bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling the Effects of Evolving Redox Conditions on the Corrosion of Copper Containers
Authors: King F. , LeNeveu D. M. , Jobe D. J.
Published: March 2011

The corrosive environment around the containers in a Canadian nuclear fuel waste disposal vault will change over time from “warm and oxidizing” to “cool and anoxic”. As the conditions change, so too will the corrosion behaviour of the containers. For copper containers, uniform corrosion and, possibly, pitting will occur during the initial aggressive phase, to be replaced by slow uniform corrosion during the long-term anoxic period.

The corrosion behaviour of copper has been studied over a range of conditions representing all phases in the evolution of the vault environment. The results of these studies are summarized and used to illustrate how a model can be developed to predict the corrosion behaviour and container lifetimes over long periods of time. Lifetimes in excess of 106 a are predicted for 25-mm-thick. copper containers under Canadian disposal conditions.
Perspectives on Performance Assessment and High-Level Waste Glass in a Geologic Repository
Authors: Mcgrail B.P. , Engel D.W.
Published: March 2011

The design and analysis of waste package and engineered systems for geologic disposal of radioactive wastes are being conducted in most countries with so-called performance assessment models and associated computer codes that solve the governing equations. The models range in complexity from simple 1-D analytical solutions to multidimensional, multicomponent reactive transport models implemented in large computer codes. Borosilicate waste glass is certainly the most studied and probably best understood waste form that has been developed for encapsulating high-level waste. Reasonably good models are available that describe the reaction kinetics and transformation of the glass into a paragenetic sequence of more stable secondary phases. Given the broad range of computational tools and extensive database on glass/water reactions that is available, it is surprising that little progress has been made to link these models and data in a comprehensive performance assessment of waste glass in a repository setting. In this paper, we will explore reasons why this linkage has not been developed, give several examples illustrating the importance of doing so, and illustrate an approach to accomplish such a linkage.
Flexural Strength and Fracture Properties of a Fly Ash Blended Cement
Authors: Chanda S. , Bailey J. E.
Published: March 2011

The flexural strength, fracture toughness and Young's Modulus of an ordinary Portland cement plus 25 wt% fly ash paste (FACP) were compared with those of a control paste (HCP) at times ranging from one day to one year. At comparatively early times these properties develop more slowly in FACP. However, at comparatively late ages, e.g. ten months, FACP showed improvements over HCP for all of these properties. A complicating factor is that for both FACP and HCP, the flexural strength and toughness show maxima and the “crossover” times for the various properties differ. This paper analyses these results in terms of the observed fracture mechanism for HCP by taking into account the changes brought about in the microstructure of FACP, due to the incorporation of fly ash.
Properties and Potential Uses of the Products Resulting from Bed Combustion of Coal Washery Wastes the Fluidised
Authors: Montgomery Denis G.
Published: March 2011

A fluidised bed combustion (FBC) process has been developed to a stage that both coarse rejects and tailings from coal washery plants may be successfully combusted. During the combustion process excess heat is produced, and the products from the process, spent rejects and primary and secondary cyclone fines, are reduced in volume compared to the input material. Results of preliminary investigations into the properties of the spent rejects and cyclone fines are reported. A program has been initiated to investigate and evaluate the potential uses of the FBC process, including the use of the products in stabilised and unstabilised forms in road construction, as a material suitable for the construction of embankments, and in lean concrete mixes either as an aggregate or as a pozzolan.The characteristics of the FBC products are compared, where appropriate, with those of the unburnt coal washery wastes.
Utilization of Fly Ash in Roadbed Stabilization: Some Examples of Western U.S. Experience
Authors: Manz Oscar E. , Manz Bradley A.
Published: March 2011

In contrast with pozzolanic bituminous fly ashes, the western American lignite and subbituminous fly ashes are both pozzolanic and cementitious. During the last three years, there has been much research and actual use of western ash alone and with lime or cement for roadbed stabilization. In contrast with lime stabilization which only applies to clay, the western ashes can be used to stabilize clay as well as silty and granular soils. Fly ash is moving from the experimental to standard alternative for pavement in many states. Some examples of western U.S. experience will be presented.
Utilization of Fly Ash in Oil and Gas Well Cementing Applications
Authors: Sarkar Asok K.
Published: March 2011

During cementing operations, the hydrostatic pressure of the cement slurry column is utilized to control the reservoir pressure. However, when the well extends through weak formations, it is often necessary to lighten the hydrostatic pressure of the slurry by lowering the density to avoid hydraulically fracturing the reservoir rock. Densities of cement slurries can be lowered by adding pozzolanic lightweight additives such as fly ash. Fly ashes have found utility in numerous oil and gas well cementing applications, namely: 1) fly ash can be dry-blended with regular Portland cements or hydrated lime for use in primary cementing; 2) lightweight cement compositions can be formulated by adding lime and finely ground quartz to fly ash/cement mixtures; and 3) an ultralight-weight pozzolanic microsphere cement, with densities as low as 0.96–1.64 g/cm3, can be formulated by blending Portland cements with hollow microspheres isolated from fly ash. This paper discusses the physical and chemical properties of each of these cement slurries, along with their relative advantages and disadvantages. Areas of future research are also discussed.
Comparative Bconomics of Several Alternatives for Bulk Utilization of Fly Ash and Coal Gsification Ash
Authors: Severson D. E. , Manz O. E. , Mitchell N. J.
Published: March 2011

Abstrct

Fly ash and gasification ash have been evaluated economically for the following uses: partial replacement of Portland cement; mineral wool; blended cement; Sulfurcrete®, high flexural strength ceramic products; ash to upgrade roads; glazed ceramic wall tile; and unglazed floor tile. The ash evaluated is a high-calcium, high-sodium material derived from the Beulah-Zap lignite mined in the Beulah region of North Dakota. Of the uses examined, concrete replacement provided an 8.0% cost saving, blended cement 37.3%, high flexural strength ceramics 52.8%, ash in road construction 44.4%, and wall tile 5.2%. Mineral wool had no replacement savings calculated because blast furnace slag is not available locally to provide a consistent basis. Sulfurcrete® did not provide a cost saving over concrete but its use life and properties are sufficiently different from those of concrete to justify use in some applications, provided that the raw materials are readily available.
Transmitted and Reflected Visible Light Microscopy of Two Bituminous Fly Ashes
Authors: Biggs Donald L. , Bruns Joseph J.
Published: March 2011

Fly ashes of high magnetic content taken from two midwestern power plants were examined to determine the mineralogy of the magnetic and nonmagnetic fractions. Fly ash spheres from the magnetic fraction are predominantly composed of ferrite spinel, hematite and silicate glass. The hematite appears to be a replacement product of the original ferrite spinel. Nonmagnetic phases include mullite, lime, small amounts of hematite and silicate glass. Quartz morphology indicates that it did not fuse in the furnace. Mullite and lime have morphologies indicative of crystallization in the furnace. Hematite is bonded to the nonmagnetic particles or as a complete replacement of ferrite spinel spheres.
Mobility of Organic and Inorganic Constituents from Energy and Combustion-Related Wastes Under Codisposal Conditions
Authors: Maskarinec M. P. , Francis C. W. , Goyert J. C.
Published: March 2011

The criteria for determining toxicity of a solid waste under the Resource Conservation and Recovery Act (RCRA) are the levels of NIPOW contaminants as determined using the extraction procedure (EPA-EP). This procedure is predicated on a scenario of disposal of the solid waste in a municipal landfill, resulting in contact with an acidic leaching medium. The scenario includes a 95/5 municipal waste/industrial waste ratio. The experimental definition of the leaching rates of various contaminants under the conditions of this scenario is the object of this work.

The experimental design included the use of large scale lysimeters (1.8 M in diameter × 3.6 M height) packed with 1.5 metric tons of municipal waste. A flow rate of -6.5 1/day of distilled water was added to the lysimeters for the generation of municipal waste leachate (MWL). The MWL was used to leach a variety of industrial wastes, including resource recovery ashes, an API separator sludge/incinerator ash mixture, and a coking plant wastewater treatment sludge. The resulting leachates were analyzed for both inorganic and organic constituents.

Inorganic constituents showed two distinct types of leaching behavior. Freely soluble elements (B, Na, Ca, etc.) gave leaching curves which showed exponential declines. Acid-soluble elements (Ni, Zn) eluted as “peaks” as the pH of the leachate decreased. Organic constituents gave leaching curves which were dependent on solubility: either an exponential decline (freely soluble compounds) or a relatively flat curve at or near the solubility limit. The availability of this data base has allowed the development of a laboratory extraction procedure for the prediction of contaminant migration in municipal landfills.
Technical Review of the Energy Authority Coal Waste Artificial Reef Program (C-WARP)
Authors: Hornibrook C. A. , Parker J. H.
Published: March 2011

The objective of the Coal Waste Artificial Reef Program (C-WARP) is to explore the technical feasibility and environmental effects of ocean disposal of stabilized fly ash and flue gas desulfurization scrubber sludge from power plants. This demonstration program has involved the construction of an artificial reef in the Atlantic Ocean off Long Island, New York using 15,000 blocks of these stabilized coal waste materials.

In determinine the environmental acceptability of using stabilized copl waste blocks to build artificial reefs in the ocean, the two key considerations are whether the blocks will maintain their structural integrity, and whether the blocks will be a source of potentially toxic elements to affect the biological community. Analysis of the chemical composition of the blocks and an understanding of the processes occurring in them is necessary to address these questions. Therefore, this paper will focus on changes in chemical composition of blocks (e.g., Ca flux, Mg enrichment, and surface layer elemental concentrations) and compatibility of the blocks in terms of the physical and biological data collected during three years of monitoring.
Electrokinetic Phenomena and Surface Characteristics of Fly Ash Particles
Authors: Malek R. I. A. , Roy D. M.
Published: March 2011

The zeta-potentials of two fly ashes were studied (high-calcium and low-calcium). It was found that they possess a point of charge reversal at pH = 10.5 to 12. The point of zero charge (low-calcium fly ash) was found to be at pH = 5. Furthermore, it shifted to more acidic values after the fly ash is aged in several calcium-containing solutions. The surficial changes that could happen when mixing fly ashes with cement and concrete were further evaluated by aging fly ashes in different solutions: Ca(OH)2, CaSO4·2H2O, NaOH and water solutions. Information from analyses for different ionic species in the solutions and characterization of the solid residues (XRD and SEM) was used in tentative explanations for the different behavior of the two types of fly ash in cementitious mixtures and concrete.
Effects of Fly Ash and Superplasticizers on the Rheology of Cement Slurries
Authors: White Elizabeth L. , Lenkei Maria , Roy Della M. , Tamas Ferenc D.
Published: March 2011

Cementitious slurries composed of an oil well cement, a high calcium fly ash, a low calcium fly ash, and three commercially available superplasticizers (two different sulfonated naphthalene formaldehyde condensates and a sulfonated melamine formaldehyde condensate)were mixed to contrast the two fly ashes and to determine the effectiveness of each of the superplasticizing agents. Most commercial superplasticizers and cements are relatively expansive; therefore a partial substitution by fly ash and other by-products represents a substantial savings in both quantity of chemical admixture required and energy consumption for the manufacture of cement. In the cement/fly ash mixtures of 100/0, 90/10, 60/40, 40/60, and 10/90, with both high calcium fly ash and low calcium fly ash, the mixture containing the low calcium fly ash was consistently less workable. The rheological properties of the high vs. low calcium fly ash mixtures were controlled by the differences in fly ash particle size and the presence of irregular large particles, rather than by the differences in chemistry between the two. The low calcium fly ash was the coarser material.
Progress and Prospects of Materials Characterization at Subnanometer Spatial Resolution using Finely Focussed Electron Beams
Authors: Isaacson Michael
Published: March 2011

The prospects of microanalysis using 0.5 nm diameter electron beams are reviewed. This paper will discuss the various characterization possibilities with emphasis on incoherent imaging, energy loss spectroscopy and convergent probe diffraction. Some examples indicating characterization at a 0.5 nm lateral spatial resolution scale will be presented and we will conclude with a discussion of the limits of nanometer characterization.
Transmission Electron Microscope Investigation of Sputtered Co-Pt Thin Films
Authors: Alexopoulos P. , Geiss R. H. , Schlenker M.
Published: March 2011

Thin films of Co-10 at% Pt, ranging from 15 to 90 nm in thickness, have been DC-sputtered at various temperatures on to carbon-coated mica, carbon substrates on copper grids, or (001) silicon single crystals under 3 μm pressure of Ar, using targets of the alloy in the hexagonal phase, at growth rates of 9 nm/min. The samples were investigated by TEM, using bright-and dark-field imaging, lattice imaging, selected area diffraction and both Fresnel and focussed Lorentz modes. The primary structure of the films was found to be hexagonal, with a = 0.255 nm and c = 0.414 nm. For the samples sputtered at room temperature, the grain sizes were on the order of 0.μm on carbon-coated mica and carbon-substrate grids, and approximately an order of magnitude smaller on silicon substrates. Heavy streaking along the [001] of the hexagonal matrix was observed on diffraction patterns for grains having the [001] parallel to the surface; this streaking was found to be associated with the presence of a high density of faults parallel to the (001). In films sputtered on to carbon-coated mica at 225 °C, where a substantial reduction of the coercivity is observed, the overwhelming majority of the grains had the (001) basal plane parallel to the surface. Lorentz microscopy showed the magnetic domain structure in films grown on silicon to be markedly different from those grown on the carbon substrates, and further changes occurred for the films grown at elevated temperatures.
Refractory Metals Growth on MBE GaAs
Authors: Bloch J. , Heiblum M.
Published: March 2011

Nolybenum and tungsten metals have been grown on an MBE grown (100)GaAs at various substrate temperatures. RHEED technique was used in situ to analyse the crystalline structure and the growth mechanism of the mechanism of the thin metal films. It was found that Mo epilayers can be grown on the (100) GaAs at temperatures between 150–400°C. The epitaxal arrangement is (111)Mo || (100)GaAs with [011]Mo || [011] GaAs. Tungsten films are not growing epitaxially under similar experimental conditions.
Auger Sputter Depth Profiling Applied to Advanced Semiconductor Device Structures
Authors: Skinner D. K. , Hill C. , Jones M. W.
Published: March 2011

The continuing miniaturisation of modern semiconductor devices is placing new demands on the spatial resolution of many existing assessment techniques. With device structures reduced to nm dimensions the need to optimise conditions for high resolution in-depth profiling is essential for accurate characterisation. In this paper we present Auger profiles of two micro-electronic structures and consider the choice of ion beam parameters necessary to minimise ion beam induced distortion. In VLSI (Very Large Scale Integration) technology where high dopant concentrations are ion implanted into shallow layer structures, Auger profiling can be used to establish dopant distributions accurately in the peak regions of the high dose implant. This information is shown to provide data for process modelling programmes.

Also presented are profiles of MOCVD (Metal Organic Chemical Vapour Deposition) grown GaAlAs/GaAs superlattices with 70 Å repeat structures. Interface width measurements are of particular importance in this case where sharp interfaces are a pre-requisite for good device performance. These structures have been found to be very vulnerable to enhanced atomic mixing, a consequence of the small mass of the Al atom. The Al content of the GaAlAs determining the obtainable in-depth resolution.
Electron Spectroscopic Studies of Substoichiometric Tantalum Carbide
Authors: Gruzalski G. R. , Zehner D. M. , Ownby G. W.
Published: March 2011

XPS was used to determine core-level binding energies and valence-band structure for TaCx over the range 0.5 ≲ × ≲ 1.0. As x decreased, the carbonls binding energy (BE) changed very little, the carbon-2s BE shifted toward the Fermi level, the position of the p-d valence-band peak shifted toward the Fermi level more, and the tantalum-4d and -4f BE's shifted toward the Fermi level even more, about 0.16 eV for a change in × of 0.1. In addition, the valence-band spectra exhibited structure between about 1 and 2 eV BE, and this structure increased as x decreased. These observations are explicable in terms of charge transfer and the formation of occupied defect states associated with carbon vacancies.
Experimental Investigation of GaAs Surface Oxidation
Authors: Matteson S. , Bowling R. A.
Published: March 2011

Experimental observations of the surface oxide chemistry of GaAs are reported for various commonly used chemical surface preparations. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and ellipsometry were employed to obtain information regarding the stoichiometry, depth distribution, and oxide growth kinetics of thin surface oxides. Previous observations of the segregation in depth of Ga and As oxides are corroborated. Arsenic oxides tend to be found near the surface while Ga2O3 is found near the GaAs-oxide interface. The presence of elemental As was frequently detected at this interface, as well. Surfaces essentially free from oxide are shown to be produced by certain chemical treatments, and the state of the surface in the solution is inferred. It is shown that the GaAs surface oxide stoichiometry can undergo several changes in a short time when exposed to water and air. In addition, the characterization of the oxidation of GaAs by ozone in the presence of intense ultraviolet illumination is reported. The oxide primarily consists of Ga2O3 and exhibits an interesting growth kinetics: the thickness of the oxide proceeds at first linearly, then logarithmically, then parabolically. This behavior is explained in terms of various mechanisms which are dominant at different thicknesses of oxide.
On the use of Secondary Ion Mass Spectrometry in Semiconductor Device Materials and Process Development
Authors: Magee Charles W. , Botnick Ephraim M.
Published: March 2011

This paper describes how secondary ion mass spectrometry can be used effectively in semiconductor device materials and process development. A short overview of the experimental technique is given followed by applications in the following areas:

1) Basic research

2) New Process Development

3) Trouble-shooting current processing

4) Analysis of competitor's devices.
Sims Characterization of Thin Thermal Oxide Layers on Polycrystalline Aluminium
Authors: Degreve F. , Lang J. M.
Published: March 2011

Thermal oxide layers of different thickness (T = 3.5–18 am) covering polycrystalline aluminium sheets were investigated by dynamic SIMS in an ion microscope. Depth profiles of major elements (Al, O), segregated impurities in the oxide layer (Li, Na, Be, Mg) and implanted 18O were recorded for different operating conditions : energy, incident angle, chemical (Ar+ or O2+) and isotopic (16O2+ or 18O2+) nature of the primary beam and oxygen jet to saturate the surface.

The main results are:

- the shape of the depth profiles is very sensitive to operating conditions : the best depth resolution is obtained at low energy (2.5 keV) and the minimal distorsion with an O2 jet, even under O2+ bombardment. Deconvolution would be necessary to deduce the true depth profiles.

- a tremendous enrichment (103 – 104) of the oxide to the Al bulk is observed for Li, Na, Be and Mg via an efficient diffusion mechanism during heat 425°C. Their depth distribution within the oxide layer is heterogenous with surface enrichment for Li and Na and sub-layer (towards the oxide/metal interface) for Be lateral distribution below the interface is also heterogeneous e.g. at the grain boundaries for Be and Na.

- the depth profile of implanted 18O+ versus operating conditions and oxide thickness gives direct information on the dynamic oxidation of Al induced by O2+ sputtering in the first 20 nm.
In Situ Ion Implantation for Quantitative SIMS Analysis
Authors: Lareau Richard T. , Williams Peter
Published: March 2011

The primary ion column of a secondary ion mass spectrometer (Cameca IMS 3f) has been used as an ion implanter to prepare calibrated standards, In situ for quantitative SIMS analysis, with an accuracy better than 10%. The technique has been used to determine oxygen concentrations in contaminated TiSi2 films by implanting a reference level of 18O into a portion of the film.
Microfocussed Ion Beams for Surface Analysis and Depth Profiling
Authors: Kingham David R , Vohralik P , Fathers D , Waugh A R , Bayly A R
Published: March 2011

SIMS microprobe analysis using a liquid metal ion source (LMIS) for the primary ion probe can give fast, sub-micron resolution, chemical imaging of matrix and trace elements. The high brightness and small source size of the LMIS is vital for this high performance. Using a new 30kV gallium ion micro-probe a spatial resolution of 50nm can be achieved with a probe current density in excess of 1 A/cm2. A newly configured SIMS instrument is described which incorporates either a gallium or caesium ion probe as well as a duoplasmatron for ultimate sensitivity and depth profiling performance. For small area, high spatial resolution, depth profiling a raster-scanned ion micro-probe is ideal. A quadrupole mass spectrometer gives a mass range of 1–800 or 2–1200 amu. Examples are presented of up to 50nm resolution SIMS imaging with both positive and negative secondary ions and up to 50nm resolution ion induced secondary electron imaging of a wide variety of samples including superconductors, steels, alloy fractures, optical fibres, integrated circuits, catalysts, polymers and biological specimens. The recent addition of framestore to the system has enhanced the imaging capability, allowing secondary electron and several different secondary ion images of a sample to be overlaid in contrasting colours.
Some Applications of SIMS and SSMS in Materials Characterization
Authors: Verlinden J. , Vlaeminck R. , Adams F. , Gijbels R.
Published: March 2011

Some applications of spark source mass spectrometry are given showing that this technique, often considered as suitable for bulk analysis only, can also be used for the determination of impurities in thin layers and for in-depth profiling in rather thick samples.

Secondary ion mass spectrometry, in addition to its applications in surface- and in-depth analysis, can successfully be applied to quantitative analysis when using the matrix ion species ratio as an environment sensitive indicator, or when using the isotope dilution method.
Hydrogenation during Thermal Nitridation of SiO2
Authors: Kuiper A. E. T. , Habraken F. H. P. M. , Chen James T.
Published: March 2011

The incorporation of nitrogen and hydrogen during nitridation of SiO2 was studied over the temperature range of 800–1000°C and for ammonia pressures of 1, 5 and 10 atm. The nitrogen content of the nitrided films was determined with Rutherford backscattering spectrometry. Nitrogen in-depth profiles were obtained applying Auger analysis combined with ion-sputtering. Hydrogen profiles in the films were measured using nuclear reaction analysis. Both the nitrogen and hydrogen incorporation were found to increase with temperature in this range. A higher ammonia pressure primarily increases nitridation of the bulk of the oxide films. Depending on the nitridation conditions up to 10 at.% of hydrogen may be incorporated. As distinct from the nitrogen profiles, the hydrogen in-depth profiles are essentially flat. The concentration of hydrogen in the films, however, was always found to be smaller than that of nitrogen : measured H/N ratios varied between 0.09 and 0.85, the smaller values being obtained for the thinner oxides and higher nitridation temperatures. The model previously postulated to explain the nitrogen incorporation during atmospheric nitridation of SiO2 proves to be valid at higher pressures as well. By considering the role of OH as reaction product of the nitridation process, the hydrogen results can be accommodated within the same concept. The model predicts a low H/N incorporation ratio for a thin surface and interface layer and a substantially larger ratio for the bulk of the film. If this prediction is correct, which seems to be indicated by the etch-rate behaviour of the nitrided oxides, then this would have considerable importance for the electrical properties of this material.
Growth and Composition of LPCVD Silicon Oxynitride Films
Authors: Habraken F. H. P. M. , Kuiper A. E. T.
Published: March 2011

Silicon oxynitride films with various O/N concentration ratios were deposited in a Low Pressure Chemical Vapour Deposition process from SiH2Cl2, N2O and NH3 or ND3. The resulting films were analysed with respect to their chemical compositions using a number of high energy ion beam methods. The results of the analysis are related to the growth kinetics. It is suggested that the SiH2Cl2 decomposes more difficult on growth surfaces which contain more oxygen. The effect is attributed to the larger electronegativity of oxygen compared to nitrogen.
Concentration Measurements and Depth Profiling of Phosphorus and Boron by Means of (p,γ) Resonant Reactions
Authors: Pruppers M. J. M. , Zijderhand F. , Habraken F. H. P. M. , van der Weg W. F.
Published: March 2011

Small concentrations of phosphorus and boron in thin films have been measured by detection of proton induced prompt γ-rays. This technique is almost free of interference from other elements in the film or the substrate. Furthermore it is possible to obtain depth information without sputtering. The detection limit of both elements is around 100 ppm; depth resolution at shallow depths in silicon is about 50 nm in the case of boron, whereas it is better than 10 nm in the case of phosphorus.

As an application of this method, the incorporation of phosphorus and boron in thin films of hydrogenated amorphous silicon is measured. The films were prepared in a glow discharge reactor by mixing PH3 or B2H6 with the SiH4/H2 gas mixture.
Influence of the Density of Oxide Particles on the Diffusional Behavior of Oxygen in Internally Oxidized, Silver-Based Alloys+
Authors: Sanchez F. H. , Mercader R. C. , Pasquevich A. F. , Bibiloni A. G. , Lopezgarcia A.
Published: March 2011

This paper presents strong evidence for the influence of the density of oxide particles on the internal oxidation kinetics of silver based alloys. Measurements performed by Mbssbauer Spectroscopy, on 1 at% Sn in Ag alloys oxidized at temperatures between 523 and 823K, clearly indicate that the oxidation kinetics are described by a power law of the time with an exponent close to the unity for a high density of oxide particles (between 0.3 and 1.0×10−2 oxide particles per alloy atom). For low densities (<10−4 oxide particles per alloy atom), the exponent is close to 0.5). Previous kinetics measurements in AgIn alloys are shown to be in general agreement with this rule. These results can be interpreted on the basis of the existence of strain fields around the oxide particles, which produce a network of channels for easy oxygen migration when the density of oxide particles is high enough.
The Use of Energy Loss Structures in XPS Characterisation of Surfaces
Authors: Castle J. E. , Abu-Talib I. , Richardson S. A.
Published: March 2011

This paper describes advances in the use of the energy loss background associated with individual photoelectron peaks. The subtraction of a Shirley-type background is now normal practice in quantitative XPS analysis. However, in the case of a composite peak containing features from differing depths the subtraction of a common background has a clear disadvantage: i.e. the proportion of background rise associated with each component should be different but is, in fact, fixed. A peak-fitting procedure is described which enables individual backgrounds to be used for each component. The method has been tested using evaporated overlayers and this enables a mean free path for electrons undergoing small energy losses (less than 10 eV) to be determined. The findings are in accord with those of Tougaard and Sigmund and suggest that the use of background intensities in conjunction with the peaks themselves enables the information depth of XPS to be extended by about 10%. A few observations on the behaviour and use in analysis of the large energy loss structure are made.

The use of the findings to aid in characterisation of the near surface distribution of elements and ions is described for the following systems: the distribution within oxide films on alloys; the locus of disbondment of organic films on metals; and the surface contamination of surfaces removed from aqueous media.
Surface Electronic Function Properties Characterization from Defect Heterogeneity Dominated Specular/Glancing/Grazing Versus Bulk Transmission Small-Angle-Scattering(SAS) Diffraction-Pattern via the Static Synergetics Algorithm/Exprimental Model
Authors: Siegel Edward
Published: March 2011

The ability of Static Synergetios,the universal,reversible,scalable mathematical algorithm/(used as an) experimental model, connecting external radiation small-angle-scattering diffraction-pattern/static structure factor SSAS (k),dominated by defect heterogeneities/clumps/clusters,to electronic (magniic,mechanical) complex,frequency-dependent electrical,dielectric, noise,optical…Function properties,can be enhanced by utilizing a comparison/difference of bulk transmission versus surface specular/glancing/grazing incidence small-angle-scattering diffraction-patterns.
Core-Level Electron Binding Energy Change of Evaporated Pd
Authors: Kohiki Shigemi
Published: March 2011

Positive core-electron binding energy shifts in small palladium clusters supported on cadmium telluride substrate are shown to arise from the initial-state effects those are more sensitive to cluster size than are the final-state properties and the mean valence band electron binding energy is primarily responsible for the Pd 3d5/2 electron binding energy in lower coverage region (Pd ≲ 1×1015 atoms-cm−2).
Depth of Penetration of the Plasma Fluorination Reaction into Various Polymers
Authors: Wildi Eve A. , Scilla Gerald J. , DeLuca Alan
Published: March 2011

The surfaces of a variety of polymers presenting either primary, secondary, tertiary, vinyl or aromatic protons to the reactive gas environment were fluorinated by glow discharge treatment. Depth profiles of the plasma surface reaction were obtained by SIMS with oxygen ion sputtering. Further information was obtained from the appearance of ESCA traces of these substrates before and after the reaction.
Microstructural Study of Devitrified Amorphous Alloys
Authors: Vassamillet Lawrence , Maringer Robert , Carbonara Robert , Mccall James
Published: March 2011

Several amorphous alloys were subjected to thermal processing subsequent to their rapid solidification. These alloys have been characterized utilizing metallographic (optical, TEM, and SEM) and x-ray methods. Also, mechanical property evaluations have been made. The alloys exhibit extremely fine grain size; some have a high degree of preferred orientation and second-phase precipitates in the submicron size range. Most have good modulus, high yield and ultimate strength, high reduction in area but limited percent elongation.
Some Advantages of EDS Analysis in a 400 KV Electron Microscope
Authors: Suzuki S. , Honda T. , Bando Y.
Published: March 2011

The dependence of the characteristic and bremsstrahlung X-ray counts, the peak to background (P/B) ratio and the spatial resolution on the incident beam energy between 100 keV and 400 keV were measured using a high voltage electron microscope (HVEM). The bremsstrahlung count decreases much faster than that of the characteristic count with the increase of the incident beam energy. The decrease rate depends on Z number. It is ascertained that the P/B ratio and the spatial resolution at 400 keV were 2 or 3 and 2.5 times better than those at 100 keV, respectively.
Electron Energy-Loss Spectroscopy in a 400kV Transmission Electron Microscope (TEELS)
Authors: Oikawa T. , Hosoi J. , Kokubo Y. , Bando Y. , Lehman J. L.
Published: March 2011

Electron energy-loss spectroscopy in the transmission electron microscopy (TEELS) is a powerful technique to investigate the “electron and atom interaction in specimen microareas”.

This paper reports some experimental data of TEELS concerning specimen thickness effect and advantages of 400 kV TEM, and introduces newly developed digital processing of EELS spectra, which is a powerful technique to get the information from the specimen materials.
The Application of Analytical Electron Microscopy to Improving the Sensitization Resistance of Type 304 Stainless Steels
Authors: Betrabet H. S. , Clark W. A. T.
Published: March 2011

The sensitization resistance of austenitic stainless steels can be improved by replacing some of the C with N. Electrochemical potentionkinetic reactivation (EPR) tests indicate that this is effective up to∼0.16 wt.%N, but that above this level sensitization is enhanced. Thermodynamic calculations indicate that N should continue to reduce sensitization up to at least 0.25 wt.%N, as it retards the growth kinetics of Cr carbides. Analytical electron microscopy was used to investigate this apparent conflict and showed that, while N did decrease the volume diffusion coefficient of Cr beyond 0.16 wt.%, an increase in the amount of discontinuous precipitation of carbides with increasing N was responsible for the sensitization at higher N levels.
Determination of Phase Diagrams by AEM
Authors: Ayer Raghavan
Published: March 2011

Determination of phase diagrams to understand the equilibria among phases in metallic and ceramic systems has been of paramount interest in many areas of materials research. Traditionally, phase diagrams have been determined by (i) selecting several experimental compositions to map the region in the system of interest, (ii) exposing the alloys to temperature to achieve equilibrium, and (iii) characterizing one or more of the physical properties of the bulk material such as the crystal structure(s), magnetic property, metallography, etc., to determine the number and type of phases present in each alloy. Phase boundaries are then determined by delineating the regions of alloy compositions with respect to the number and types of phases present. The traditional methods suffer from several drawbacks, the major ones being (i) the need for numerous samples, (ii) difficulties in accurately determining multi-phase regions, (iii) assumption that the bulk samples are macroscopically and microscopically homogeneous, and (iv) difficulties in establishing the attainment of equilibrium. The limitations of these traditional methods mainly stem from their inherent inability to characterize the crystal structure and composition of the individual phasesCI). More recently, methods have been developed to determine phase boundaries by x-ray microprobe analysis of bulk diffusion couples (2). Though this approach offers some advantages over the conventional methods, it is still limited by the poor spatial resolution of x-ray microprobe analysis.
Measurement of Equilibrium and Nonequilibrium Segregation by X-Ray Microanalysis
Authors: Kenik Edward A.
Published: March 2011

X-ray microanalysis in an analytical electron microscope is a proven technique for the measurement of solute segregation in alloys. Solute segregation under equilibrium or nonequilibrium conditions can strongly influence material performance. X-ray microanalysis in an analytical electron microscope provides an alternative technique to measure grain boundary segregation, as well as segregation to other defects not accessible to Auger analysis. The utility of the technique is demonstrated by measurements of equilibrium segregation to boundaries in an antimony containing stainless steel, including the variation of segregation with boundary character and by measurements of nonequilibrium segregation to boundaries and dislocations in an ionirradiated stainless steel.
The Use of Symmetry in the TEM Analysts of Precipitate Morphologies
Authors: Dahmen U. , Westhacott K. H.
Published: March 2011

This study points out how symmetry properties inherent in precipitation reactions can be exploitet to facilitate and improve the accuracy of a morphological analysis by TEM. A method is given for the simple determination of the direction and distribution of needle precipitates and the habit plane of plate precipitates based on the use of symmetry properties of the matrix crystal. The bicrystal symmetry of different orientation relationships between cubic crystals and its connection with observed and equilibrium shapes is illustrated with examples of high resolution micrographs of Ge precipitates in an Al matrix.
Contributions of Electron Microscopy to the Understanding of Reactions on Compound Semiconductor Surfaces
Authors: Sands T.
Published: March 2011

Reacted films on compound semiconductor substrates present challenging materials characterization problems which often require the application of transmission electron microscopy (TEM) techniques. In this paper, both the problem - solving potential of the TEM techniques and the limits imposed by preparation of thin film/compound semiconductor TEM specimens are discussed. Studies of the Ni/GaAs, CuCl(aq)/CdS and Pd/GaAs reactions exemplify the role of TEM in identifying and determining the spatial distribution of interface - stabilized polymorphs and new ternary phases (e.g. tetragonal Cu2S, Ni3GaAs and PdxGaAs). These examples also serve to clarify the relationship between TEM and complementary analysis techniques such as Rutherford backscattering spectrometry, Auger electron spectroscopy and glancing-angle x-ray diffraction. In particular, it is argued that a combination of (1) high-spatial-resolution information obtained by TEM and (2) an indication of the “average” behavior provided by data from a complementary characterization technique provide the minimum quality and quantity of data necessary to understand most reactions on compound semiconductor substrates.
EDX and EELS Analysis of Precipitates in HSLA Steels
Authors: Chen Z. , Loretio M. H. , Cochrane R.
Published: March 2011

The sizes and compositions of precipitates in two weldable HSLA steels have been determined using analytical electron microscopy. It has been shown that the balance between the microalloy additions must be carefully controlled if the formation of very large precipitates in the cast slab is to be avoided. These large precipitates are very stable, some having been shown to be stable on reheating to about 1200°C and others are stable up to the melting point of the steel. The significance of these observations is briefly discussed in terms of the influence of these precipitates on the properties of the microalloyed steels.
Commensuration and Discommensuration in the Ag-Mg Alloys
Authors: Fujino Y. , Sato H. , Otsuka N.
Published: March 2011

Commensuration and discommensuration characteristics of the long period superlattice in the Ag-Mg alloys near Ag3Mg with short modulation periods (M ≃ 2) are investigated. When quenched from 650°C, the modulation periods M of these alloys is found to take theoretical values determined by the size of the Fermi surface, while upon further annealing at low temperatures, alloys assume the commensurate structure M=2, except for those alloys with theoretical M values substantially different from 2. These alloys approach the periodic discommensuration structures of the type <2j1> or its variants whose average periods M are closest to the theoretical incommensurate values. This behavior leads to the conclusion that the formation of the long period superlattice in these alloys is basically due to the CDW formation and that the commensuration and the discommensuration characteristics are determined by the free energy of the modulation boundaries.
High Resolution Electron Microscopy of Triply Incommensurate Phase of 2H-TaSe2
Authors: Onozuka Takashi , Otsuka Nobuo , Sato Hiroshi
Published: March 2011

The triply incommensurate phase of 2H-TaSe2 obtained by cooling from the normal phase was investigated by TEM between 87K and 113K with the resolution of 3 A. Moire-like patterns observed in this phase were confirmed to be interference fringes due to the first and the second order diffraction beams from the incommensurate structure and were not due to the dark field diffraction contrast of domains of the commensurate structure as interpreted earlier. Lattice fringes (∼9Å) of this modulated phase do not show any discontinuity across the boundaries of regions of different contrasts of the moire-like fringes which is expected from domain boundaries. Instead, a periodic change in the spacing of the lattice fringes (phase slip region) expected from the superposition of split superlattice spots in forming the lattice image is observed. This is the first direct observation of the existence of the phase slip region which is also expected from the discommensuration theory.
The Core Structure of Dislocations in GaAs
Authors: De Cooman B. C. , Kuesters K.-H. , Carter C. B.
Published: March 2011

The structural aspects of dislocations in GaAs which had been plastically deformed at high stress were studied by TEM. The glide of well-defined dislocations in their slip-plane was observed during the recombination-enchanced relaxation of the dislocations from their high-stress configuration. The strong asymmetry of dislocation velocity previously observed by other techniques is confirmed. High-resolution, electron micrographs of dissociated end-on screw dislocations were compared to computer simulated micrographs of model structures of the dislocation core. No definite conclusion regarding the exact core structure could be made due to the movement of the defects during the observation.
Morphological Developments of Nickel Particles in Supported Metal Catalysts
Authors: Dhere A. G. , De Angelis R. J. , Reucroft P. J. , Bentley J. , Ice G. E. , Habenschuss A.
Published: March 2011

The morphology of nickel-containing phases at each stage during the treatment of a 12%Ni/SiO2 catalyst was studied. Liquid impregnated catalyst initially shows nickel nitrate uniformly dispersed on the surface of the silica in the form of a film. After calcining, large rafts of NiO with faceted surface pits are seen. The reduced catalyst contains bunched nickel particles or large rafts on the surface of the silica.
High Resolution Imaging of As-Grown Sapphire Surfaces
Authors: Hsu Tung , Nutt S. R.
Published: March 2011

Surfaces of commercially grown edge-defined film-fed growth sapphire (EFG α-Al2O3) were studied in the electron microscope using both reflection electron microscopy (REM) and conventional transmission electron microscopy (TEM). The as-grown sapphire surface, ostensibly {1120}, was characterized by “rooftop” structures which were often locally periodic. These rooftop structures consisted of alternating {1120} facets and additional facets inclined a few degrees. The crystallography of the surface facets was analyzed using REM imaging of bulk specimens, and trace analysis of back-thinned plan section TEM specimens. Surface roughness was measured by stylus profilometry. and these measurements were compared to the electron microscopy observations. Fine structural features parallel to <0110> directions were also observed in both REM and TEM experiments, and these were attributed to surface steps of atomic scales.
Electron Microscopy of Ion Deposited Thin Films of the Oxides of Titanium
Authors: Harker A. B. , Howitt D. G. , Hood P. J. , Kobrin P.
Published: March 2011

The reactive ion beam deposition of ceramic films onto unheated substrates can produce amorphous films with essentially molecular mixing. The annealing and hot isotatic pressing (hipping) of these films to produce crystalline phases have reproducable effects which are sensitive to the temperature and the density of the film. Experiments with titanium oxides indicate that it is principally the equilibrium phases that are formed and that hipping can be used to encourage the same transformations at lower temperatures.

Thin films of titanium oxide close to the stoichiometry of TiO2 were deposited onto unheated substrates of sodium chloride. Some of the films were removed from the substrate by floating them off in water and the remainder were either annealed or hipped to induce crystallization. The anneals were performed either in air or argon and the hipping was done under an argon pressure of about twenty thousand pounds per square inch. Several of the free standing films were annealed in the same atmospheres on nickel grids. All the specimens were prepared for transmission electron microscopy by the same floating technique and were examined in a Philips 400 T.E.M. at 125 keV. The as deposited films were amorphous and showed no visible texture other than that derived from a small amount of porosity. The films were sufficiently conductive that they could be examined directly in the T.E.M. without carbon coating provided they were supported on a grid of fairly fine mesh. One specimen was also examined in the Kratos 1.5 MeV high voltage electron microscope at the National Center for Electron Microscopy. The specimen was annealed in vacuum using an in-situ hot stage to directly observe the behavior of the film.

The post deposition annealing and hipping of these films reproducibly induced the crystallization of anatase below 800°C. This is the equilibrium phase [1] and the extent to which the films transformed and the morphology of the growing crystallites were determined principally by the film thickness. There was little difference between the responses of free standing films and films left on the salt substrate. They tended to transform at about the same temperature, which was reproduced in the in-situ hot stage experiment and the microsructures which formed were very similar. The dependence upon thickness was also reflected in all the microstructures of the different post deposition treatments and it was possible to complete the transformations that were very sluggish in some of the films by hipping them at the same temperatures.