Comparisons of Techniques - Sample Preparation Topic for Transmission Electron Microscopy - page 214

3.2.3 Comparison of “Ultramicrotomy” and “Ion Milling” Techniques
Ion Milling Technique (“Techniques” Chapter 3, Section 5) and
Ultramicrotomy Technique (“Techniques” Chapter 4, Section 4)
Bulk material: cross section of a mica sample (mineral)
Comparison discussion : The mechanical polishing technique followed by the ion
milling technique results in the almost total destruction of the mica layers. It is
impossible to investigate the interfaces between the layers.
The ultramicrotomy technique yields excellent results: the layers are clearly vis-
ible, without alteration; therefore, the investigation of the interfaces between these
layers is possible, as is the chemical analysis of the compounds (Figs. 8.25 and
8.26) .
Fig. 8.25 Bright-field TEM
image of a cross section of a
mica sample thinned using
mechanical polishing,
followed by ion milling at
5 keV, two guns, angle of
incidence 16 ◦ , and sectorial
rotation (experimental
conditions). The sample is
thick. The layers of mica are
almost totally destroyed.
( D. Laub, EPFL - CIME,
Lausanne )
Fig. 8.26 Bright-field TEM
image of the same sample
prepared using the
ultramicrotomy technique.
Sample thickness: 70 nm.
( D. Laub, EPFL - CIME,
Lausanne )