Equilibrium grain boundary segregation and clustering of impurities in colloidal polycrystalline monolayers
| Autor: | Dirk G. A. L. Aarts, Samuel Diana, Roel P. A. Dullens, François A. Lavergne |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Video microscopy 02 engineering and technology 010402 general chemistry 01 natural sciences Condensed Matter::Materials Science Impurity Condensed Matter::Superconductivity Monolayer Electrochemistry General Materials Science Spectroscopy food and beverages Surfaces and Interfaces Hard spheres 021001 nanoscience & nanotechnology Condensed Matter Physics Grain size 0104 chemical sciences Condensed Matter::Soft Condensed Matter Grain growth Crystallography Chemical physics Grain boundary Condensed Matter::Strongly Correlated Electrons Crystallite 0210 nano-technology |
| Zdroj: | Langmuir. 32(48) |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | We investigate the segregation of impurities to grain boundaries in colloidal polycrystalline monolayers using video-microscopy. A model colloidal alloy is prepared by embedding large spherical impurities in a polycrystalline monolayer of small host colloidal hard spheres, which stops grain growth at a finite grain size. The size ratio between the impurities and the host particles determines whether they behave as interstitial or substitutional impurities in the bulk crystal, akin to those in real alloys. We find that the partitioning of impurities between the grains and the grain boundaries is in very good agreement with the Langmuir-McLean adsorption model for equilibrium grain boundary segregation. This enables the direct measurement of the free energy of adsorption for the two types of impurities. Near saturation, we characterise the spatial distribution of the adsorbed impurities and find that it strongly depends on their interstitial or substitutional nature. This is because the relative importance of clustering and mixing due to non-additivity is determined by geometrical constraints imposed by the crystalline host lattice. |
| Databáze: | OpenAIRE |
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