Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

It has long been thought that (111) surfaces of rock salt oxides microfacet to neutral surfaces upon annealing because of the very large energies involved in bulk terminating a layer of like ions. However in a recent reflection electron microscopy (REM) study Gajdardziska-Josifovska et al. found that MgO(lll) surfaces annealed in flowing oxygen furnaces at 1500°C not only did not microfacet, but displayed a √3×√3R30° surface periodicity that was stable in air. To determine the structure of this unusually stable surface MgO (111) transmission electron microscopy (TEM) samples were annealed in a vacuum furnace in the present study and their transmission electron diffraction (TED) patterns were analyzed with direct phasing methods.

The TEM samples were prepared by orienting a MgO single crystal and sawing lmm wafers along a (111) plane. Disk samples were then ultrasonically drilled, dimpled, mechanically polished and/or hot nitric acid etched, and milled with 5 KeV Ar+ ions.

Many industrial catalysts have a complex geometric structure to enable reacting gases or fluids to reach as much of the active surface of the catalyst as possible. The catalyzing surface frequently consists of a complex chemical mixture of different phases produced by an evolved chemical process. The active components are often very small particles dispersed on high-surface-area supports. The catalytic properties of this type of catalyst depend on the structure, composition, and morphology of the active species as well as the supports. TEM/STEM and associated techniques have been used extensively to characterize the structure and composition of supported catalysts. Surface morphology of supported catalysts is generally examined by secondary electron imaging, especially at low incident beam energies. It is, however, frequently found that small metal particles are not usually seen in SE images because of the complication of support topography

The issue of specimen contamination becomes more important at a rate proportional to the use of high-brightness electron source Transmission Electron Microscopes (TEM). These TEMs combine smaller electron probes with increased current, allowing high resolution specimen imaging and enhanced analytical data collection. Small, high current electron probes tend to increase the detrimental effect of hydrocarbon presence on the specimen's surface. The subsequent formation of carbon deposits caused by the focused probe often times obstructs imaging and precludes acceptable analytical results. by plasma cleaning the specimen, contamination is removed and the results obtained by high resolution electron microscopy (HREM), scanning transmission electron microscopy (STEM) and analytical electron microscopy (AEM) using EDS or electron energy loss spectroscopy (EELS) are greatly enhanced. Recent instrumentation developments have resulted in the application of a high frequency, low energy, reactive gas plasma generated in an oil-free vacuum that chemically removes hydrocarbon contamination from both the TEM specimen holder and the specimen without altering its properties.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

The increasing demand of sources of energy such as oil and natural gas induces at the steel industry a development on low carbon microalloyed steels for pipeline applications in order to achieve excellent mechanical properties of strength and toughness at a reduced cost. To obtain an adequate fine-grained final structure, the strict control of thermomechanical processing and accelerated cooling is crucial. Depending on the thermomechanical processing conditions and chemical composition, pipeline steels can present different microstructures. Several authors have found that the microstructure of acicular ferrite usually provides an optimum combination of mechanical properties. Higher levels of austenite strengthening before cooling promote a refinement of final microstructure but can also restrict the fraction of low temperature transformation products such as acicular ferrite.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.