Dimpling ductile materials

Why dimple TEM specimens?

Dimpling has become the preferred first step in transmission electron microscope (TEM) specimen preparation because (1) it greatly reduces the time necessary for final thinning to electron transparency (the time saving is especially great when the final polishing step is relatively slow as is the case in ion polishing); (2) the electron transparent area will always form at the center of the specimen disc and hence less x-ray shadowing will occur during energy dispersive x-ray spectroscopy (EDS) analysis and less specimen movement will occur during tilting; (3) the thick, supportive rim of material formed during dimpling greatly facilitates the handling of fragile, TEM specimens.