Interpretation of Electron Diffraction Patterns

Andrews, Kevin; Dyson, D. J.; Keown, S. R.

doi:10.1007/978-1-4899-6475-5

Cited by 271 publications

(161 citation statements)

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“…1c shows the microdiffraction patterns from two particles, consistent with <100> and <110> orientations of an FCC structure. The lattice parameter was measured by using the standard non-linear form of the Bragg Law, 19 and a value of 3.97 Å was obtained. An ultra-high-resolution HAADF image of Au/Pd nanoparticles is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Atomic structure of three-layer Au/Pd nanoparticles revealed by aberration-corrected scanning transmission electron microscopy

et al. 2008

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Aberration-corrected imaging is employed under the scanning transmission electron microscopy (STEM) mode to precisely determine the chemical ordering of Au/Pd nanoparticles. These colloids exhibit a core-shell structure with a three-layer arrangement that surprisingly presents alloying events in the observed layers. Aberration-corrected imaging is employed under the scanning transmission electron microscopy (STEM) mode to precisely determine the chemical ordering of Au/Pd nanoparticles. These colloids exhibit a coreshell structure with a three-layer arrangement that surprisingly presents alloying events in the observed layers. The study of nanomaterials can be greatly improved with the use of aberration-corrected transmission electron microscopy (TEM), which provides image resolutions at the level of 1 Å and lower. Sub-Å ngströ m image resolution can yield a new level of understanding of the behavior of matter at the nanoscale. For example, bimetallic nanoparticles are extremely important in catalysis applications; the addition of a second metal in many cases produces much-improved catalysts. In this paper, we study the structure and morphology of Au/Pd bimetallic particles using primarily the high-angle annular dark-field (HAADF) imaging mode in an aberration-corrected STEM/TEM. It is well established that, when recorded under appropriate illumination and collection geometries, incoherent HAADF-STEM images are compositionally sensitive and provide direct information on atomic positions. We matched the experimental intensities of atomic columns with theoretical models of three-layer Au/Pd nanoparticles, in different orientations. Our findings indicate that the surface layer of the nanoparticle contains kinks, terraces and steps at the nanoscale. The effect of adding a second metal induces the formation of such defects, which might very likely promote the well-known improved catalytic activity of this system.

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Section: Resultsmentioning

confidence: 99%

Atomic structure of three-layer Au/Pd nanoparticles revealed by aberration-corrected scanning transmission electron microscopy

et al. 2008

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“…The structure photographs and electron diffractions from extraction replicas were performed at an acceleration voltage of 100 kV. The carbide phase analysis was performed based on d hkl value given in previous publications (Ref 25,26). 100 200 300 400 500 600 700 Primary and secondary carbides -not dissolved during austenitization …”

Section: Metallographic Studies By Means Of An Electronmentioning

confidence: 99%

Transformations of Carbides During Tempering of D3 Tool Steel

Nykiel

Hryniewicz

2014

J. of Materi Eng and Perform

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The studies were performed on D3 tool steel hardened after austenitizing at 1050°C during 30 min and tempering at 200-700°C. Based on the diffraction studies performed from the extraction replicas, using electron microscopy, it was found that after 120-min tempering in the consecutive temperatures, the following types of carbides occur:Apart from higher mentioned carbides, there are also big primary carbides and fine secondary M 7 C 3 carbides occurring, which did not dissolve during austenitizing.

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“…Трав-ление предварительно полированной поверхности осуществляли плазмой газового разряда высокого давления на установке «КВИНТА» (ИСЭ СО РАН). Дефектную структуру материала изу-чали методами оптической (микроскоп «Микровизор металлогра-фический µVizo-MET-221»), сканирующей (сканирующий элек-тронный микроскоп 'SEM-515 Philips') и просвечивающей ди-фракционной (приборы ЭМ-125 и FET Tecnai 2062 TWIN) элек-тронной микроскопии [32][33][34][35]. Элементный состав поверхностно- [38][39][40].…”

Section: материалы и методы исследованияunclassified