Rare gas bubbles in muscovite mica implanted with xenon and krypton
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F. Desage, C. Templier, and J. C. Desoyer Laboratoire de Metallurgie Physique, Universite de Poitiers, Poitiers Cedex 86022, France
R. C. Birtcher Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (Received 7 March 1994; accepted 29 August 1994)
Xenon and krypton have been implanted into muscovite mica at room temperature and at liquid nitrogen temperature. The behavior of the implanted Xe and Kr was followed by low-temperature transmission electron microscopy and energy dispersive x-ray analysis. An electron diffraction pattern of diffuse bands is observed at room temperature due to the presence of fluid rare gas and to noncrystalline mica. Visible cavities with diameters 10-300 nm formed in the Xe-implanted mica. Visible cavities in room-temperature Kr-implanted mica ranged from 5-50 nm in diameter. The gas pressures at room temperature in the cavities are estimated, assuming all of the implanted gas precipitated in cavities to be ~ 10 MPa for Xe and ~20 MPa for Kr. These pressures are considerably lower than found for rare gases implanted in metals and ceramics, but sufficient to liquefy the rare gases at room temperature. The Xe and Kr were observed by dark-field microscopy to form fee crystalline solids within the cavities at temperatures below their triple points, with lattice parameters of a(Xe) = 0.630 ± 0.0015 nm and fl(Kr) = 0.565 ± 0.005 nm. The solid Xe within bubbles was unstable under the electron beam of the transmission electron microscope at temperatures above 80 K, while the solid Kr within bubbles was unstable at temperatures as low as 35 K. The crystalline mica matrix undergoes a transformation from a crystalline structure to an amorphous structure as a result of implantation. I. INTRODUCTION Solidified rare gas bubbles formed after room temperature implantation have been found in metals1'2 and in ceramic materials3"6 due to the pressure exerted by the surrounding solid matrix. Room temperature implantations of rare gases into metals at fluences on the order of 1016 ions • cm" 2 lead to the formation of bubbles several nm in diameter under pressures of many GPa. Solid rare gas bubbles are crystalline, generally in epitaxy with the metal matrix, with fee lattices in fee or bee metals and hep lattices in hep metals. In the case of magnesia3-4-6 and yttria-stabilized zirconia (YSZ)5 ceramics, transmission electron microscopy studies revealed solid Xe crystalline inclusions in single crystal MgO at room temperature sometimes epitaxially related at pressures of approximately 0.5 GPa, and solid Kr at room temperature in MgO at internal pressures of 1.7 GPa. Single crystal YSZ have been implanted with Xe at room temperature, and both solid Xe and fluid Xe were observed at room temperature.
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at Midwest Research Technologies, Inc., Brookfield, Wisconsin 53005. J. Mater. Res., Vol. 9, No. 12, Dec 1994 http://journals.cambridge.org
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Implantation of mica perpendicular to the basal plane with noble gases is being considered for developme
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