Electron microscopy; proceedings of the Electron microscopy; proceedings of the Stockholm Conference, September, 1956 electronmicrosco00euro Year: 1957 Fig. 4. Controlled polishing at points on the characteristic voltage increments in the region AB were made small, and with adequate time intervals between them, the polishing curves were found to be reproducible. Expcrinie/itdl Proccdiiie. -In order to relate the struc- ture resulting from a polish to the polishing conditions, a polishing curve was hrst established for a given size of specimen and for fixed temperature and stirring speed. Foll
Electron microscopy; proceedings of the Electron microscopy; proceedings of the Stockholm Conference, September, 1956 electronmicrosco00euro Year: 1957 Fig. 4. Controlled polishing at points on the characteristic voltage increments in the region AB were made small, and with adequate time intervals between them, the polishing curves were found to be reproducible. Expcrinie/itdl Proccdiiie. -In order to relate the struc- ture resulting from a polish to the polishing conditions, a polishing curve was hrst established for a given size of specimen and for fixed temperature and stirring speed. Following the procedure described abo\e, a scries of similar aluminium specimens were polished under condi- tions defined by the points P^, P^, Pj ... on the portion CD of the curve (Fig. 4). After five minutes polishing at such a point, the specimen was removed from the bath with voltage still applied, washed in water and alcohol, and dried in warm air. It was found that thin unbacked films of formvar could be water stripped frotn the aluminium withcnit difficulty, provided that the process was completed within about half an hour of the preparation of the specimen. With greater delays than this, stripping became progres- sively more difficult, and, in some cases, a thick backing film had to be used. The replicas were subsequently shadow-cast. Several portions of each replica film were examined in the electron microscope, and a number of photographs taken at random on each; this ensured a representative selection of available structures. When structure appeared on a specimen, the di- mensions ( the separation of the furrows, the spacing of the dots, and the width of the elements of the whorls) were measured. It was found that these dimensions were substantially constant for a given aluminium specimen. Each specimen produced at the points F,, Pt, etc. on the polishing curve was found to have its own characteristic structure spacing. Fig. 3. Effects of temperature on polishing
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