| Autor: |
Ye Cai, Allan, Shawn M., Sandhage, Kenneth H., Zalar, Frank M. |
| Předmět: |
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| Zdroj: |
Journal of the American Ceramic Society; Jul2005, Vol. 88 Issue 7, p2005-2010, 6p |
| Abstrakt: |
A low-temperature (≤700°C) magnesiothermic reaction has been used for the first time to convert three-dimensional (3-D) silica-based diatom microshells into nanocrystalline magnesia-based replicas. Exposure of diatom microshells to Mg( g) at only 650°–700°C resulted in the initial (direct) formation of MgO and Si nanocrystals (≤5 nm), that is, no intermediate magnesium silicate compounds were detected. Further reaction of Si with Mg( g) led to the formation of Mg2Si, and then a Mg–Si liquid that sweated away to yield free-standing, nanocrystalline MgO-based replicas. Such direct low-temperature magnesiothermic conversion of diatom microshells enables the synthesis of large numbers of 3-D nanocrystal assemblies with well-controlled morphologies for catalytic/chemical, biological, optical, and other applications. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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