The identification of thin amorphous films at grain-boundaries in Al2O3

Simpson, Y. Kouh; Carter, C. B.; Morrissey, K. J.; Angelini, P.; Bentley, J.

doi:10.1007/bf00551474

Cited by 65 publications

(7 citation statements)

References 15 publications

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“…As the excited volume is significantly wider than the monolayer, the actual bismuth composition at the boundary is significantly higher (-50 atomic 96 Bi). Simpson et al (1986) have shown that a false indication of boundary segregation can result from the preferential collection of one element at surface grooves associated with a boundary. However, X-ray microanalysis of boundaries tilted away from edge-on configuration has shown that the segregation detected was associated with the boundary plane and not with the intersection of the boundary with the foil surfaces (i.e., not with bismuth present in surface grooves).…”

Section: Resultsmentioning

confidence: 99%

Loss of grain boundary segregant during ion milling

Kenik

1991

J. Elec. Microsc. Tech.

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It is shown that material segregated to grain boundaries can be lost during ion milling. This specimen preparation artifact has been studied in the case of bismuth in copper and has also been observed for phosphorus in stainless steel. The loss is associated with specimen heating during ion milling and can be alleviated by good clamping and cooling of the specimen during milling. Specimen heating permits grain boundary diffusion of the segregating element to the specimen surfaces with subsequent loss of segregant from the specimen by evaporation or sputtering during ion milling. Loss of bismuth during in situ heating to 200-300 degrees C is demonstrated. Therefore, care must be taken in specimen preparation for analytical electron microscopy measurement of such segregation. Similar effects may occur during ion milling of other materials, especially those where low thermal conductivity will result in high beam heating. In these cases, care must be taken to avoid loss of segregant during specimen preparation. Additional tests showed that no significant loss of segregant was observed during X-ray microanalysis, even at nominal room temperature and probe currents five-fold higher than that normally used for microanalysis.

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Section: Resultsmentioning

confidence: 99%

Loss of grain boundary segregant during ion milling

Kenik

1991

J. Elec. Microsc. Tech.

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“…[27]). Many have focused on Al 2 O 3 -based materials (e.g., [28][29][30][31][32][33][34]). Efforts have been made by Dillon et al [32][33][34] to relate and categorize the effects of grain boundary ''phases'' on grain growth and transport kinetics along grain boundaries.…”

Section: Intergranular Glassy Phase In Aluminamentioning

confidence: 99%

Silicide characterization at alumina–niobium interfaces

et al. 2011

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Alumina-niobium interfaces formed by liquidfilm-assisted joining with copper/niobium/copper interlayers exhibited microstructures that depend on the nature of the alumina components. Characterization of these interfaces in the transmission electron microscope provided insight on the relationship between interfacial microstructure and fracture performance. Interfaces between sapphire and niobium and those between high-purity (99.9%) polycrystalline alumina and niobium were free of secondary phases. However, niobium silicides were found at interfaces between lower-purity (99.5%) alumina and niobium, identified by electron diffraction analysis as the body-centered tetragonal a-Nb 5 Si 3 phase. Spatially resolved compositional analysis was conducted on silicide particles at and away from the interface.

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“…These artifacts can obscure the experimental results obtained when applying these characterization techniques by giving a misleading impression of the nature of the interface. The experimental evidence for the existence of such artifacts, and their effects on the observations and subsequent interpretations in applying the dark-field, diffuse-scattering technque, Fresnel fringe method and AEM using EDS have been discussed extensively in detail by Kouh Simpson et al [2]. The aim of this paper is to explore further the effects of ion-milling artifacts on the application of these techniques.…”

Section: Introductionmentioning

confidence: 94%

Grain-Boundary, Glassy-Phase Identification and Possible Artifacts

et al. 1985

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Specimen artifacts such as grain boundary grooving, surface damage of the specimen, and Si contamination are shown experimentally to arise from the ion milling used in the preparation of transmission electron microscopy specimens. These artifacts in polycrystalline, ceramic specimens can cause clean grain boundaries to appear to contain a glassy phase when the dark-field diffuse scattering technique, the Fresnel fringe technique, and analytical electron microscopy (energy dispersive spectroscopy) are used to identify glassy phases at a grain boundary. The ambiguity in interpereting each of these techniques due to the ion milling artifacts will be discussed from a theoretical view point and compared to experimental results obtained for alumina.

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The identification of thin amorphous films at grain-boundaries in Al2O3

Cited by 65 publications

References 15 publications

Loss of grain boundary segregant during ion milling

Loss of grain boundary segregant during ion milling

Silicide characterization at alumina–niobium interfaces

Grain-Boundary, Glassy-Phase Identification and Possible Artifacts

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