Electropolishing is a well-known technique, mostly used to prepare (inter)metallic samples, because these materials are conducting, too soft for crushing, and easily damaged by conventional ion milling.
For instance, 3-mm discs in diameter were punched from alloy sheets of Al-1.5wt% Cu-4.0wt% Mg-0.5wt% Ag and then electropolished in a 1:2 nitric acid:methanol solution (by volume) with applied voltages between 12 and 14V at a temperature of 253K .
Table 4488. Examples of electropolishing for TEM sample preparation.
|Materials in TEM sample
|Al-1.5wt% Cu-4.0wt% Mg-0.5wt% Ag
||1:2 nitric acid:methanol solution (by volume)
||Between 12 and 14V
||- 20 °C
||8% perchloric acid in methanol
||8% perchloric acid + 92% methanol
However, electropolished specimen can be contaminated by residues from either the electrolyte used for thinning or the solvents used for cleaning.
 Harsh Deep Chopra, The structure of primary strengthening precipitates in an Al-1.5wt% Cu-4.0wt% Mg-0.5wt% Ag alloy, Philosophical Magazine Letters, 73:6, 351-358 (1996).
 Wim Sillekens, Sean Agnew, Neale Neelameggham, Suveen Mathaudhu, Magnesium Technology 2011.
 Proceedings of the 2014 Energy Materials Conference, The Minerals, Metals & Materials Society (TMS), Xi'an, Shaanxi Province.