Very-high spatial resolution analysis in STEM
| Autor: | A.J. Garratt-Reed |
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| Rok vydání: | 1983 |
| Předmět: | |
| Zdroj: | Proceedings, annual meeting, Electron Microscopy Society of America. 41:374-375 |
| ISSN: | 2690-1315 0424-8201 |
| DOI: | 10.1017/s0424820100075622 |
| Popis: | When analyzing a composition profile in a thin foil using a Scanning Transmission Electron Microscope, the measured profile is a convolution of the electron probe diameter, the actual profile and the degree of beam spreading in the sample. While it is possible to show that fractions of a monolayer of segregant are detectable in foils 100 nm thick, similar calculations indicate that if a probe 0.8 nm in diameter is incident upon a foil 20 nm thick, then broadening is insignificant. For example, fig. 1 is a computation (using the method of Hall, et.al) of the predicted measured profile resulting from a real gaussian distribution of chromium in iron, 2.5 nm wide, measured in the conditions just mentioned. Such results indicate that distributions of solutes well under 10 nm in separation should be readily distinguishable from each other.In some pearlitic steels, alloy elements are incompletely partitioned during the pearlite reaction, and subsequently diffuse from the ferrite into the cementite, where they form very narrow (∿ 2 nm wide) enriched zones either side of the cementite plate, which is itself around 10 nm thick. |
| Databáze: | OpenAIRE |
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