Apparatus for the rapid electrolytic preparation of thin metal foils for transmission electron microscopy

By thinning and perforating electrolytically 3 mm discs (the usual diameter of electron microscope holders) 100 μ to 200 μ thick, we prepare foils of iron and nickel of acceptable quality, i.e. containing enough thin areas to permit transmission electron microscope observations. Previous theories of electrolytic polishing are presented. We then study an electrolytic jet thinning technique in which two jets of electrolyte impinge onto the specimen, the entire system being immersed in a bath of the same electrolyte (electrolyte jet - in - electrolyte). A brief description is given of the construction and use of the apparatus. The basic technique can be modified for specialized applications, namely thicker and other materials (alloys, stainless steels, uranium carbide, copper,...) and low temperature electrolytic thinning. (authors)