D. 
Published: December 2004

AbstractThe influence of crater geometry on depth resolution in AES and XPS depth profile analysis was studied using modern apparatus with double cylindrical mirror analyser and a differentially‐pumped ion raster gun. Anodic Ta2O5 films with thicknesses between 3–100 nm served as a model system. Ion and electron beam raster size, beam alignment, ion energy and film thickness were varied. Results show that optimalization of geometrical factors is important for obtaining good depth resolution. Under favourable conditions, depth resolution characterized by the measured apparent width of the metal–oxide interface was found to be as low as 1.5 nm for AES and 2.3 nm for XPS, respectively. Because of impurity adsorption better depth resolution is obtained if analysis and sputtering are carried out simultaneously rather than alternatively.
Quantitative determination of the kinetics of the reaction of NiO and Al2O3 to NiAl2O4 by Rutherford backscattering
Authors: De Roos G. , Fluit J. M. , Velthuizen R. P. , De Wit J. H. W. , Geus J. W. 
Published: December 2004

AbstractA quantitative evaluation of RBS data resulted in data for the parabolic reaction rate constants for the reaction between Al2O3 and NiO at temperatures from 960°C up to 1105°C. The activation energy and the preexponential factor were in good agreement with literature data. The experimental data of this work also permitted a detailed description of reaction mechanisms on a microscopic level. The reaction between Al2O3 and NiO starts with penetration of Al3+ ions along the grain boundaries of NiO, followed by counter‐diffusion of Ni2+ ions. A thin spinel layer (NiAl2O4) is formed at the Al2O3/NiO interface, after a relatively short nucleation period. The reaction then proceeds, both by lateral and perpendicular diffusion. In an appendix, the detailed evaluation procedure of the spectra was described.
Monochromatized Ag Lα X‐rays as a source for higher energy XPS
Authors: Yates K. , West R. H. 
Published: December 2004

AbstractMonochromatization of Ag Lα X‐rays is achieved by fitting an Ag anode to a conventional Al Kα monochromator. Many new XPS lines are generated by this high energy source including the 1s and KLL Auger series from Al to Cl. Chemical state determination by means of the Auger parameter for these elements is greatly assisted by the reduced X–ray linewidth after monochromatization. Three glass fibre samples with different surface pre‐treatments were studied to show that chemical state information could be extracted from even these complex, rough and insulating surfaces by using this novel X‐ray source.
Laser microprobe mass analysis (LAMMA) and adsorption study of aliphatic alkylammonium ions and alkylamines on asbestos fibre surfaces
Authors: De Waele J. K. , Verhaert I. , Vansant E. F. , Adams F. C. 
Published: December 2004

AbstractThe adsorption–desorption behaviour of aliphatic alkylamines for asbestos was studied. A high affinity and strong adsorption characteristics, controlled by Van der Waals interaction and steric hindrance were obtained. For the RnNH4−nCl (1 ⩽ n ⩽ 4) doped asbestos fibres, the laser microprobe mass analysis (LAMMA) technique was used to analyse selectively the individual asbestos surface loadings. Only for quaternary (and tertiary at higher concentrations) ammonium products, could a semi‐quantitative picture of the organic asbestos surface covering be observed.
The reactive behaviour of the BCL3/H2/steel system
Authors: Than E. , Luthardt M. , Marx G. , Finster J. , Meisel A. 
Published: December 2004

AbstractFor the description of reactions between solids and gases it is important to investigate the compositional changes in the surface of the solid as a function of temperature and reaction time. Conventional methods of surface analysis cannot be applied in such investigations under atmospheric pressure. We have used the techniques of thermal analysis by emission spectrography (TESG) and of X‐ray photoelectron spectroscopy (ESCA). Work with aggressive gases under atmospheric pressure was done in a special reactor, connected by a vacuum‐lock directly to the ESCA spectrometer. Thus we have been able to establish characteristic reaction temperatures in the BCl3/H2/steel system and to assign them to certain surface changes. From that a model for the initial phase of the formation of the boride layer on a plain carbon steel has been derived.
XPS surface and bulk studies of heat treated palladium in the presence of hydrogen at 150°C
Authors: Moddeman W. E. , Bowling W. C. , Carter D. C. , Grove D. R. 
Published: December 2004

AbstractPalladium metal powders used for hydrogen isotope pumping were studied for their bulk and surface chemistry changes during cleaning with hydrogen gas at 150°C. Cleaning is necessary to promote rapid hydriding and dehydriding and to prevent contaminant ingrowth in the process gas during use. These studies show that heating the powders in vacuum at moderate temperatures (150°C) in a reducing environment removes surface oxide, leaves a predominately palladium metal surface which presents no significant barrier to hydrogen absorption or desorption, and shows no loss in surface area and pourability. A surface model of PdO is given and XPS results show that the water‐forming reaction is the mode of PdO reduction. Thermodynamic data are discussed which support the above results.
Ignition mechanism of the titanium–boron pyrotechnic mixture
Authors: Burke A. R. , Brown C. R. , Bowling W. C. , Glaub J. E. , Kapsch D. , Love C. M. , Whitaker R. B. , Moddeman W. E. 
Published: December 2004

AbstractTitanium–boron pyrotechnic reactions are essentially gasless, are very exothermic, and are known to initiate only at extremely high temperatures. The reactants are stable in normal laboratory environments and require no special sample handling, such as inert storage. These factors make the titanium–boron mixture ideal for one‐shot thermal heat source applications. Mound has been investigating energetic material ignition properties for a number of years. Pyrotechnic mixtures of TiHx/KClO4 have revealed that the surface composition of the titanium fuel was TiO2 and its presence on the fuel's surface controls the TiHx + KClO4 reaction. In the present study the surface chemistry of titanium and of boron have been examined before ignition. To understand the effect of temperature on the reactants and the mixture, titanium powder, boron powder, and blends were analyzed at ambient and elevated temperatures. XPS, TG and DTA results presented will show that the oxide on boron is the controlling factor in the ignition mechanism of the titanium–boron pyrotechnic reaction.
Morphological and chemical changes in palladium alloy gauzes used for platinum recovery in high‐pressure ammonia oxidation plants
Authors: Fierro J. L. G. , Palacios J. M. , Tomás F. 
Published: December 2004

AbstractScanning electron microscopy (SEM) combined with energy dispersive x‐ray analysis (EDX) and x‐ray photoelectron spectroscopy (XPS) have been used to study platinum recovery by catchment on palladium alloy gauzes placed at the outlet of high‐pressure plants for ammonia oxidation. It has been found that Pt evaporated from the Pt–Rh catalyst gauzes is efficiently recovered by a pack of Pd gauzes situated downstream. During this process important geometrical, morphological and chemical changes take place. In general, the wire diameter increase depends on the gauze position in the pack and also on the initial wire diameter. This diameter increase, due to Pt alloying, is accompanied by deep recrystallization and faceting. Chemical analysis by both EDX and XPS revealed that the Pt/Pd ratios depend markedly on the position in the catchment pack, and also on the orientation with respect to the stream (front or back face). In addition, nodular Rh2O3particles randomly distributed over the Pd alloy surface have been observed. An explanation for these features is given.
Damage and recovery by electron and ion beam irradiation during AES analysis of silicon oxynitrides
Authors: Bender H. , Chen W. D. 
Published: December 2004

AbstractDamage and recovery induced by electron and ion beam irradiation during AES analysis of silicon nitride and oxynitrides are discussed. The results show that after prolonged electron beam irradiation, a damage peak is induced in the Si LVV spectrum. The initial incubation time decreases for higher electron current densities and for higher O/N rations. The electron beam‐induced damage is irreversible. The silicon nitride and oxynitrides are very susceptible to damage by energetic ion impact. However, this damage is reversible: the surface can be recovered by irradiation with an electron beam in the ultra‐high vacuum system when the electron current density is kept low. The damage recovery is related to the irradiation time, the current density and the beam energy, as well as to the preparation method of the layers. The degree of damage and recovery are characterized by the fraction of ‘covalent’ silicon and silicon nitride obtained from factor analysis of the Si LVV spectrum. The mechanism of the damage and recovery will be discussed.
The effect of thin titanium oxide layers on the wettability of thin‐film nickel metallization
Authors: Thomas Iii J. H. , , Hitch T. T. 
Published: December 2004

AbstractMonolayer thickness TiO2contamination layers are shown to be detrimental to reflow soldering of thin‐film nickel, which is a part of the Al‐Ti‐Ni metallization system used in backplane metallization of silicon chips. Measurements based on real‐time flow of Pb‐Sn(10 wt.%)‐Ag(2 wt%) alloy solder show that the presence of approximately one monolayer of TiO2plus NiO on Ni raises the temperature at which solder begins to flow in the forming gas (10% H2) by 100°C over that of a clean NiO native oxide layer on Ni. Surface chemistry was determined using x‐ray photoelectron spectroscopy and Auger electron spectroscopy. Solder pool area measurements as a function of solder temperature were used to determine qualitatively the wettability of a surface. Poorly wetting surfaces show a negative slope. In this study, the slope was negative at equivalent Ti coverages, as determined by Rutherford back‐scattering analysis, of 0.65 nm or greater. The wettability of the surface appears to be controlled by TiO2at 0.65 nm or above and may be related to the ability of the forming gas to reduce the surface oxide sufficiently at the soldering temperature to permit flow. Therefore, small amounts of Ti that may diffuse through the nickel layer of the three‐metal thin‐film metallization system can have significant effects on the wettability of the Ni surface.
Effects of SO2 deposition on painted steel surfaces
Authors: Davis G. D. , Shaw B. A. , Arah C. O. , Fritz T. L. , Moshier W. C. , Simpson T. C. , Moran P. J. , Zankel K. L. 
Published: December 2004

AbstractThe effects of 1 ppm SO2 with high humidity on alkyd‐painted steel was investigated using x‐ray photoelectron spectroscopy (XPS) and adhesion tensile tests. The SO2 caused a spotted discoloration on the specimens on which dew is allowed to dry and accelerated the loss of adhesion between the primer and the steel. The brown spots are characterized by a high S content and form in areas where the condensed dew becomes more concentrated in H2SO3 or H2SO4 as it evaporates. Specimens not exposed to dew also have high S concentration on the surface, but do not discolor. High humidity alone caused a loss of adhesion at the primer–metal interface, but SO2 increased the rate of this de‐adhesion. Such a loss of adhesion decreases the protection provided by the paint system and the presence of Fe on both sides of some failures indicated that the substrate was beginning to corrode.
Depth profiles of Ag/Si(111) thin‐film interface regions
Authors: Chambers G. P. , Sartwell B. D. 
Published: December 2004

AbstractThe metal/semiconductor interface region of in situ deposited Ag thin films prepared on a Si(111) substrate has been investigated using AES sputter depth profiling in conjunction with proton‐induced x‐ray emission (PIXE). Interface regions have been modeled with the interface analysis program LOGIT, developed at the National Institute of Standards and Technology (NIST). Values for the parameters obtained from this model indicate that the rate of ion beam sputtering through samples prepared without simultaneous low‐energy ion activation tended to be noticeably greater than the rate of sputtering through samples prepared with simultaneous ion activation. Further, we found that one effect of the ion beam is temporarily to shift the fractional Ag surface coverage to higher values. The likely mechanism for this shift is sputter redeposition by the ion beam of Ag atoms from large nucleated Ag islands, transporting them to open areas between islands. These results support conclusions from an earlier study, which found that the effect of low‐energy simultaneous ion beam activation during thin‐film deposition was to shift the mode of growth of Ag on an Si(111) substrate from an SK (layer‐plus‐island) to an FM (layer) growth mode, to a degree dependent on the conditions of simultaneous ion co‐bombardment.