bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alchemi Analysis of Cation Distributions in Spinel-Structured Compounds Using Oxygen as a Marker Element
Authors: M. Anderson Ian 
Published: July 2020

Abstract
The establishment of ALCHEMI (atom location by channeling-enhanced microanalysis) as a viable microanalytical technique owes much to its early success in determining cation distributions in crystals having the structure of the mineral spinel, MgAl2O4. The first application of ALCHEMI was to a synthetic chromite spinel, and geological applications to natural mineral spinels containing multiple 3d transition elements provided many of the early applications of the technique. Spinel has three distinct regular lattice sites, two cation sites and one anion site, occupying the 8a, 16d and 32e Wyckoff positions of the Fd3m space group. In projection along (800), tetrahedrally coordinated (8a) cations occupy one set of alternate planes, whereas octahedrally coordinated (16d) cations and, to a good approximation, the anions occupy the other set. In principle, therefore, ALCHEMI performed at an 800 planar channeling condition could be used to analyze site distributions in spinel, using oxygen as a marker for the planes containing the octahedral cations, as was early noted.
Cation Coordination At Σ Grain Boundaries in TiO2 and SrTiO3, and its Effect on the Local Electronic Properties
Authors: Zaborac JA , Buban JP , Moltaji HO , Stemmer S , Browning ND 
Published: July 2020

Abstract
Grain boundaries have long been known to have a dominant effect on the electronic properties of polycrystalline materials. In the case of electroceramic oxides, the thermodynamics of defect formation (vacancies or interstitials, cations or anions) are usually invoked to predict the presence of a space charge potential at the grain boundaries. The relative energetics for the formation of each type of defect determines the size and sign of this potential barrier and thus, the effect that boundaries have on the overall electronic properties of the materials. However, a limitation to this continuum thermodynamics approach is that it does not consider the effect of the grain boundary structure.
To investigate whether the grain boundary atomic structure can have an effect on the energetics of defect formation and hence the electronic properties, here we examine the structure of Σ5 boundaries in two systems, SrTiO3 (perovskite) and TiO2(rutile).
Segregation of Ba to Cr Thin Film and Glass Interfaces
Authors: Jiang N , Silcox J 
Published: July 2020

Abstract
The knowledge of interface properties is important in understanding the adhesion of metal films to glasses. To simplify the analysis, silicate glasses are usually regarded as amorphous SiO2. Comparing the measured energy loss functions of Code 7059 (BaO-B2O3-SiO2) and Code 1737 (Al2O3-B2O3-Si2) glasses by EELS with the calculated result of a-Si02 from optical data, this is a fairly good assumption in bulk materials. Depositing metals, which have strong affinity for oxygen on glasses, however, may result in minor elements, such as Ba in both 7059 and 1737 glasses, segregating to interfaces, and breaking down the chemical balance.
Figs. 1 and 2 show the EELS spectra acquired with a 2Å electron probe in Cr film, interface and bulk glass respectively. The Cr film in Fig. 1 was sputtered on 7059 glass at room temperature, and annealed at 450°C in compressed Ar gas for 10 min. The preparation of Cr thin film in Fig. 2 is mentioned elsewhere.
Statistical Analysis Of SEM-EDX Spectrum Images Of A Metal-Ceramic Braze
Authors: Kotula PG , Anderson IM , Stephens JJ 
Published: July 2020

Abstract
Spectrum imaging, where a complete spectrum is acquired at each pixel in an image, is potentially a very powerful technique for the characterization of materials. The primary challenge to overcome is to extract all of the relevant information from what are typically large data sets that cannot be readily visualized in their entirety. For energy-dispersive X-ray (EDX) spectrum images, simple mapping has typically been done. In this work, the application of multivariate statistical analysis (MSA) to the characterization of a metal/alumina braze by SEM-EDX spectrum images is described.
The braze characterized in this work joins polycrystalline alumina and a copper-silver eutectic alloy containing some titanium (an ‘active’ metal). The specimen geometry consisted of a sandwich of two pieces of alumina, two braze layers and a Kovar (primarily Fe, Ni and Co) filler layer in the middle. The entire assembly was heat-treated to bond the interfaces and then a polished cross-section was prepared.
Characterization and Production of Structurat Ceramics in the Systems Fe(1-X)O-Fe3O4 and MgO-MgFe2O4.
Authors: Huerta A , Ordoñez R , Calderon HA , Umemoto M , Tsuchiya K , Balmori H , Reguera E , Yee-Madeira H 
Published: July 2020

Abstract
Ceramic materials are widely studied for their high temperature structural applications. In many crystalline ceramics the range of solid solution decreases with temperature and thus precipitation of a second phase occurs. Thus, ceramics can be hardened by precipitation of second phases. However little is known regarding the effect of precipitation and nanocrystalline grain structure in the ductility of ceramic materials. On the other hand, oxide ceramics are under intense-investigation for their technological advantages in magnetization, dielectric response and chemical stability in such diverse uses as magnetic recording media, induction cores and microwave resonant circuits. This investigation has been undertaken to produce, characterize and measure the properties of ceramics that can be hardened by precipitation. The selected systems include Fe(1-x)O-Fe3 and MgO MgFe2O4. Mechanical milling is used to produce nanocrystalline ceramic oxides in the systems Fe(1-x)O-Fe3 and MgO-MgFe2O4 The mechanically alloyed powders are consolidated by means of spark plasma sintering (SPS) at temperatures ranging from 673 K to 1273 K and a pressure varying from 500 to 50 MPa in vacuum.
Wetting of Anorthite Liquid On m-Sapphire Substrates
Authors: Ravishankar N , Ramamurthy S , Schmalzried H , Barry Carter C 
Published: July 2020

Abstract
The equilibrium condition for a liquid droplet in contact with a smooth, homogeneous, isotropic, non-deformable surface is given by the celebrated Young-Dupre equation1. This equation is based on the balance of the horizontal forces acting on the droplet. The idealised assumptions involved in arriving at the equation are seldom met in real experiments. Recently, Saiz et al have discussed the case of ridging of the solid at the three phase boundary (solid-liquid-vapour boundary) as a requirement for a stable three-phase co-existence. The wetting of anorthite on. sapphire substrates of different orientations have been studied earlier. In the present study, the wetting of anorthite liquid on m-plane of sapphire has been studied. The m-plane of sapphire is known to reconstruct in to two sets of facets and thus provides an interesting opportunity to study the wetting of liquid on a nonsmooth surface which contains linear patches with different surface energies.
Microanalysis in the Development of Thermal-Sprayed Anodes for the Cathodic Protection of Reinforced Concrete Bridges.
Authors: Collins WK , Cramer SD , Covino BS , Govier RD , Holcomb GR , Bullard SJ , Laylor M 
Published: July 2020

Abstract
Microanalysis has proved crucial in developing thermal-sprayed metal coatings on the surface of reinforced concrete to serve as anodes in impressed current (ICCP) and galvanic (GCP) cathodic protection systems and in understanding their long-term performance. Corrosion of reinforcing bar in concrete bridges is the primary cause of structural deterioration in high chloride environments such as coastal locations and colder climates where roads are deiced with salt. Over 40 pet of more than 500,000 bridges surveyed in the U.S. are in need of repair or rehabilitation. Cathodic protections is the most effective method of mitigating the effects of corrosion due to chloride contaminated concrete. While a young technology, consumable thermal sprayed zinc anodes (see Figure 1 for a schematic of the process) totaling over 40,000 m2 (430,00 ft2) have been installed on the Oregon coast, primarily on the Depoe Bay, Yaquina Bay, and Cape Creek bridges.
High Resolution TEM of Post-Deposition Ion Implanted C-BN Films
Authors: Dolukhanyan T , Gunasekara S , Byon E , Lee SW , Lee SR , Sung C 
Published: July 2020

Abstract
Post-deposition ion implantation of boron nitride (BN) films is to be considered as a powerful method for improvement of adhesion between films and substrates and reduction of compressive stresses, which usually accompany the growth of cubic BN.
The goal of this investigation is microcharacterization of as-deposited and ion-implanted BN films to better understand effect of ion implantation on microstructure of the films and film/substrate interface. High Resolution TEM (HF-2000 with field emission gun) has been utilized because of nanocrystalline dimensions of both cubic (c-) and hexagonal (h-) BN phases.
BN films have been deposited on (100) oriented Si substrates by magnetically enhanced activated reactive evaporation2. Plasma source ion implantation has been performed to make surface modifications and to improve the adhesion of the films. X/S specimens for TEM and HRTEM have been prepared in a routine manner, using G-1 epoxy for coupling the specimens, Dimpler VCR D500I, and Gatan Precision Ion Polishing System for final thinning.
Microstructural Evolution in Al-Ti Multilayered Film with Annealing
Authors: Mitra R , Chiou WA , A.Madan  , Hoffman R , Weertman JR 
Published: July 2020

Abstract
There has been a significant interest in the development of dispersion-hardened aluminum for many years for high specific strength and modulus. Such materials are usually processed by powder or ingot metallurgy routes. In this study, Al3 Ti dispersion hardened Al was obtained by annealing Al-Ti multilayers. Al-Ti multilayered films have been characterized in the past by observing the structure of the layers, as well as tensile properties and hardness. This paper reports the structure of Al-Ti multilayers and the evolution of matrix and dispersoid microstructure on annealing.
The Al-Ti multilayered structures were prepared by magnetron sputtering using Al and Ti as targets and either Si (100) or NaCl as substrates. The bi-layer thickness was maintained around 16 nm with Ti constituting 12% of the total. The substrate was alternately moved below the Al and Ti targets for the purpose of deposition. The as-deposited film on the substrate and NaCl salts were annealed at 400°C for periods between 1 and 24 h in a vacuum (10−5 torr) furnace.
Interfacial Elemental Distribution In Tungsten Carbide Coated Steel
Authors: Naidu SV , Green Carlos , Maxie Christopher , Garber James D , Glass Gary A 
Published: July 2020

Abstract
Thermal spray of carbide coatings with high hardness and corrosion resistance onto steel substrates has technological importance. The adhesive strength is greatly effected by the interfacial impurities. Low porous and good quality 200 μm thick 86WC10Co4Cr coatings on 4140 steel are obtained by thermal spray methods using SC-HVOF gun at Cooper Oil Tools, Houston, TX. A Carl Zeiss DSM942 SEM with 3.5 nm resolution at 30 keV and Kevex LPX1 Super Dry Quantum Si(Li) Detector with &lt; 145 eV resolution for Energy Dispersive X-ray Spectroscopy (EDXS) were used to study the elemental distribution across the interface. Fig. 1 shows the SEM micrographs of the interface between 86WC10Co4Cr thermal spray coating and 4140 steel substrate. The anchor patterns seen at the interface are believed to improve the adhesive qualities between the coating and the substrate.
Influence of Triple Junction Structure on Cu Segregation in Al Thin Films
Authors: Wauchope CJ , Keller RR , Sanchez JE 
Published: July 2020

Abstract
Al thin films, used as interconnects in integrated circuit devices, are subject to voiding failures due to electromigration and stress. Electromigration is a diffusion process and voids are known to form at points of flux divergence such as triple junctions. Void formation in Al-Cu films has also been associated with 9θ-phase (Al2 Cu) precipitates [1], which form preferentially at grain boundaries and triple junctions. Some triple junctions are favored as nucleation sites [2], presumably due to energetic differences arising from the crystallographic nature of the junctions. Their character can be calculated from the crystallographic orientations of the surrounding grains and the associated grain boundary dislocation networks [3]. Bollmann's method of analysis results in two categories of triple lines: I-lines - the special case where the grain boundary dislocations balance; and U-lines - the general case where the dislocation arrays do not balance. U-lines should have higher energies than I-lines and should therefore behave differently [3, 4]. This paper investigates the relationship between triple-line character and the location of Al2 Cu precipitates at certain triple junctions in Al-lCu thin films.
Determination of the Structure and Chemistry of Thermally Grown Oxides in Thermal Barrier Coatings
Authors: Brickey MR , Lee JL 
Published: July 2020

Abstract
Thermal barrier coatings (TBCs) insulate gas turbine hot section components from the hot (∽1200 - 1450°C) combustion gas exhaust stream. An airline company can save millions of dollars per year by using TBCs to protect vital engine components and to improve fuel efficiency. TBCs typically consist of an 8 wt.% yttria-partially-stabilized zirconia (YPSZ) ceramic topcoat deposited on a platinum-nickel-aluminide (Pt-Ni-Al) bondcoat covering a nickel-based superalloy substrate. Thermal exposure during YPSZ electron beam-physical vapor deposition (EB-PVD) and engine operation promotes the formation of a thermally grown oxide (TGO) between the Pt-Ni-Al and the YPSZ layers. Stresses can develop at the Pt-Ni-Al/TGO and TGO/YPSZ interfaces due to TGO growth and thermal expansion coefficient mismatch. These stresses eventually cause spallation of the YPSZ, leaving the metallic substrate vulnerable to high temperature degradation since exhaust temperatures are often higher than the melting temperature of most nickel-based superalloys (∽1200 - 1450°C).
Dislocation Substructure Contributions to the Tonal Qualities of the Caribbean Steel Drum - A TEM Study
Authors: Ferreyra E , Murr LE 
Published: July 2020

Abstract
Deformation substructures, especially dislocations, play an important role in the fabrication of the Caribbean steel drum and experimental evidence also suggests dislocations play a crucial role in the harmonic tuning and related musical qualities as well. In this study, we have examined and compared the dislocation substructures in high-quality, low-carbon (0.04-0.06 weight percent carbon) steel drum heads as manufactured, and sections cut from variously deformed (10% to 50% reduction) drum head sections, including those patterned with musical notes and heat treated; utilizing TEM.
We have recently shown that the requisite heating of a steel drum over a narrow temperature range (200 to 500°C) prior to tuning actually involves strain aging. Fundamentally, strain aging in steels has been explained by dislocation theory, but as far as we know, no experimental proof exists. This study also attempts to examine the more fundamental issues in strain aging, especially as it applies in the development of a high-quality, musical steel drum instrument.
Microstostructural Developments in Chill-Cast and Directionally Solidified Ti-44Al-11Nb Alloys
Authors: Menon ESK , Halladay TR , Fox AG , Mahapatra R 
Published: July 2020

Abstract
Studies aimed at improvements in the properties of titanium aluminides continue and efforts on optimizing the microstuctural parameters and a variety of processing techniques have attracted significant attention. In particular alloy compositions containing Ti-44to48at%Al and Nb as the major ternary addition (often with other minor alloying element additions) have been found quite promising. A fine fully lamellar structure in these TiAl-based intermetallic alloys has been reported to possess a combination of improved room temperature ductility, excellent fracture toughness, good oxidation resistance and creep properties. One of the serious problems associated with the TiAl-based alloys is the large grain size that develops in these alloys especially upon casting. A recent approach is to use directional solidification techniques in producing the TiAlbased alloys and it has been shown that desired orientations can indeed be produced by choice of suitable processing parameters.
In this study, we have examined the microstructural features associated with chill-cast as well as directionally solidified Ti-44at%Al-l lat%Nb alloy.
Microstructure of Laser Surface Melted Nickel Aluminum Bronze
Authors: Bennett JC , Hyatt CV 
Published: July 2020

Abstract
The copper alloys commonly referred to as nickel aluminum bronzes (NAB) are widely used in marine applications due to their excellent seawater corrosion resistance and good mechanical properties. Unfortunately, these alloys are susceptible to a variety of surface sensitive degradation processes such as cavitation and wear which significantly reduce service life. Laser surface melting and cladding techniques have recently demonstrated a potential to substantially enhance the performance of NAB components. This is associated with the occurrence of a martensitic or Widmanstätten transformation from the high temperature bcc β phase accompanied by precipitation of ordered intermetallic particles collectively referred to as κ. Optimization of these techniques requires an improved understanding of the evolution of microstructure in the NAB system under conditions of rapid solidification, however little data is currently available. In this paper, transmission electron microscopy is used to examine the microstructures of a series of laser surface melted NAB alloys containing from 8 to 12 wt. % Al, 3.8 to 6.5 wt. % Ni, 3.8 to 6.5 wt. % Fe, ∽1 wt. % Mn and, in some cases, lesser amounts of Ti or Zr.
New Transmission Electron Microscope Characterization Techniques from Precision Focused Ion Beam Membranes
Authors: Hull R , Dunn D , Demarest J , Mathes DT 
Published: July 2020

Abstract
The combination of focused ion beam (FIB) sputtering with transmission electron microscopy (TEM) offers new opportunities for the nanoscale characterization of materials. The FIB may be used to prepare membranes for TEM imaging which are: (i) Site selective, i.e. the membranes may be placed with sub-micron precision in all three dimensions, (ii) Largely free of differential sputtering artifacts, such that membranes may be prepared which are of constant thickness from structures with very dissimilar materials, and (iii) Of precisely known geometry.
The challenges associated with FIB specimen preparation will also be discussed and are summarized in Figure 1: (a) Surface amorphization damage, (b) Residual differential sputtering effects, (c) Redeposition of sputtered material and (d) Membrane bowing due to internal or beaminduced stresses. It will be demonstrated that each of these effects can be sufficiently controlled to allow high quality diffraction contrast imaging in a wide range of materials.
The FIB Lift-Out Specimen Preparation Technique for TEM Analyses and Beyond: SEM, AUGER, STEM, and SIMS Applications
Authors: Stevie FA , Vartuli CB , Mills RH , Irwin RB , Shofner TL , Giannuzzi LA 
Published: July 2020

Abstract
The use of focused ion beams (FIB) to prepare site specific specimens for transmission electron microscopy (TEM) and scanning electron microscopy (SEM) has been well documented. The 5 to 7 nm resolution on the latest FIB instruments has enhanced the ability to locate and expose features of interest. The use of the lift-out technique of FIB specimen preparation removes the need for prior thinning of the sample for TEM analysis and permits the study of materials that were difficult or impossible to do previously. Use of high current (10 nA) FIB instruments makes specimen preparation possible in less than one hour; automatic operation of FIB instruments will further reduce this time. After milling in the FIB, specimens are micromanipulated in air onto a 3 mm diameter TEM sample grid coated with carbon. The ability to analyze lift-out specimens using other analytical techniques that can take advantage of this site specific capability was previously suggested.
Precision FIB TEM Specimen Preparation ‘at a Distance’
Authors: Malis T , Buseck PR , Bradley JP , Li J , Phaneuf M 
Published: July 2020

Abstract
There is a trend in electron microscopy towards centralization of the more sophisticated EM systems. The rationale is that the techniques associated with such instrumentation are more efficiently practiced and developed by dedicated specialists in a regional or national centre surrounded by an extensive infrastructure. A similar argument can be used for the preparation of TEM specimens, especially as the demand grows for more precise location of the thin area to be examined. A new trio of techniques - tripod polishing, ultramicrotomy, and focused ion beam (FIB) thinning - can locate the thin area to within a micron or less. In the first two, a linear feature first located via light or scanning electron microscopy can be cross-sectioned by controlled material removal via mechanical polishing or diamond knife sectioning, respectively. With FIB, feature location and material removal are carried out in-situ, first imaging with a low intensity beam, then milling trenches on either side of the feature with a high intensity beam that is decreased as the feature is approached.
Transmission Electron Microscope Specimen Preparation of Metal Matrix Composites Using the Focused Ion Beam Miller
Authors: Cairney JM , Smith RD , Munroe PR 
Published: July 2020

Abstract
The focused ion beam (FIB) miller has been widely accepted as a powerful tool in the semiconductor industry. However, it is now finding applications in more general materials science applications. The high resolution, energetic gallium ion beam can rapidly and precisely section materials to reveal their internal structure; one particularly valuable application being the preparation of thin foils for TEM examination, especially from heterogenous materials.
To date, TEM sample preparation using FIBs has concentrated on semiconductor cross-sections [1], powders [2], and surface treated materials, e.g. galvanized steels [3]. However, thin foils of grossly heterogeneous materials, such as metal-matrix composites, are also difficult to prepare using conventional methods and are therefore well suited to sectioning using the FIB. In this study, thin foils were prepared from two composite materials: a 7075 aluminium alloy containing a 20% volume fraction of SiC particles and a FeAl alloy containing a 60% volume fraction of WC particles.
Effect of Surface Roughness on STEM Samples Prepared by FIB
Authors: Vartuli CB , Stevie FA , Kamino T 
Published: July 2020

Abstract
The Scanning Transmission Electron Microscope (STEM) can provide images beyond Scanning Electron Microscope (SEM) capability, on samples which do not have to be prepared to the degree required for Transmission Electron Microscopy (TEM). For some applications, such as semiconductor production, speed of analysis is critical. This paper explores Focused Ion Beam (FIB) sample preparation for STEM.
The samples were prepared using an Hitachi FB-2000A FEB tool. Two analysis regions of similar thickness were cut. The rough sample was milled using a 500 pA beam and no polish cut. The smooth sample was prepared by cutting first with a 500 pA beam, and then using additional, smaller diameter beams, concluding with a 30 pA beam. This resulted in a sample surface polished to a degree similar to that used for TEM specimens. The samples were imaged in an Hitachi HD-2000 STEM at 200KeV. Transmission electron images taken at 100 kx are shown in Figure 1 of the rough sample and of the smooth sample.