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Ion Micromilling Applied to the Ultramicroscopic Study of Soils
Author(s) -
Bresson L.M.
Publication year - 1981
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1981.03615995004500030027x
Subject(s) - materials science , transmission electron microscopy , weathering , microstructure , ion , mineralogy , composite material , sample preparation , geology , chemistry , nanotechnology , geochemistry , organic chemistry , chromatography
The electron transmission microscopic (TEM) study of undisturbed soil materials requires the preparation of thin sections of about 1,000Ä thick. This seems to be possible only by ion micromilling. This thinning technique necessitates particular precautions due to the fragility of permeated soil materials. The resins generally used for the making of thin sections are suitable as long as their polymerization is very good. Handling of the sample must be done under a stereomicrosocope with great care. It may prove useful before bombardment to glue the sample (3 mm in diam, 30 µm in thickness) between two electron microscope grids with a single central hole. The required thickness is reached when small holes appear in the sample. The thickness of the ultrathin sections can be irregular because the thinning rate of the sample varies considerably with its chemical composition, the type of its crystal lattice, and the state of its surface. Therefore, the only areas visible with a TEM appear as halos around holes. Artifacts induced by ion bombardment seem to be negligible compared with those that appear during observation by TEM. The ultrathin sections thus obtained allow the morphology of soil constituents and their ultramicroorganization to be studied at very high magnifications; hence, they are extremely useful for studies of mineral weathering, microstructures, and microfabrics.