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ChemistryInorganic Chemistry

What Xe Nanocrystals in Al Can Teach Us in Materials Science

Authors: C. W. Allen; R. C. Birtcher; U. Dahmen; K. Furuya; M. Song; NATIONAL INST FOR MATERIALS SCIENCE TSUKUBA (JAPAN)
Abstract:
Noble gases are generally very insoluble in solids. For example, Xe implanted into Al at 300 K forms a fine dispersion of crystalline precipitates and, at large enough fluence. fluid precipitates, both of which are stabilized, relative to the gas phase, by the Laplace pressure due to precipitate/matrix interface tensions. High resolution electron microscopy has been performed to determine the largest Xe nanocrystalline precipitate in local equilibrium with fluid Xe precipitates within the Al matrix. From the shape and size of the largest crystal and the Laplace pressure associated with its interface, we show that the interface tensions can he derived by setting the Laplace pressure equal to the pressure for solid/fluid Xe equilibrium derived from bulk Xe compression isotherms at the temperature of equilibration and observation. The Xe/Al interface tensions thus derived are in the range of accepted values of surface tensions for the Al matrix. Furthermore, it is suggested that this same technique may be employed to estimate unknown surface tensions of a solid matrix from the size and shape of maximal nanocrystals of a noble gas element, which have been equilibrated in that matrix at the temperature of observation.

Limitations: APPROVED FOR PUBLIC RELEASE
Pages: 6
Report Date: NOV 2001
Report Number: P242210
Keywords relating to this report:
*XENON
ALUMINUM
COALESCENCE
ELECTRON MICROSCOPY
HIGH RESOLUTION
JAPAN
MIGRATION
NANOTECHNOLOGY
PRECIPITATES
SURFACE TENSION
UNITED KINGDOM
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