The Anodic Sectioning of Beryllium

The anodic sectioning of a metal permits successive atomically thin layers (2.6-17 nm in the case of Be) to be removed from the surface of macroscopic specimens. The procedure with Be is based on forming an amorphous anodic film in an ethylene-glycol based electrolyte containing sulfate and phosphate ions, followed by dissolving the film in 10% KOH. The inorganic ions replace part of the O2− in the anodic film, the empirical result of this being that P-containing ions reduce the dissolution rate during anodizing whereas S-containing ions increase the dissolution rate of already-grown films in KOH. Thickness calibrations, based on a combination of measuring weight changes and analyzing depth-distribution curves for implanted radioactive ions, may be expressed as follows The logic used for arriving at the results is developed So that it can in principle be used as a guide for establishing anodic-sectioning procedures with still unstudied systems. Examples of depth distributions of 5, 15, and 80 keV Kr+ in both Be and the anodic film on Be are given. © 1980, The Electrochemical Society, Inc. All rights reserved.