Past, present, and future of backscatter electron (BSE) imaging

Wells, Oliver C.; Gordon, Michael S.; Gignac, Lynne

doi:10.1117/12.920001

Cited by 3 publications

(3 citation statements)

References 37 publications

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“…Therefore, the tubing repair process could consider a dissimilar-metal weld as well as a pre-heat treatment as an important parameter. The failure of the Ni-Cr-Fe alloy in the petrochemical industry has been studied, and the influence of carburization, carbide formation, thermal treatment conditions and welding repair technology has been investigated by some researchers [1][2][3][13][14][15][16][17][18][19].…”

Section: Weldability With Thermal Heat Treatmentmentioning

confidence: 99%

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The Study of Heat Treatment Effects on Chromium Carbide Precipitation of 35Cr-45Ni-Nb Alloy for Repairing Furnace Tubes

Srisuwan

Eidhed

Kreatsereekul

et al. 2016

Metals

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This paper presents a specific kind of failure in ethylene pyrolysis furnace tubes. It considers the case in which the tubes made of 35Cr-45Ni-Nb high temperature alloy failed to carburization, causing creep damage. The investigation found that used tubes became difficult to weld repair due to internal carburized layers of the tube. The microstructure and geochemical component of crystallized carbide at grain boundary of tube specimens were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) with back-scattered electrons mode (BSE), and energy dispersive X-ray spectroscopy (EDS). Micro-hardness tests was performed to determine the hardness of the matrix and the compounds of new and used tube material. The testing result indicated that used tubes exhibited a higher hardness and higher degree of carburization compared to those of new tubes. The microstructure of used tubes also revealed coarse chromium carbide precipitation and a continuous carbide lattice at austenite grain boundaries. However, thermal heat treatment applied for developing tube weld repair could result in dissolving or breaking up chromium carbide with a decrease in hardness value. This procedure is recommended to improve the weldability of the 35Cr-45Ni-Nb used tubes alloy.

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Section: Weldability With Thermal Heat Treatmentmentioning

confidence: 99%

“…The more heavy an atom is, the more a BSE signal can be generated, giving results in a brighter contrast. Therefore, the BSE is used to detect contrasts between areas with different elemental compositions [19,20]. Figure 4a,b shows the backscattered electrons images (BEI) of Specimen No.…”

Section: Materials Verificationmentioning

confidence: 99%

The Study of Heat Treatment Effects on Chromium Carbide Precipitation of 35Cr-45Ni-Nb Alloy for Repairing Furnace Tubes

Srisuwan

Eidhed

Kreatsereekul

et al. 2016

Metals

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“…It is well known that angle-resolved detection of electrons in specific energy ranges can provide useful imaging modalities in the SEM (Niedrig, 1978;Wells, 1979;Reimer, 1998;Rau & Reimer, 2001). With the widespread availability of advanced two-dimensional (2D) imaging detectors in the SEM, an improved experimental characterization of the pertinent effects involved and their correct theoretical description by computational simulations acquires renewed importance (Wells et al, 2012;Jaksch, 2012;Walker et al, 2016;Forbes & Allen, 2016). This is the more so important in the case of crystalline materials, for which the signal generation process can obviously be influenced by diffraction effects due to the local crystal lattice, providing orientation contrast in the SEM (Prior et al, 1996;Day & Quested, 1999;Wright & Nowell, 2006;Day, 2009;Schwarzer & Sukkau, 2013;Wright et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Diffraction effects and inelastic electron transport in angle‐resolved microscopic imaging applications

Winkelmann

Nolze

Vespucci

et al. 2017

Journal of Microscopy

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SummaryWe analyse the signal formation process for scanning electron microscopic imaging applications on crystalline specimens. In accordance with previous investigations, we find nontrivial effects of incident beam diffraction on the backscattered electron distribution in energy and momentum. Specifically, incident beam diffraction causes angular changes of the backscattered electron distribution which we identify as the dominant mechanism underlying pseudocolour orientation imaging using multiple, angle-resolving detectors. Consequently, diffraction effects of the incident beam and their impact on the subsequent coherent and incoherent electron transport need to be taken into account for an in-depth theoretical modelling of the energy-and momentum distribution of electrons backscattered from crystalline sample regions. Our findings have implications for the level of theoretical detail that can be necessary for the interpretation of complex imaging modalities such as electron channelling contrast imaging (ECCI) of defects in crystals. If the solid angle of detection is limited to specific regions of the backscattered electron momentum distribution, the image contrast that is observed in ECCI and similar applications can be strongly affected by incident beam diffraction and topographic effects from the sample surface. As an application, we demonstrate characteristic changes in the resulting images if different properties of the backscattered electron distribution are used for the analysis of a GaN thin film sample containing dislocations.

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