Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005

The ability to map plastic deformation around high strain gradient microstructural features is central in studying phenomena such as fatigue and stress corrosion cracking. A method for the visualization of plastic deformation in electron back-scattered diffraction (EBSD) data has been developed and is described in this article. This technique is based on mapping the intragrain misorientation in polycrystalline metals. The algorithm maps the scalar misorientation between a local minimum misorientation reference pixel and every other pixel within an individual grain. A map around the corner of a Vickers indentation in 304 stainless steel was used as a test case. Several algorithms for EBSD mapping were then applied to the deformation distributions around air fatigue and stress corrosion cracks in 304 stainless steel. Using this technique, clear visualization of a deformation zone around high strain gradient microstructural features (crack tips, indentations, etc.) is possible with standard EBSD data.

The oxidation state of iron oxide nanoparticles co-generated with soot during a combustion process was studied using electron energy-loss spectroscopy (EELS). Spatially resolved EELS spectra in the scanning transmission electron microscopy mode were collected to detect changes in the oxidation state between the cores and surfaces of the particles. Quantification of the intensity ratio of the white lines of the iron L-ionization edge was used to measure the iron oxidation state. Quantitative results obtained from Pearson's method, which can be directly compared with the literature data, indicated that the L3 /L2-intensity ratio for these particles changes from 5.5 ± 0.3 in the particles' cores to 4.4 ± 0.3 at their surfaces. This change can be directly related to the reduction of the iron oxidation state at the surface of the particles. Experimental results indicate that the cores of the particles are composed of γ-Fe2O3, which seems to be reduced to FeO at their surfaces. These results were also supported by the fine structure of the oxygen K-edge and by the significant chemical shift of the iron L-edge.

The M&M 2006 meeting will begin on Sunday, July 30, with a pre-meeting congress entitled “Materials Research in an Aberration-Free Environment.” The pre-meeting congress will share Sunday with a number of topical Short Courses addressing image processing and analysis, live cell imaging with fluorescence methods, scanning cathodoluminescence microscopy and spectroscopy, variable pressure and environmental SEM, and electron tomography. Examples of biological topics that will be addressed during the week of the meeting include: Cell Biology; Pathology; Microbiology; Microscopic molecular machines; Immunolabeling; and Photosynthetic organisms. Topical symposia in the physical sciences are: Nanoscience and nanotechnology; Catalysis; Quantitative X-ray microanalysis; Visualizing mechanical behavior; and Magnetic materials. In joint sessions for biological and materials scientists, symposia will address TEM automation, cryo-approaches for TEM, SEM and FIB/SEM, and surface microscopy. We honor the passing of Hans Ris with a special symposium on Cell Biology and Microscopy, and Art Chodos with a special symposium on Quantitative X-ray Microanalysis. Of special interest will be two 50th anniversaries: The first observation of dislocations, and the first experiments in elemental mapping by X-rays. Supplementing the topical sessions will be a number of tutorials and ask-the-experts sessions that will provide the opportunity to learn the basics behind several popular techniques. As always, the commercial exhibits will provide a unique opportunity for hands-on learning with the largest variety of state-of-the-art instrumentation found at any microscopy meeting worldwide.

Following is a list of microscopy-related meetings and courses. The editors would greatly appreciate input to this list via the electronic submission form found in the MSA World-Wide Web page at http://www.msa.microscopy.com. We will gladly add hypertext links to the notice on the web and insert a listing of the meeting in the next issue of the Journal. Send comments and questions to JoAn Hudson, [email protected] or Nestor Zaluzec, [email protected].

The oxide scales of AISI 304 formed in boric acid solutions at 300°C and pH = 4.5 have been studied using X-ray photoelectron spectroscopy (XPS) depth profiling. The present focus is depth profile quantification both in depth and chemical composition on a molecular level. The roughness of the samples is studied by atomic force microscopy before and after sputtering, and the erosion rate is determined by measuring the crater depth with a surface profilometer and vertical scanning interferometry. The resulting roughness (20–30 nm), being an order of magnitude lower than the crater depth (0.2–0.5 μm), allows layer-by-layer profiling, although the ion-induced effects result in an uncertainty of the depth calibration of a factor of 2. The XPS spectrum deconvolution and data evaluation applying target factor analysis allows chemical speciation on a molecular level. The elemental distribution as a function of the sputtering time is obtained, and the formation of two layers is observed—one hydroxide (mainly iron–nickel based) on top and a second one deeper, mainly consisting of iron–chromium oxides.

Amorphous 1–2-nm-wide intergranular films in ceramics dictate many of their properties. The detailed investigation of structure and chemistry of these films pushes the limits of today's transmission electron microscopy. We report on the reconstruction of the one-dimensional potential profile across the film from an experimentally acquired tilt series of energy-filtered electron diffraction patterns. Along with the potential profile, the specimen thickness, film orientation with respect to the grain lattice and specimen surface, and the absolute specimen orientation with respect to the laboratory frame of reference are retrieved.

Date Change: Microscopy and Microanalysis 2006 July 30–August 3, 2006 Chicago, Illinois, USA

Sponsor: Microscopy Society of America (MSA), Microbeam Analysis Society (MAS), International Metallographic Society (IMS)

URL: www.msa.microscopy.com

Following is a list of microscopy-related meetings and courses. The editors would greatly appreciate input to this list via the electronic submission form found in the MSA World-Wide Web page at http://www.msa.microscopy.com. We will gladly add hypertext links to the notice on the web and insert a listing of the meeting in the next issue of the Journal. Send comments and questions to JoAn Hudson, [email protected] or Nestor Zaluzec, [email protected].

Materials Research in Aberration-Free Environment (Saturday & Sunday)

Pre-meeting Congress Sponsors

Experimental results from the first monochromated and aberration-corrected scanning transmission electron microscope operated at 200 kV are described. The formation of an electron probe with a diameter of less than 0.2 nm at an energy width significantly under 0.3 eV and its planned application to the chemical analysis of nanometer-scale structures in materials science are described. Both energy and spatial resolution will benefit from this: The monochromator improves the energy resolution for studies of energy loss near edge structures. The Cs corrector allows formation of either a smaller probe for a given beam current or yields, at fixed probe size, an enhanced beam current density using a larger condenser aperture. We also point out another advantage of the combination of both components: Increasing the convergence angle by using larger condenser apertures in an aberration-corrected instrument will enlarge the undesirable chromatic focus spread. This in turn influences spatial resolution. The effect of polychromatic probe tails is proportional to the product of convergence angle, chromatic aberration constant, and energy spread. It can thus be compensated for in our new instrument by decreasing the energy width by the same factor as the beam convergence is increased to form a more intense probe. An alternative in future developments might be hardware correction of the chromatic aberration, which could eliminate the chromatic probe spread completely.

During lab-scale experiments on the reforming of methanol by means of water at supercritical conditions (T > 374°C, p > 22.1 MPa), a tubular reactor with a titanium liner was exposed to an aqueous solvent containing methanol (5 wt%) and KHCO3 (0.3 wt%). At the end of the run, a fibrous precipitate was found at two positions in the reactor. The material was studied in a field emission scanning electron microscope equipped with an energy dispersive X-ray analysis unit (FESEM/EDX). A thin-film support technique using carbon-filmed TEM grids was applied to perform scanning transmission-type imaging (STEM-in-SEM operation) and transmission current measurements. The analysis of the hydrothermally grown fibers resulted in a potassium titanate species composed of approximately K2TiO3, which has been confirmed by X-ray diffraction (XRD).

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Scanning electron microscopy (SEM) is widely used in the science of materials and different parameters were developed to characterize the surface roughness. In a previous work, we studied the surface topography with fractal dimension at low scale and two parameters at high scale by using the variogram, that is, variance vs. step log–log graph, of a SEM image. Those studies were carried out with the FERImage program, previously developed by us. To verify the previously accepted hypothesis by working with only an image, it is indispensable to have reliable three-dimensional (3D) surface data. In this work, a new program (EZEImage) to characterize 3D surface topography in SEM has been developed. It uses fast cross correlation and dynamic programming to obtain reliable dense height maps in a few seconds which can be displayed as an image where each gray level represents a height value. This image can be used for the FERImage program or any other software to obtain surface topography characteristics. EZEImage also generates anaglyph images as well as characterizes 3D surface topography by means of a parameter set to describe amplitude properties and three functional indices for characterizing bearing and fluid properties.

Zinc oxide (ZnO) nanoparticles have been produced using precipitation methods from ethanolic solution. Rare-earth metal doping was performed, and the effect of lithium codoping on the luminescence properties of the rare-earth doped products was assessed. The resulting particles were characterized using cathodoluminescence and scanning electron microscopy. It was found that lithium significantly enhanced the cathodoluminescence signal from the rare-earth ions, which has been attributed to the increased integration of the rare-earth ions into the ZnO structure. The nanophase ZnO products were also annealed in argon, hydrogen, and oxygen, with hydrogen being the most successful for removing the broad defect emission present in as-grown samples and enhancing the ZnO near band edge emission.

Following is a list of microscopy-related meetings and courses. The editors would greatly appreciate input to this list via the electronic submission form found in the MSA World-Wide Web page at http://www.msa.microscopy.com. We will gladly add hypertext links to the notice on the web and insert a listing of the meeting in the next issue of the Journal. Send comments and questions to Nestor Zaluzec, [email protected].

We report on the sub-electron-volt-sub-angstrom microscope (SESAM), a high-resolution 200-kV FEG-TEM equipped with a monochromator and an in-column MANDOLINE filter. We report on recent results obtained with this instrument, demonstrating its performance (e.g., 87-meV energy resolution at 10-s exposure time, or a transmissivity of the energy filter of T1 eV = 11,000 nm2). New opportunities to do unique experiments that may advance the frontiers of microscopy in areas such as energy-filtered TEM, spectroscopy, energy-filtered electron diffraction and spectroscopic profiling are also discussed.

X-11: Scanning Cathodoluminescence Microscopy and Spectroscopy, Full Day: 9:00 AM–5:00 PM, Room 301/303.

X-12: Digital Imaging 101: Scientific Imaging with Photoshop, Full day: 9:00 AM–5:00 PM, Room 302/304.

X-13: Digital Imaging 102: Image Processing and Analysis, Full Day: 9:00 AM–5:00 PM, Room 306.

X-14: Live Cell Imaging Using Fluorescence Methods, Full Day: 9:00 AM–5:00 PM, Room 305.

X-15: What To Do with a Variable Pressure (VPSEM) or Environmental SEM (ESEM) And How To Do It (Or At Least How It Ought To Work), Full Day: 9:00 AM–5:00 PM, Room 307.

X-16: 3-Dimensional Electron Microscopy (3DEM) in Life and Material Science—In-Depth Tutorial about Tomography—Basics and Methods, Full day: 9:00 AM–5:00 PM, Room 308.

X-17 Failure Analysis and Evidence Preservation by Metallography, Half day: 9:00 AM–1:00 PM, Room 309/311.

Special events: MSA and MAS presidential happenings, IMS Henry Clifton Sorby award and lecture, and art exhibit.

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

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